ESE's works engine tuner

[TZ350]

254282

maybe its true, that pigs can fly ...... :D

[Buckets4Me]

Im sure this is way over 400hp/litre

Not sure of the STAs though

254278
254279
254280

254277

I might try some nytomethane in the bike and see how it goes as well

[speedpro]

Baby bees are cool. Good little hovercraft engines with the spring recoil starter.

[TZ350]

EngMod2T

Grumph sent me some ideas about fitting a resonator after the carb, with his permision I have posted them.

"If I was you I'd try a proper heimoltz resonator....About 2 X cylinder volume and with a 24mm inlet.

with the big open end you're not getting the best from it.

the original use for them was F3 car motors - 1300cc if I have it right - but they were restricted to a 30mm ID inlet - the FIA wanted a 30mm carb obviously. What the builders did was short inlets into a log manifold - the resonator - with a 30mm inlet trumpet stuck on one end. With port injection they got better power than individual runner injection.

NASCAR V8's have used this setup with the restrictor carbs - one resonator per bank. Grumph"

254305 bend made from a SU carb air cleaner manifold.

254310 flow guide inside the SU bend.

I was happy because it might mean I can recycle this piece by adding some volume to it and get the carb moved up out of the way.

254307 1ex port.

After a bit of work modeling the resonator I got to the red line then by adding a 160mm piece in front of the carb I got to the blue line. So it appears that if you can get the two different resonant systems working together they pass more air.

254308 3ex port.

And with the tripple port using both systems together they did away with the need to vary the length of the first resonant chamber like I had to in my original model.

254309 the before and after carb elements in the inlet system.

If you have to have a manifold and some sort of inlet duct between the engine and carb why not look into using them as tuning elements.

Now I don't for a moment think that I have got it sussed but it is food for thought and a bit of a plan to work on over the next few weeks.

[dinamik2t]

Great ideas!
I love your hunger for simulating alternative mods in EngMod, TZ!:first: I will experiment on my inlet too when I return home.
Have you been monitoring the inlet pressure waves during the testing??

[TZ350]

Travel adventures ... have you enjoyed your time away.


Great ideas! ... Have you been monitoring the inlet pressure waves during the testing??

No ... simulations take about 5-10 min, I do small chores around the house. But that is a good idea, I could learn a lot from it.

[Kickaha]

Anyone like playing around in boats? http://www.boatracingfacts.com/forums/showthread.php?t=5509
254315254316254314 254317254318

[TZ350]

That is pretty amazing ....

[dmcca]

Really enjoying your engmod2t work TZ...

Engmod2T question...
So far I've only modelled from the carb into the engine on my bike and haven't tried to model the odd shaped rubber intake boot, air filter or air box (CR250, all typical dirt bike stuff) that are positioned before the carb...

After reading TZ's posts plus other things on the net I want to try modelling them to see the exact effects... Any suggestions on the best way to model these given the strange shapes? Might go into the shed and start measuring to see what I come up with...

[TZ350]

Modelling the intake side, I think this is an important area, and I don't know much about it or how to use Engmod2T properly to do it, I am just learning myself.

Asking Wobbly or Frits or even the Neels himself would be good. I think there is a lot to be gained here, (or lost).

Grumphs idea of a resonator behined the carb and mine of having one in front working in concert with it to shift bulk air through a restrictive 24mm carb could be a fruitfull area of development.

[TZ350]

254336CRECY ..... sleeve valve 2-Stroke, one of the most powerfull internal combustion engines ever made.

A quick Google (and display "Images") brings up some interesting info.

[bucketracer]

EngMod2T

And with the tripple port using both systems together they did away with the need to vary the length of the first resonant chamber like I had to in my original model.

254309 the before and after carb elements in the inlet system.

If you have to have a manifold and some sort of inlet duct between the engine and carb why not look into using them as tuning elements.

I was looking at your model, I assume the thin bit in the middle is the carb. 75mm for the front end seemed rather large until I worked out that 12,000 rpm is 200 Hz base speaker territory, so low frequency = big volumes.

Ever thought about using a base speaker as an exciter, it could be powered from a winding on the stator that way it would be timed to the crank.

[Frits Overmars]

254336CRECY ..... sleeve valve 2-Stroke, one of the most powerfull internal combustion engines ever made.Really? How many ponies are in there? 3000? This will teach you to be more careful with your remarks, TeeZee :first:

[wobbly]

It has always amazed me that people spend a fortune buying - building,a high performance race engines like the Konig above.
Then they use a hacksaw cut exhaust U bend for the header, and birdshit Mig weld it together - then more amazing, put the pieces of shit on the web for us to oggle at.
Makes you wonder at the workmanship and thus the integrity of the rest of the project.
Biased yes, of course - but an autistic blind 5 year old could weld better than some of the things I have seen proudly demonstrated by some 2 stroke ingineers on the interwebby thing.

[husaberg]

Really? How many ponies are in there? 3000? This will teach you to be more careful with your remarks, TeeZee :first:

just saw the pic of the marine engine frits posted...here's a response from Grumph attached below.

Then Wobs bit.Which was clearly obliviously aimed straight at my woeful welding and horrible fabrication.


Biased yes, of course - but an autistic blind 5 year old could weld better than some

I object to that.
Some of those blind autistic welders are Damn good. My own welding is more artistic than Autistic
The birdshit is purely for additional texture.I want my work to be a tactile experience.:lol:

[TZ350]

Really? How many ponies are in there? 3000?

254375

This will teach you to be more careful with your remarks, TeeZee :first:


Arrrr words and the games we play with them ... :laugh: ... Glad I said "one of the most powerfull", actually its a bit of a tiddler compaired to yours. I wanted to say aero engine but that would have given the game away. Maybe I should have just said "big grunty engine compaired to a Morris Minor".

254373254370 development was heading towards 5,000 bhp


There are various numbers bandied about, but this from Wiki.

The progress of jet engine development overtook that of the Crecy and replaced the need for this engine. As a result the project was cancelled in December 1945 at which point only six complete examples had been built, however an additional eight V-twins were built during the project. Crecy s/n 10 achieved 1,798 horsepower (1,341 kW) on 21 December 1944 which after adjustment for the inclusion of an exhaust turbine would have equated to 2,500 horsepower (1,900 kW).[11] (http://en.wikipedia.org/wiki/Rolls-Royce_Crecy#cite_note-10) Subsequent single-cylinder tests[12] (http://en.wikipedia.org/wiki/Rolls-Royce_Crecy#cite_note-11) achieved the equivalent of 5,000 brake horsepower (3,700 kW) for the complete engine. By June 1945 a total of 1,060 hours had been run on the V12 engines with a further 8,600 hours of testing on the V-twins.[13] (http://en.wikipedia.org/wiki/Rolls-Royce_Crecy#cite_note-12) The fate of the six Crecy engines remains unknown.

[husaberg]

Really? How many ponies are in there? 3000? This will teach you to be more careful with your remarks, TeeZee :first:

Some more light able to be shed on this tasty little Italian Aprilia esp the semi active suspension. 1992

Another question was to do with the Dellorto carbs.
Were other carbs tried or were the Dellottos better suited to the Disk valve engine or were there other considerations.
Such as their Italianess or sponsorship (I see there is a sponsor sticker on the fairing) or just as case of sticking with what the team was familiar with.
One last thing was that you mentioned in the pit lane thread about the electric power-jet when did Aprilia implement this?. You also mentioned about a car solenoid or stepper motor. A Fiat Uno one why did you go to a Keihin part.

[husaberg]

10 characters plus the carb pics of the Dellortos of the Pitlane thread.

[2T Institute]

The other question was to do with the Dellorto carbs.
Were other carbs tried or were the Dellottos better suited to the Disk valve engine or were there other considerations.
Such as their Italianess or sponsorship (I see there is a sponsor sticker on the fairing) or just as case of sticking with what the team was familiar with.

Dellorto's have been gracing Rotax engines first , with the bore size growing to 39.5mm on the VHSB body, then after Aprilia took over the engine production the VHSD appeared with a 41mm bore then the first generation S-DAS (stepper motor driven power jet) then the pulsed power jet and the latest VHSG 42mm with the APX electronics .
Unsure if other carbs were tried but never seen an Aprilia RSA/RSW without one. I'm not sure but I think it was more down to Dellorto working closely with Aprilia and a pinch of nationalistic pride. No doubt they work very well and if it aint broke.....................

An area of differentiation seems to be in bellmouth designs which each team seems to have their own idea on what the form should be.

[TZ350]

Ok this is where I am at now. The pumper didn't like it, I don't think it could shift enough fuel. I fitted the 24/28 that had run reasionably well before (28.9rwhp) and found it needed to go from a 140 main to a 150 and spent some time adjusting the ignition curve. It didn't lose power, which it usualy does when I try to improve things and it didn't shit itself on the dyno, so not bad all in all.

254462 1ex + RS pipe and Wobbly polish to my EngMod2T simulation model.

Todays dyno run hand drawn in blue and overlaid on the EngMod2T simulation graph.

Down 7hp on target and cuts off abruptly at 12,000 ish. The interesting thing is the torqe starts to realy pickup towards 11 ish and looks like it should start to fly but no matter what I did I could not get it past the wall at 12K.

At the moment something is choking it, I know I will get it right, maybe its time for that matching Wobbly pipe.

[diesel pig]

Down 7hp on target and cuts off abruptly at 12,000 ish. The interesting thing is the torqe starts to realy pickup towards11 ish and looks like it should start to fly but no matter what I did I could not get it past the wall at 12K.


Is that not what solenoid power jets are for? The Overrev?

[Grumph]

Are you running the resonator between carb and motor ?
It looks a bit like you're running into a bad resonance period - try shortening/reducing volume of the resonator.

[wobbly]

Now Neels has added a facility to produce engine power from dyno power numbers, here is what I have actually measured.
This is dyno curve on a Dynojet 168 with plenty of eddy current load to simulate real road use, with rear wheel Hp.
Then there is the sim of the 485 Cheetah cylindered RZ.
And a check of the difference.
12 to 18% between rear wheel and crank.

PS to TeeZee,before we do a hard pipe - what is the 40mm section at the beginning of the RS125 pipe in your sim - I used this in the sim with my design, is it necessary or can we make a "normal" flange around 25mm long.

[husaberg]

Arrrr words and the games we play with them ... :laugh: ... Glad I said "one of the most powerfull", actually its a bit of a tiddler compaired to yours. I wanted to say aero engine but that would have given the game away. Maybe I should have just said "big grunty engine compaired to a Morris Minor".

development was heading towards 5,000 bhp


There are various numbers bandied about, but this from Wiki.



Bar and Stroud was a popular sleeve valve engine to be fitted to the early motor cycles. such as Grindley pearless a make later made famous by one C.W.G (Bill) Lacey. (He used J.A.P conventional engines Though)
These engines were popular partly because of there almost silent operation.
unfortuantly it was never developed to the same extent as the multi cylinders used on the aeroplanes and and for cars.
This was also it the wiki article TZee quoted which i found interesting.



http://en.wikipedia.org/wiki/Sleeve_valve (http://en.wikipedia.org/wiki/Sleeve_valve)

Advantages

The main advantages of the sleeve-valve engine are:


Increased volumetric efficiency (http://www.kiwibiker.co.nz/wiki/Volumetric_efficiency) due to very large port openings. Sir Harry Ricardo (http://www.kiwibiker.co.nz/wiki/Harry_Ricardo) also demonstrated better mechanical efficiency. An additional advantage of the system is that the size of the ports can be readily controlled. This is important when an engine operates over a wide RPM range, since the speed at which air can enter and exit the cylinder is defined by the size of the duct leading to the cylinder, and varies according to the cube of the RPM. In other words, at higher RPM the engine typically requires larger ports that remain open for a greater proportion of the cycle, which is fairly easy to achieve with sleeve valves, but difficult in a poppet valve system.



Good exhaust scavenging and controllable swirl of the inlet air/fuel mixture in single-sleeve designs. When the intake ports open, the fuel air mixture can be made to enter tangentially to the cylinder. This helps scavenging when exhaust/inlet timing overlap is used and a wide speed range required, whereas poor poppet valve exhaust scavenging can dilute the fresh air/fuel mixture intake to a greater degree, being more speed dependent (relying principally on exhaust/inlet system resonant tuning to separate the two streams). Greater freedom of combustion chamber design (few constraints other than the spark plug positioning) means that fuel/air mixture swirl at TDC can also be more controlled allowing improved ignition and flame travel which as demonstrated by Ricardo, at least one extra unit of compression ratio before detonation c.f. the poppet valve engine.



The combustion chamber (http://www.kiwibiker.co.nz/wiki/Combustion_chamber) formed with the sleeve at the top of its stroke is ideal for complete, detonation-free combustion of the charge, as it does not have to contend with compromised chamber shape and hot exhaust (poppet) valve(s).



No springs are involved in the sleeve valve system, therefore the power needed to operate the valve remains largely constant with the engine's RPM (http://www.kiwibiker.co.nz/wiki/Revolutions_per_minute), meaning that the system can be used at very high speeds with no penalty for doing so. A problem with high-speed engines which use poppet valves is that as engine speed increases, the speed at which the valve moves also has to increase. This in turn increases the loads involved due to the inertia of the valve, which has to be opened quickly, brought to a stop, then reversed in direction and closed and brought to a stop again. Large valves that allow good air-flow have considerable mass and require a strong spring to overcome the opening inertia. At some point, the valve spring reaches its resonance frequency (http://www.kiwibiker.co.nz/wiki/Resonance), causing a compression wave to oscillate within the spring, which in turn causes it to become effectively weaker and unable to properly close the valve. This valve float (http://www.kiwibiker.co.nz/wiki/Valve_float) can result in the valve not closing quickly, and it may strike the top of the rising piston. In addition, camshaft, pushrods, and valve rockers can be eliminated in a sleeve valve design, as the sleeve valves are generally driven by a single gear powered from the crankshaft. In an aircraft engine this provided reductions in weight and complexity.



Longevity, as demonstrated in early automotive applications of the Knight engine. Prior to the advent of leaded gasolines, poppet-valve engines typically required grinding of the valves and valve seats after 20,000 to 30,000 miles (32,000 to 48,000 km) of service. Sleeve valves did not suffer from the wear and recession caused by the repetitive impact of the poppet valve against its seat. Sleeve valves were also subjected to less intense heat buildup than poppet valves, owing to their greater area of contact with other metal surfaces. In the Knight engine, carbon build-up actually helped to improve the sealing of the sleeves, the engines being said to "improve with use", in contrast to poppet valve engines, which lose compression and power as valves and valve stems/guides wear. Due to the continued motion of the sleeve (Burt-McCollum type), the high wear points linked to poor lubrication in the TDC/BDC of piston course are suppressed, therefore rings and cylinders lasted much longer.



Cylinder head is not required to house valves, allowing the spark plug to be placed in the best possible location for efficient ignition of the combustion mixture. For very big engines, where flame propagation speed limits both size and speed, the swirl induced by ports as described by Ricardo can be an additional advantage.



Continental in the USA conducted extensive research in Single-Sleeve-Valve engines, pointing that they were eventually of lower production cost, and easier to produce, however, their aircraft engines soon equaled the SSV engines performance by introducing improvements such as Sodium cooled poppet valves, and it seems also that the costs of this research, along with the October 1929 crisis, lead to the Continental SSV engines not entering mass production. ( Continental ! Its Motors and its People. William Wagner, 1983, p. 33 ). The same book reports that General Motors had made tests with SSV engines, rejecting this kind of arrangement.


Most of these advantages were evaluated and established during the 1920s by Sir Harry Ricardo, possibly the sleeve-valve engine's greatest advocate. He conceded that some of these advantages were significantly eroded as fuels improved up to and during World War II and as sodium-cooled exhaust valves were introduced in high output aircraft engines.


Mike Hewland (http://en.wikipedia.org/w/index.php?title=Mike_Hewland&action=edit&redlink=1) with his assistant John Logan, and Keith Duckworth (http://en.wikipedia.org/wiki/Keith_Duckworth) experimented with a single-cylinder sleeve-valve test engine when looking at Cosworth DFV (http://en.wikipedia.org/wiki/Cosworth_DFV) replacements. Hewland claimed to have obtained 72 hp (54 kW) from a 500 cc single-cylinder engine, with a specific fuel consumption (http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption) of 170 gr/HP/hr -.45 to .39 lb/hp/hr-, the engine being able to work on creosote (http://en.wikipedia.org/wiki/Creosote), with no specific lubrication supply for the sleeve, just the sleeve driving mechanism requires an specially devoted lubrication. Hewland reported also that the highest temperature measured in the cylinder head didn't exceed 150 °C, sleeve temperatures were around 140 °C, T was 270 °C in the center of cylinder and 240 °C in the edge.

A recent SAE paper deals with a high-speed, small-displacement sleeve-valve engine, calculated, but not experimentally shown, to have a higher SFC than the poppet-valve alternative, a non-surprising result, considering the difficulty in obtaining the high intake and exhaust overlap that very fast-running engines require, additional work compares two different side-opening intake strategies for sleeve-valve engines.

[TZ350]

254506

After a bit of fiddling it was starting to carberate realy well, it could even pull away from idle (idles 3,500rpm). Then it began making a hell of a racket, like a hole in the exhaust, I couldn't see anything so possibly a blown head gasket. Anyway its time to take the barrel of and check the piston, I will investigate tommorow.

[TZ350]

EngMod2T


Now Neels has added a facility to produce engine power from dyno power numbers, here is what I have actually measured.

254520

....sim of the 485 Cheetah cylindered RZ, the difference.12 to 18% between rear wheel and crank.


Neels sent me an update today that allowed the creation of a measured power file with a correction factor for transmission power loss.

254521

Blue line is the simulated engine and the Red line is what I measured on the dyno. I used 16% loss as the correction factor which is sort of mid way between the 12-18% on Wobblys chart.

Now I can truly compare apples with apples and overlay my dyno graph as crank HP on the simulators graph to see where I need to look to iron out the power bugs.

This EngMod2T package is great, here I have an expert system telling me what it thinks is possible with what parts (porting, cyl head, chamber, carb) I have compared to what I am getting.

There are obviously problems with my interpretation of the plan, now to find and correct my build errors.

[koba]

EngMod2T



Neels sent me an update today that allowed the creation of a measured power file with a correction factor for transmission power loss.

254521

Blue line is the simulated engine and the red line is what I measured on the dyno. I used 16% loss as the correction factor which is sort of mid way between the 12-18% on Wobblys chart.

Now I can truly compare apples with apples and overlay my dyno graph as crank HP on the simulators graph to see where I need to look to iron out the power bugs.

This EngMod2T package is great, here I have an expert system telling me what it thinks is possible with what I have compared to what I am getting.

There are obviously problems with my interpretation of the plan, now to find and correct the build errors.

Are you saying you dynoed a legal bucket at 33hp?!?!

[Henk]

Are you saying you dynoed a legal bucket at 33hp?!?!

Not yet, these are simulation runs as far as I'm aware.

[koba]

Blue line is the simulated engine and the red line is what I measured on the dyno. I used 16% loss as the correction factor which is sort of mid way between the 12-18% on Wobblys chart.

Now I can truly compare apples with apples and overlay my dyno graph as crank HP on the simulators graph to see where I need to look to iron out the power bugs.



Not yet, these are simulation runs as far as I'm aware.

So is that 33hp on the dyno or is 33hp the sim result minus the percentage loss you expect?

[TZ350]

Are you saying you dynoed a legal bucket at 33hp?!?!

Yes 33 crankshaft hp. (if transmission losses are 16%)

The dyno measures rear wheel HP, the simulation simulates crankshaft HP there is some losses between the crank and what rolling roads measure at the rear wheel.

EngMod2T has a function where you hand enter the rear wheel dyno results and a correction factor and it prints out crank HP.

If the loss is truly 16% (at the moment 16 is a guesstimate) then my bike makes (Red line) about 33hp at the crank at 11,750 rpm, calculated (with guesstimate correction) from the 28.7 rear wheel hp as measured on the dyno. If the true losses are less than 16% then my engine is making less than 33 crank hp. I am just not sure what the real losses are yet.

Husaburg suggested to me that the dyno can be used to measure roll down resistance, I am not sure if thats the same as transmission loss but I will look into it, if it is then I can get a more accurate figure for the correction factor.

[koba]

Right, Gotcha now.

[husaberg]

Yes 33 crankshaft hp. (if transmission losses are 16%)

The dyno measures rear wheel HP, the simulation simulates crankshaft HP there is some losses between the crank and what rolling roads measure at the rear wheel.

EngMod2T has a function where you hand enter the rear wheel dyno results and a correction factor and it prints out crank HP.

If the loss is truly 16% (at the moment 16 is a guesstimate) then my bike makes (Red line) about 33hp at the crank at 11,750 rpm, calculated (with guesstimate correction) from the 28.7 rear wheel hp as measured on the dyno. If the true losses are less than 16% then my engine is making less than 33 crank hp. I am just not sure what the real losses are yet.

Husaburg suggested to me that the dyno can be used to measure roll down resistance, I am not sure if thats the same as transmission loss but I will look into it, if it is then I can get a more accurate figure for the correction factor.

It turns out the Dynojet most likely can't .
But my line of thinking is it's is wrong to use a percentage figure for transmission loss based on the total HP.
Why say for instance TZeds bike makes 30hp at the rear wheel right if the transmission is estimated at say 10% that is 3 hp right.
Say the exact same model of bike without TZed tuning makes 15 hp so the loss would be 1.5hp but they have the exact same transmission?
Or if TZed finds a extra 10 hp to get to 40hp all of a sudden the same transmission absorbs 4 hp.
I am of course assuming the revs are all the same.

I think one that does calculate transmission losses is a FLA type dyno which has a eddy current dyno built into the flywheel to measure trans losses (According to John Robinson) although maybe the later dynojets do have one now? As the FLA is unlikely to be one around i guess or do a coast down test from a predetermined speed on flat ground no wind from a speed low enough to cancel out the air Resistance to a extent.If we know the weight of the bike and rider and the speeds and time we should be able to calculate the drag.
Of course you could get a alternator and see what it does take to run the bike down in neutral.

Added the Bud Aksland stuff as i tripped over it today.
The other one was in something i posted a week or so ago.

[wobbly]

I have visited Buds facility several times and its an amazing combination of super Hi Tech and super basic.
The main area is a big shipping container, with an office built outside one end, that sits in the yard of
a transport company.
The dyno is a Heenan eddy current using Depac software, inside the container.
Inside the "office" is a CNC anenometric flow visualiser, and a phone.
In the middle is a work area for grinding and pipe building, done by a Kiwi guy I cant remember his name - he was the crew chief
on Kocincis World Champ effort on the Yamaha, he took an instant dislike to me when I suggested that Little John had won the title despite the bike - as it
was easily the slowest in the field that year.

Re the dyno vs crank conversion.Many people have done this check on many setups, and the general consensus is that when using an inertia dyno on the sprocket
the difference is around 5 - 8% , and when using the rear wheel the difference is 12 to 16%.
These are the losses in the transmission/chain/tyre etc and seem to very similar % wise for a 125GP or a 1000 Superbike.
The BSL made 55 Hp per cylinder on the single with a crank driven dyno, at the same stage the triple in the bike read 142 at the rear wheel on a Dynojet - you do the math.
Really who gives a shit about the actual raw numbers generated, as long as the power curve shape and peak rpm point coincide between reality and the sim,then both the dyno and the sim can highlight if a change is better or worse.
The sims nowdays are a very good prediction tool, and way quicker/cheaper than the time spent cutting/shutting and dynoing for hours - unless of course you are being paid to do it..

[jasonu]

In the middle is a work area for grinding and pipe building, done by a Kiwi guy I cant remember his name - he was the crew chief
..

Possibly Norris Farrow???

[husaberg]

In the middle is a work area for grinding and pipe building, done by a Kiwi guy I cant remember his name - he was the crew chief
on Kocincis World Champ effort on the Yamaha, he took an instant dislike to me when I suggested that Little John had won the title despite the bike - as it was easily the slowest in the field that year.



Imagine being Kocinski Crew chief for a minute, sure the guy was mega talented, But WTF.
If you believe even 10% of was was written about him.
I read an interview done with him the other day crickey.
But the little bugger was magic to watch when on song.
Having said that it looks like he may have came out better than Gobert.
Plus why does that name seem so familiar Norris Farrow.
Did he campaign a modded RD350 in Europe in a TZ frame late 70's?

Also added a Apitec and GKN blub missing a page or two bugger maybe someone has the last ones.
What interested me was the squeeze form liners i am not even sure if they still make then as they aren't listed o the either web site.
The site is interesting in which the repairs are carried out i was wondering why i couldn't strip then tig up the whole cylinder and then machine it and re-coat it rather than a sleeve anyway.

Re coating i am not suggesting to send stuff oversea when we have a place in NZ.
Plus yes it would be easier to sleeve a cylinder.

http://www.poetonaptec.co.uk/default.htm
http://www.gkn.com/Pages/default.aspx

[TZ350]

I have become very interested in how to use a rolling road dyno properly and the inherant errors in inertia dynos used for measuring RWHP.

Comments I have found on the net.

Chassis dynos are great tuning aids but they only give a approximation of power output as some of the important variables are not accurately controlled. When all things are kept the same between runs and you get a tangible gain, it is a gain at least. How much, is open for discussion.

As most people know, there are power losses through the drivetrain so wheel hp is always lower than flywheel hp. Tire pressure and wheel alignment can have very significant effects on losses at the rollers. Tire pressures should be set the same between each test. Tire rolling resistance varies inversely with speed, another factor not taken into account or different inertial weight of different tyres and wheels, after all its an inertia dyno and changing the overall inertial weight that has to be spun up changes the HP reading.

An engine in a bike with lighter wheels will show more HP than the same engine in a bike with heavy wheels, One of our GP 125 engines in an RS125 chassis with its light wheels is easier to spin up then an FZR with its heavy wheels and so the engine in the RS chassis will show more HP on a rolling road dyno like our DynoJet.

Food for thought on dyno errors and dyno technique.

http://www.sdsefi.com/techdyno.htm
http://www.stahlheaders.com/Lit_Dyno%20info.htm
http://www.modified.com/editors/technobabble/9907scc_technobabble/index.html
http://www.pumaracing.co.uk/POWER3.htm
http://www.pumaracing.co.uk/coastdwn.htm

And other mistakes you can make on a rolling road dyno ...

<iframe width="420" height="315" src="http://www.youtube.com/embed/Kes-L2KuJos" frameborder="0" allowfullscreen></iframe>

<iframe width="420" height="315" src="http://www.youtube.com/embed/1rtXsGC-q3Q" frameborder="0" allowfullscreen></iframe>

[Frits Overmars]

....it would be easier to sleeve a cylinder.It would be even easier to bin it. And more sensible too, if you allow me to exaggerate just a bit.
Pressing in a sleeve is a no-no to begin with. Shrinking it in is better, but not good enough. Because no matter how tight you make that interference fit, during use oil will creep between cylinder and liner, starting at the exhaust port.
If you remove an old liner, you can see the charred remains of that oil all around the exhaust zone. So do not worry about the limited thermal conductivity of an iron liner; charred oil conducts heat infinitely worse.
Been there, done that. If there's anything that makes me experienced in the two-stroke field, it's the fact that I have personally committed every imaginable error. Racing an air-cooled 500 cc two-stroke single with a liner made me the fastest man in Holland - in drawing a clutch. Not even Lucky Luke could draw quicker :shifty:.

[Frits Overmars]

Chassis dynos are great tuning aids but they only give a approximation of power output as some of the important variables are not accurately controlled... Tire pressure and wheel alignment can have very significant effects on losses at the rollers. Tire pressures should be set the same between each test.Nothing is stopping you...

Another factor not taken into account or different inertial weight of different tyres and wheels, after all its an inertia dyno and changing the overall inertial weight that has to be spun up changes the HP reading. An engine in a bike with lighter wheels will show more HP than the same engine in a bike with heavy wheels.Which makes an inertial dyno the perfect instrument for the development of competition engines. Because that is reality: a bike with lighter wheels will accelerate a bit faster.
Use a gearing on the dyno that gives you an acceleration time, equal to the time between gear shifts at the track. Then you will measure the engine the way it has to perform in real life. And the biggest advantage will be that the exhaust pipe will then heat up and cool down on the dyno just like it does on the track.

Earlier a lot has been said about measuring the losses between dyno and crankshaft. Forget about that; it's bullshit.
Losses caused by friction between gears are load-dependent. You cannot establish those by way of a coast-down measurement, because once the engine power is gone, the load is gone (or at least decimated).
If you want to be taken seriously, then only talk about horsepower you actually measured. If you want to talk crankshaft power, measure at the crankshaft.

[wobbly]

The old chestnut about heavy wheels and even worse the shitbox Harleys that have heavy flywheels "causing them "to make less power than a wee kart engine
on the rollers is a huge crock of shit.
The reality of the situation seems to escape some very clever people, alot of whom post on the net and sell dyno's as well - funny that.
At the end of the day the reason we put the kart - engine, bike, jetski, on the dyno is to achieve a "better " state of tune.
Once that is done, then taking the FZR and fitting light wheels will make it produce more "power " and it will be faster on the track because of this.
Changing from cast iron wheels, to carbon composite wheels is a "tuning" aid , just as much as a Wobbly pipe might be.
The rolling road will show this - the engine dyno wont.
Again as I keep saying - who gives a shit - if it makes more power on any dyno, no matter what the number is, it will be faster.

[husaberg]

It would be even easier to bin it. And more sensible too, if you allow me to exaggerate just a bit.
Pressing in a sleeve is a no-no to begin with. Shrinking it in is better, but not good enough. Because no matter how tight you make that interference fit, during use oil will creep between cylinder and liner, starting at the exhaust port.
If you remove an old liner, you can see the charred remains of that oil all around the exhaust zone. So do not worry about the limited thermal conductivity of an iron liner; charred oil conducts heat infinitely worse.
Been there, done that. If there's anything that makes me experienced in the two-stroke field, it's the fact that I have personally committed every imaginable error. Racing an air-cooled 500 cc two-stroke single with a liner made me the fastest man in Holland - in drawing a clutch. Not even Lucky Luke could draw quicker :shifty:.

Noted Frits. I know you are on the money there.
But the problem i face is Honda were not aware that i wanted a 50mm bore and not a 54mm bore they also cocked up the stroke a bit as well, Bloody Honda. I still do love them though. Its just they may not get lucky tonight that's all.

PS You never replied to the Aprilia Dellorto stuff. I checked it only mentioned "Macbeth" twice.Whoops forgot to blackout
Also when are the FOS cylinder going to be available in a 50mm bore?

The other bit Frits what i think TZ is trying to do is get the sim to match the Dyno.
To do that he needs to acturatly establish the crank HP. He want to get it as close as pos.

[TZ350]

If you want to be taken seriously, then only talk about horsepower you actually measured. If you want to talk crankshaft power, measure at the crankshaft. Or shut it.

Bit harsh but deserved I suppose because after all I did spell your name wrong.... :laugh:

Just for those experts that might find themselves frustrated with those of us learning this craft ..... this is our hobby and to be enjoyed.... If I want grumpyness I can go to work and be paid to enjoy it.

[Frits Overmars]

PS You never replied to the Aprilia Dellorto stuff.They say the second thing to go is the memory, and I can't remember what the first thing was. Honestly Husaberg, I cannot recall that question. I either missed it or it was something I could not answer for one reason or another.
when are the FOS cylinders going to be available in a 50mm bore?That may be quite a while. But the idea is so simple; build one yourself. In fact that would be much easier than building a conventional cylinder.
In a conventional jug you need five differently-shaped transfer ducts; in my system you need only one shape, six times. And you need one bridged exhaust duct, twice. Don't you love symmetry?

[Frits Overmars]

Bit harsh but deserved I suppose because after all I did spell your name wrong.... :laugh:.Don't worry about that spelling. I'm not one to hold a grudge over something so trivial. I try not to hold a grudge period; it would be a waste of energy.
Yes, it may have come over a bit harsh; I've expurgated it now. But it wasn't aimed at you personally. It's just that sometimes I get fed up with always that same BS of 'measuring' losses and then adding them, so spoiling a good measurement.

[TZ350]

Ok I got the chance tonight to find out what went wrong on the dyno last night.

254567 254568

Blown head gasket ("O" ring) as I suspected.

254570 254569

The piston has been just touching the head

254571

The piston itself looked good and the ring was still free in the grove.

254566

The culprit is the hand made gasket on the right, it compressed down to much, I expect its compressability allowed the combustion pressure to spit the "O" ring out. I replaced it with an alloy plate which should give a more reliable stack for setting the squish clearance and give something more solid for the head to pull up against.

[husaberg]

They say the second thing to go is the memory, and I can't remember what the first thing was. Honestly Husaberg, I cannot recall that question. I either missed it or it was something I could not answer for one reason or another. That may be quite a while. But the idea is so simple; build one yourself. In fact that would be much easier than building a conventional cylinder.
In a conventional jug you need five differently-shaped transfer ducts; in my system you need only one shape, six times. And you need one bridged exhaust duct, twice. Don't you love symmetry?

Yes i do love the idea so logical and elegant in afterthought for me Genius in forethought for you.But
I don't believe NZ has a foundry capable to doing that now, or that would be willing to do it as a one off.
Plus Wob has to eat.


Some more light able to be shed on this tasty little Italian Aprilia esp the semi active suspension. 1992

Another question was to do with the Dellorto carbs.
Were other carbs tried or were the Dellottos better suited to the Disk valve engine or were there other considerations.
Such as their Italianess or sponsorship (I see there is a sponsor sticker on the fairing) or just as case of sticking with what the team was familiar with.
One last thing was that you mentioned in the pit lane thread about the electric power-jet when did Aprilia implement this?. You also mentioned about a car solenoid or stepper motor. A Fiat Uno one why did you go to a Keihin part.
Click on the post it will take you there.
To read the articles clearly click again when the attachment comes up you will see a plus sign click on the and it zooms in.

[TZ350]

I get fed up with always that same BS of 'measuring' losses and then adding them, so spoiling a good measurement.

Thanks, I am a bit new to this EngMod2T simulation and dyno lark and have been trying to figure out how to use them both constructivly.

The graphing of a real world measurement with "correction" was to see how my efforts were stacking up against the simulation, not very well as it turned out and I have to look for the reasons.

[TZ350]

Tonights dyno effort ....

254573

OK so now we have joined the 30RWHP Club

254572

Red Line is a 150mj and the Blue Line a 120, everything else was the same. I am not sure what is going on here but it looks like the Blue line is lean in the lower rpm range, maybe need to look into a power jet arrangement.

254574

Blue Line my 30hp compaired to Speedpros Red Line. Mine is short on power spread compaired to Speedpros but if I can get the bottom end back then it should be a fairly good ride.

Power Jet and a bit of a fiddle with the ignition next.

[Yow Ling]

Hi Frits, just for the record could you confirm the intention of the FOS cylinder is for non competition purposes, of course you can change your mind later. It may help clear a path caused by onerous rules in the future sometime

Thanks
yow ling

[Frits Overmars]

... what i think TZ is trying to do is get the sim to match the Dyno. To do that he needs to acturatly establish the crank HP. He want to get it as close as pos.I can understand that. What I would do: assume a 5 % power loss for every set of gears, for the chain, and for the deformation of the tire on the drum.So what you would measure, is 0.95 (primary drive) * 0.95 (gearbox) * 0.95 (chain) * 0.95 (tire) * crankshaft HP = 0.8145 * crankshaft HP. Or, the other way around: crankshaft HP = drum HP / 0.8145.
Granted, this is not exact, but it's an honest approximation. In any case it is way better than calculating with coast-down losses that you know are not representative of the real losses.
hopefully you noted I spoke of drum HP. That is not the same as rear wheel HP. About 5% of rear wheel HP is lost between tire and drum and what really accelerates the drum, is drum HP. And something which you may not know: Dynojet-readings are already compensated for this loss, and then some. We once did a comparative test at Ten Kate's (umpteen times Supersport world champion, just around the corner from my house). It turned out that the Dynojet is 11% optimistic.

[husaberg]

I can understand that. What I would do: assume a 5 % power loss for every set of gears, for the chain, and for the deformation of the tire on the drum.So what you would measure, is 0.95 (primary drive) * 0.95 (gearbox) * 0.95 (chain) * 0.95 (tire) * crankshaft HP = 0.8145 * crankshaft HP. Or, the other way around: crankshaft HP = drum HP / 0.8145.
Granted, this is not exact, but it's an honest approximation. In any case it is way better than calculating with coast-down losses that you know are not representative of the real losses.
hopefully you noted I spoke of drum HP. That is not the same as rear wheel HP. About 5% of rear wheel HP is lost between tire and drum and what really accelerates the drum, is drum HP. And something which you may not know: Dynojet-readings are already compensated for this loss, and then some. We once did a comparative test at Ten Kate's (umpteen times Supersport world champion, just around the corner from my house). It turned out that the Dynojet is 11% optimistic.

Thanks Frits I had been reading about them the other day on Burgerman he is a bit scathing of them as well.
http://www.dynamometer-info.co.uk/power-losses-flywheel-BHP.htm
Plus another i was on today said just what you said. I note the Bosche Inertia Dynos has two drums and the main drum is twice the weight of the dyno jet.

At the end of the day any time i guess if you estimate one part it could throw out all the accurate work made before hand.

But then again he could always as you say test the hp at the crank and then the output on the Dynojet.

[TZ350]

We once did a comparative test at Ten Kate's (umpteen times Supersport world champion, just around the corner from my house). It turned out that the Dynojet is 11% optimistic.

So, are you saying that I don't need to mark up our DynoJet reading to compare it to the simulation? That could be depressing.

[Frits Overmars]

So, are you saying that I don't need to mark up our DynoJet reading to compare it to the simulation? That could be depressing.Life's a bitch,TZ. But here is some mathematical Prozac for you: drum HP = Dynojet HP / 1.11 and crankshaft HP = drum HP / 0.8145. So crankshaft HP = 1.106 * Dynojet HP. And don't bother about those decimals; after all it is an approximation. So it would be safe to say that crankshaft HP = 1.1 * Dynojet HP.

[TZ350]

... it is an approximation. So it would be safe to say that crankshaft HP = 1.1 * Dynojet HP.

Great Thanks,

Dynojet HP = 30

1.1 * 30 = 33

33 crankshaft HP (approximatly)

Ohhh well, its not quite the 36+ of the simulation with the RS pipe but there are a few more things to try yet.... :D

[Frits Overmars]

Were other carbs tried or were the Dellottos better suited to the Disk valve engine or were there other considerations. Such as their Italianess or sponsorship (I see there is a sponsor sticker on the fairing) or just as case of sticking with what the team was familiar with.
One last thing was that you mentioned in the pit lane thread about the electric power-jet when did Aprilia implement this?. You also mentioned about a car solenoid or stepper motor. A Fiat Uno one why did you go to a Keihin part.When Jan Thiel was developing the Derbi DRVE (now known as the Aprilia RSA125) it turned out that with the engine in the frame the carb was tilted too far forward.
Jan then tried a Keihin that could cope better with the tilt-angle. But there was a contract with Dellorto...
I do not recall the exact date that the electronic power jet was first used. Must have been after Witteveen left the building at the end of 2004 (when he realised that he would be losing Jan Thiel to then-rival Derbi) because Witteveen was always opposed to the powerjet even though Jan Thiel had been asking for it for ages.
The first powerjet version had a stepper motor borrowed from a Fiat Uno where it used to govern idle rpm. In the Dellorto it operated a needle valve.
It was later superseded by a Keihin solenoid valve. Keihin just used it as an open/close valve but with some electronics of their own Aprilia turned it into a pulsating valve (13 Hz). The picture shows those Keihin valves on Simoncelli's Gilera RSA250.

[Yow Ling]

So how much mass do we need in a drum for an inertial dyno for up to say 40hp engines?
would a couple of Petter diesel flywheels do the job ?

[wobbly]

You have to be careful when using the sim as a predictor of actual power.
You see even using the scavenging model of a RS125 isnt strictly accurate, as the GP has a huge A port and small B,C.
The axial up angles may be the same but I doubt the scavenging and or trapping efficiency are equal.
If you reduce the combustion efficiency a few % then you will get alot closer to reality.

The other issue is that to do what you are trying to do properly, you seriously need to plot egt against rpm on the dyno..
If you get such a huge difference in power by changing the main, then it was well wrong in the first place.
And yes, an electronic powerjet will add at leat 800 rpm of free power to that graph, if switched correctly with the right jet ratios - blowing Speedpro of the planet, unless of course he does what I told him.

[Frits Overmars]

when are the FOS cylinders going to be available in a 50mm bore?
That may be quite a while. But the idea is so simple; build one yourself. In fact that would be much easier than building a conventional cylinder. In a conventional jug you need five differently-shaped transfer ducts; in my system you need only one shape, six times. And you need one bridged exhaust duct, twice. Don't you love symmetry?
Yes i do love the idea so logical and elegant in afterthought for me, Genius in forethought for you. But I don't believe NZ has a foundry capable to doing that now, or that would be willing to do it as a one off.What is wrong with a hand job? Several of my acquaintances are carving such a cylinder out of a lump of aluminium. If they can do it, so can you.

[Kickaha]

.But
I don't believe NZ has a foundry capable to doing that now, or that would be willing to do it as a one off.
.

A friend of mine made a pair of cylinders to take a TZ250 V twin out to 350 I have seen the cylinders but can't remember how they made them, I will find out

[Grumph]

A friend of mine made a pair of cylinders to take a TZ250 V twin out to 350 I have seen the cylinders but can't remember how they made them, I will find out

If it's the one i know about, the barrels were bored and linered. these days you'd bore them and re nicasil them. I built the pipes for that one.

There used to be a few foundries here of high enough quality. Not many remain. Talking to Mo Haley today the subject of foundries came up and he recommends the guy in Nelson who does TT Industries gearbox shells. Best work he's seen in NZ.

[husaberg]

What is wrong with a hand job? Several of my acquaintances are carving such a cylinder out of a lump of aluminium. If they can do it, so can you.
WOW

A little bit flasher than i imagined love the curves.:drool:
refresh my memory what the estimated output was per liter and rev range.

Although i think your aquantances are a little more skilled than i am.

Remember i am the guy who put a dellorto slide in backwards on a mineralli once.:facepalm:
I am still messing around with cardboard a protractor vernier a paper cup a piece of pvc and a bit of clay for the offset question you made me try and solve myself.
Getting some er...interesting results. Bloody geometry who would of thought it could be useful in real life.:(

[diesel pig]

It was later superseded by a Keihin solenoid valve. Keihin just used it as an open/close valve but with some electronics of their own Aprilia turned it into a pulsating valve (13 Hz). The picture shows those Keihin valves on Simoncelli's Gilera RSA250.

What is the advantage of pulsating the valve? actual I am very interested how power valves are used on modern two strokes, I understand that the ignition timing has to be changed to get the best from the system.

[Frits Overmars]

What is the advantage of pulsating the valve? actual I am very interested how power valves are used on modern two strokes, I understand that the ignition timing has to be changed to get the best from the system.Imagine the valve passes 60 cc of fuel per minute, but the engine only needs 30 cc. How would you go about that? You could open the valve for 30 seconds and then shut it, but by that time the engine may have drowned.
Open it for one second, close it during one second, open it for one second, sounds more sensible, doesn't it? That is why I quoted the valve's frequency: 13 Hz.
That means it can open and close up to 13 times per second. This again means it could open for 1/13 of a second and close the rest of the second, or open for 12/13 of a second and close during 1/13 s, or everything in between. And of course it can stay completely open or closed; enough possibilities to govern the mixture.

The ignition timing does not have to be changed when you use an electronic power jet. But both the ignition timing and the powerjet timing are means of influencing the exhaust gas temperature. A late ignition and/or a lean mixture both cause a higher EGT, so you can match the exhaust resonance frequency to a rising engine rpm.
And if you have that power jet available, the ignition does not have to do it all by itself anymore, so you can search for a timing that gives a better overall result.

[TZ350]

If you get such a huge difference in power by changing the main, then it was well wrong in the first place.
And yes, an electronic powerjet will add at least 800 rpm of free power to that graph, if switched correctly with the right jet ratios - blowing Speedpro of the planet, unless of course he does what I told him.

The big main was wrong at the top but good in the midrange.

The way the carb has been modified it has greatly increased the signal strength at the main jet. It will take full throttle at about 5000rpm and run all the way out to 13,000 and has cleaned up the area that I made the flappy valve thing for, but don't need it now with this carb.

If I can richen up the mid range I hope to get the mid range power back. But just fiddling with the needle won't do it so I guess an adjustable needle jet from a model aero engine for the power jet adjustment and some way of turning the fuel flow off at higher rpm will be the go.

Because I have an RGV air solenoid, for turning the fuel off to the PJ I am thinking of having a "T" in the power jet fuel line and opening that to atmosphere to kill (stop) the bell mouth vacuum thats drawing the fuel up to the PJ thereby effectivly turning the PJ off.

[Frits Overmars]

To give you an idea of the main jet / power jet ratio: typical RSA-values are main 220, power 120. That means the flow area of the power jet is about (120/220)^2 = 0.3 times the flow area of the main jet. And don't shut the power jet until well past the rpm of maximum power or you will risk a maximum seizure.

[speedpro]

.3 is a large portion of fuel supply to be turning off. I thought it would be a lot smaller like 5% maybe. Or does the valve get pulsed? They use that technique of pulsing a valve to vary boost on turbo engines.

[Frits Overmars]

And now for something completely different: I happened to notice this erection sign ^ . I went back a couple of pages to check and almost everybody appears to have it, except 2T Institute and Grumph. But neither of them are Sheilas, are they? What's the meaning of this?

[Frits Overmars]

.3 is a large portion of fuel supply to be turning off. I thought it would be a lot smaller like 5% maybe. Or does the valve get pulsed? They use that technique of pulsing a valve to vary boost on turbo engines.Yes, the power jet flow is turned off gradually. And no need to ask for the rpm/flow graph; I do not have it at hand here at home in Holland.

[husaberg]

And now for something completely different: I happened to notice this erection sign ^ . I went back a couple of pages to check and almost everybody appears to have it, except 2T Institute

2t institute is a Aussie you will have to post a pic of one of a farm animal.:clap:
Sorry in advance 2T. Thats for the "why is there so few trees in the south island" jibe yesterday he asked if it was "because it is too cold."

yes the symbol means a bloke and they both allegedly are. They possibly are shy, or uncommitted?:lol:
Most likely they didn't fill it in as they didn't notice it.

Ps i noticed on the Rumi engine the FCR carb. Any hp advantage or just suited as it was a downdraft?
Also the Uno carb solenoid was unable to be pulsed is that correct?

[dinamik2t]

Hi guys, happy new year! :)
You have posted very interesting stuff in the last few pages.

My tuning has nothing to do with your races, but I hope my thoughts can be a good influence.
I used to have a manual powerjet Lectron 34 carb and an Ignitech CDI-P unit, which I put on sale last year (not too distant a time :rolleyes:).
I managed to sell them and bought a nwe carb and the Race unit of Ignitech, able to control a TPS and a PJ.
TO be honest, I cheated a little on the carb choise: I had searched once for wobbly in ebay and checked his purchases. There I found the YZ/KX250 Keihin 38 carb, which is about 1cm shorter than conventional PWK, has a TPS sensor and an electronic PJ! Actually, this carb is more similar to their PWM design, I don't know why they named it PWK. Perhaps "k" brand is more established in the community... Anyway.

Here it is:
254605254604

With its shorter length, I can properly tune inlet length according to Wobbly's advices, at 135mm total, using a 30mm manifold and achieve falling case pressure over rising inlet at the 3rd harmonic! Furthermore, as I measured my case comp ratio at ~1.3, it performs better than the 'small' 34 carb!
It's powerjet solenoid says "Shindengen". I don't know whether it's the same one with rsa's.

254606

I assume that with Ignitech I can only control open/close state over RPM. No pulsating operation as Frits explained above.
Now, I have a question.. Ok, in GP's there's the pulsed PJ. I can only choose where to open/close it and Ignitech supports up to 4 power outputs. The first thing that comes in my mind is to add a second powerjet/solenoid to gain more control over the mixture.
Would that be futile?? Left aside corrections, there is only one point to big-lean mixture and gain EGT/power (at overrev), but if I could bo it more gradually would it better?
Perhaps it would be very troublesome to tune in the end...

As for EndMod now..
Not of importance, but here is the curve I have so far from my 118cc engine. I am somehow pipe-limited, so top-power rpm can't rise any further.
This is pretty much my limit, before detonation. I cannot find any way to improve power with this setup.

254607

It only remains to see whether I can properly tune the mixture to get this power and see how much loss there is.

And now it comes to TZ's results. I believe that the difference in crank and RW power might not be a product of the sim's inaccuracy, but perhaps one of the input data or user predicted input data used for the sim. Such as the Comb. Efficiency, as Wobbly said!
I was once very intrigued by that SAE paper "Simulation of a two-stroke". All those sensors on the pipe.. I love sensors! What a room to be in!
Back in 2011, I also thought that I could do my own testing for some of the sim inputs, mostly temperatures and afr. Use sensors to monitor those variables. For me, it is out of curiosity or passion or whatever, but since you guys RACE, you could do it and use it professionaly! Plus, you have your own dyno!

What I had in mind is this:
I obsiously needed a lambda sensor and an EGT sensor. I got both at low prices from ebay. I might add a couple of temp sensors for head/cylinder monitor in the future too.
Now, I know a few stuff of electronics and both the EGT sensor and the lambda** sensor (or any other sensor), that works with the bikes' CDI, produce voltage signals.
So what I need is a unit to record those signals. That unit is called DAQ in electronics, ie data acquisition. Obviously I also need the proper function to translate voltage data to usable afr ratio or temp values. The second one is no problem, I found over the net. The DAQ, I found some units on ebay too, but my income was short this month to purchase this one too :P
Here's a couple of them:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p3984.m1436.l2649&item=320782593160&viewitem=&sspagename=STRK%3AMESINDXX%3AIT#ht_3168wt_1270
http://www.ebay.co.uk/itm/USB-I-O-Data-Acquisition-DAQ-12bit-ADC-PWM-DAC-SPI-UART-TIMERS-Virtual-Port-/200694789535?_trksid=p4340.m185&_trkparms=algo%3DDLSL%252BSIC.NPJS%26its%3DI%26itu %3DUCI%252BUA%26otn%3D10%26pmod%3D200690567499%252 B200690567499%26po%3D%26ps%3D63%26clkid%3D54168057 74014924958#ht_651wt_1037

And here's a cheap o2 sensor (they also have with 2/3/4 wires):
http://www.ebay.com/itm/New-DENSO-Universal-O2-Oxygen-Sensor-1-Wire-234-1000-/400232715508?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%252BC%26itu%3D UA%26otn%3D5%26pmod%3D260906582323%26ps%3D63%26clk id%3D5416825633487504366#ht_500wt_1054

Ah, forgot to mention. Last month I also found a great deal of 4 NGK 6254E plugs from KX125 and one 7376! The second one has a significantly thinner ground/side electrode compared to the KX ones!
And they both have very thick washers compared to conventional B-plugs. Or is it threaded length? I haven't really measured.:(

254609



** I wonder why there is the B between 'a' and 'd'.. The word describes the greek letter for L, which we pronounce lamda. No b!
And sorry, huge post!

[2T Institute]

And now for something completely different: I happened to notice this erection sign ^ . I went back a couple of pages to check and almost everybody appears to have it, except 2T Institute and Grumph. But neither of them are Sheilas, are they? What's the meaning of this?

It flags who's been purchasing Viagra online.:girlfight:

[2T Institute]

2t institute is a Aussie you will have to post a pic of one of a farm animal.:clap:
Sorry in advance 2T. Thats for the "why is there so few trees in the south island" jibe yesterday he asked if it was "because it is too cold."

yes the symbol means a bloke and they both allegedly are. They possibly are shy, or uncommitted?:lol:
Most likely they didn't fill it in as they didn't notice it.

Ps i noticed on the Rumi engine the FCR carb. Any hp advantage or just suited as it was a downdraft?
Also the Uno carb solenoid was unable to be pulsed is that correct?

Stray dogs would have go a long way to find a tree to piss on ! Was a serious question BTW :lol:


Dynos, I look for a flat as torque curve possible with the power roughly a 45deg line upwards hold peak for as long as possible and 45deg down on the over rev. Makes it an easy bike to ride fast. All has to match the gearbox though

Dyno v's Sim, even with the rickety old Mota sim the shapes of the curves matched which told me the data I input was correct, With EngMod if you can expect sim -15% that's s hell of a good start, if you don't get that look jetting and ignition.

[Frits Overmars]

Ps i noticed on the Rumi engine the FCR carb. Any hp advantage or just suited as it was a downdraft?
Also the Uno carb solenoid was unable to be pulsed is that correct?Your yellow text makes me think you chose a dark background, huh? Mine is white; thanks for the headache :eek5:.
Yes, the FCR carb was chosen because it enabled us to use a dead straight inlet tract on the Rumi engine.
The Fiat Uno unit was not a solenoid; it was a stepper motor; a rotating device. And stepper motors only function when pulsed.

[dinamik2t]

The Fiat Uno unit was not a solenoid; it was a stepper motor; a rotating device. And stepper motors only function when pulsed.

254612

It's like this I imagine..
Lots can be found under the name 'idle control valve' (not necessarily fiat).

[Frits Overmars]

Lots can be found under the name 'idle control valve' (not necessarily fiat).When in Italy.....
Makes me wonder: what automotive industry have you guys got in NZ?

[dinamik2t]

Eh, yes. Obviously Aprilia used Fiat's due to nationality. I would proudly do exactly the same!
I wanted to point out that one shouldn't search solely for a fiat motor, as there are also renault, mitsubishi, rover etc etc. And italians' are a little spicy in prices. <_<

[Grumph]

When in Italy.....
Makes me wonder: what automotive industry have you guys got in NZ?

Not a lot now...Plenty of reconditioners though.

Re the symbol Frits...as i've said, I'm old...there wasn't a droop option available.

[Frits Overmars]

Re the symbol Frits...as i've said, I'm old...there wasn't a droop option available.The devil is old, Grumph.
I was warned that once you're past 50, you can expect erection problems. I'm 63 now and I can confirm: down boy, down!

[husaberg]

I assume that with Ignitech I can only control open/close state over RPM. No pulsating operation as Frits explained above.
Now, I have a question.. Ok, in GP's there's the pulsed PJ. I can only choose where to open/close it and Ignitech supports up to 4 power outputs. The first thing that comes in my mind is to add a second powerjet/solenoid to gain more control over the mixture.
Would that be futile?? Left aside corrections, there is only one point to big-lean mixture and gain EGT/power (at overrev), but if I could bo it more gradually would it better?
Perhaps it would be very troublesome to tune in the end...

As for EndMod now..
Not of importance, but here is the curve I have so far from my 118cc engine. I am somehow pipe-limited, so top-power rpm can't rise any further.
This is pretty much my limit, before detonation. I cannot find any way to improve power with this setup.



What I had in mind is this:
I obsiously needed a lambda sensor and an EGT sensor. I got both at low prices from ebay. I might add a couple of temp sensors for head/cylinder monitor in the future too.
Now, I know a few stuff of electronics and both the EGT sensor and the lambda** sensor (or any other sensor), that works with the bikes' CDI, produce voltage signals.
So what I need is a unit to record those signals. That unit is called DAQ in electronics, ie data acquisition. Obviously I also need the proper function to translate voltage data to usable afr ratio or temp values. The second one is no problem, I found over the net. The DAQ, I found some units on ebay too, but my income was short this month to purchase this one too :P
Here's a couple of them:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p3984.m1436.l2649&item=320782593160&viewitem=&sspagename=STRK%3AMESINDXX%3AIT#ht_3168wt_1270
http://www.ebay.co.uk/itm/USB-I-O-Data-Acquisition-DAQ-12bit-ADC-PWM-DAC-SPI-UART-TIMERS-Virtual-Port-/200694789535?_trksid=p4340.m185&_trkparms=algo%3DDLSL%2BSIC.NPJS%26its%3DI%26itu%3 DUCI%2BUA%26otn%3D10%26pmod%3D200690567499%2B20069 0567499%26po%3D%26ps%3D63%26clkid%3D54168057740149 24958#ht_651wt_1037

And here's a cheap o2 sensor (they also have with 2/3/4 wires):
http://www.ebay.com/itm/New-DENSO-Universal-O2-Oxygen-Sensor-1-Wire-234-1000-/400232715508?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%2BC%26itu%3DUA %26otn%3D5%26pmod%3D260906582323%26ps%3D63%26clkid %3D5416825633487504366#ht_500wt_1054


And sorry, huge post!

Don't know if this helps but this is a pulse circuit.
Speedpro was mentioning something similar
http://www.jaycar.com.au/productView.asp?ID=KC5384&keywords=pulse&form=KEYWORD

(http://www.jaycar.com.au/productView.asp?ID=KC5384&keywords=pulse&form=KEYWORD)

[Grumph]

The devil is old, Grumph.
I was warned that once you're past 50, you can expect erection problems. I'm 63 now and I can confirm: down boy, down!

And do you attribute that to two strokes ? - just to try to bring the thread back on track you understand....

[TerraRoot]

all these talks of solenoids and power jets perhaps a simple EFI system would be better?

http://www.mbe-motorsports.com/catalog/product_info.php/cPath/22/products_id/337

http://www.ecotrons.com/2_Stroke_Small_Engine_EFI_kit.html

http://www.ecotrons.com/website/2T_EFI_Kit_mid.jpg

[explode64]

all these talks of solenoids and power jets perhaps a simple EFI system would be better?

http://www.mbe-motorsports.com/catalog/product_info.php/cPath/22/products_id/337

http://www.ecotrons.com/2_Stroke_Small_Engine_EFI_kit.html

http://www.ecotrons.com/website/2T_EFI_Kit_mid.jpg



There is a current discussion on ekartingnews about EFI 2T http://ekartingnews.com/viewtopic.php?t=110370&postdays=0&postorder=asc&start=75
They have a pic of a CR500. Some guys are creating their own using known fuel distribution curve and neediel/tube graphs as a guide for fuel flow.

[husaberg]

There is a current discussion on ekartingnews about EFI 2T http://ekartingnews.com/viewtopic.php?t=110370&postdays=0&postorder=asc&start=75
They have a pic of a CR500. Some guys are creating their own using known fuel distribution curve and neediel/tube graphs as a guide for fuel flow.

Its a big one sorry all this talk of piggy back circuits.
These curcuits can also be used in numerous ways partically like a couple of them.

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if !mso]><object classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui></object> <style> st1\:*{behavior:url(#ieooui) } </style> <![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]-->
Refer: Silicon Chip January 2007 This kit stops the air conditioner in your car from taking engine power when accelerating such as when you're overtaking or going up a hill. It automatically switches the air conditioner's compressor off when the engine is at a high throttle setting and will allow the compressor to run with low throttle even when the cabin temperature setting has been reached. It also automatically switches the compressor off at idle. When the throttle position is normal the compressor will operate normally. The kit features an override switch, an LED function indicator and is supplied with PCB with overlay and all electronic components. > Recommended box UB3 HB-6013.
http://www.jaycar.com.au/productView.asp?ID=KC5437&CATID=76&form=CAT2&SUBCATID=965#11
<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]-->

This kit operates a relay when a preset temperature is exceeded and drops-out the relay when temperature drops. The relay included is capable of switching small currents only, so a larger relay or switching device should be employed if switching mains voltages or heavy currents. Ideal as a thermostat, ice alarm, hydroponics applications, etc. A small trimpot is used to adjust the cutout temperatures for the relay in the range of approx -30 to +150 degrees celcius. €Kit includes NTC thermocouple.

http://www.jaycar.com.au/productView.asp?ID=KG9140&CATID=76&form=CAT2&SUBCATID=965#11


<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]-->


http://www.jaycar.com.au/productView.asp?ID=KC5424&keywords=auto&form=KEYWORD
http://www.jaycar.com.au/productView.asp?ID=KC5378&CATID=76&form=CAT2&SUBCATID=965#11
http://www.jaycar.com.au/productView.asp?ID=KC5195&keywords=auto&form=KEYWORD
http://www.jaycar.com.au/productView.asp?ID=KC5435&keywords=auto&form=KEYWORD
http://www.jaycar.com.au/productView.asp?ID=KC5442&keywords=auto&form=KEYWORD
http://www.jaycar.com.au/productView.asp?ID=XC4226&CATID=76&form=CAT2&SUBCATID=965#11
http://www.jaycar.com.au/productView.asp?ID=KC5443&keywords=auto&form=KEYWORD
http://www.jaycar.com.au/productView.asp?ID=KC5376&CATID=76&form=CAT2&SUBCATID=965#11
http://www.jaycar.com.au/productView.asp?ID=KC5485&CATID=76&form=CAT2&SUBCATID=965#11
http://www.jaycar.com.au/productView.asp?ID=KC5377&CATID=76&form=CAT2&SUBCATID=965#11
http://www.jaycar.com.au/productView.asp?ID=KC5444&CATID=76&form=CAT2&SUBCATID=965#11


I mentioned 555 curcuit earlier. Most sensors give output in voltages 1-5 volts something along the lines below will enable a sensor to say pulse a powerjet?

One of the most fundamental problems in robotics is DC motor speed control. The most common method of speed control is PWM or pulse width modulation. Pulse width modulation is the process of switching the power to a device on and off at a given frequency, with varying on and off times. These on and off times are referred to as "duty cycle". The diagram below shows the waveforms of 10%, 50%, and 90% duty cycle signals.

As you can see from the diagram, a 10% duty cycle signal is on for 10% of the wavelength and off for 90%, while a 90% duty cycle signal is on for 90% and off for 10%. These signals are sent to the motor at a high enough frequency that the pulsing has no effect on the motor. The end result of the PWM process is that the overall power sent to the motor can be adjusted from off (0% duty cycle) to full on (100% duty cycle) with good efficiency and stable control.
While many robot builders use a microcontroller to generate the required PWM signals, the 555 PWM circuit explained here will give the novice robot builder an easy to construct circuit, and good understanding of pulse width modulation. It is also useful in a variety of other applications where the PWM setting need only be changed occasionally.
The 555 timer in the PWM circuit is configured as an astable oscillator. This means that once power is applied, the 555 will oscillate without any external trigger. Before the technical explanation of the circuit, let's look at the 555 timer IC itself.



http://www.dprg.org/tutorials/2005-11a/index.html

[wobbly]

PWM control of the powerjet is a very sexy use of technology,slowly ramping off the fuel flow against rpm, but in reality using a simple rpm controlled switched solenoid work perfectly fine.
Yamaha and Honda have used the switched powerjet since forever, its reliable and does the job.
Only issue you need to address is the jet size and switch point ( along with TPS value ).
Running Avgas as we are still allowed to do, means that the tuning is based around getting high egt numbers to create good power, with lots of com and advance - unleaded is the opposite..
Thus experience has shown that as leaded fuel works best with a lean condition at peak power, we only need to switch a small jet just past peak - to increase the pipe temp and
thus give better overev.
In the Keihin numbering this is in mm dia and switching off a .35 is perfect.
When running unleaded, as the GP bikes have for years, the fuel likes to be rich at peak to create the best power, thus we need to switch off alot of fuel flow to increase the pipe heat quickly enough.
In this case a .65 is needed to do the job.
On the dyno or on the track it is easy to tell if the switch point is a little too low, as it feels exactly like the bike has changed into another gear past 6th.
It jumps forward when the solenoid kicks in - making the fuel curve lean, too early.Do this enough - and bang.
Its critical to 100rpm, and is working perfectly when you dont feel it happen - the power just keeps going.
To do it on the dyno you have to run the bike in 6th to simulate the acceleration rate as seen in that gear on the track, and is easy to do running back to back run ups.
Changing the rpm number 100 at a time, lower in the Ignitech, reprogram on the fly and run again.
If the rpm is too high - nothing happens, as there isnt time for the heat to affect the pipe wave speed.

[husaberg]

PWM control of the powerjet is a very sexy use of technology,slowly ramping off the fuel flow against rpm, but in reality using a simple rpm controlled switched solenoid work perfectly fine.
Yamaha and Honda have used the switched powerjet since forever, its reliable and does the job.
Only issue you need to address is the jet size and switch point ( along with TPS value ).
.

Right i had a wee search on the net.
The genuine kit is a little expensive, I couldn't find the Keihin but here is the Mikuni, as you know i had already posted this.$303nz.
Maybe the Keihin kit is less expensive.

I haven't had the chance to look through Sudco yet.
Had a wee look at Sudco it seems the soilniod is not listed as a separate part bugger.

Here is one from the UK Mikuni person no prices.
http://www.allensperformance.co.uk/products-power jet kits.html

I also found this with the dimensions of a lot of inlet manifolds etc
http://www.allensperformance.co.uk/products-manifolds.html

TZ's keihin copy carbs i believe have a Powerjet the obvious way to me for a budget conscious bucket racer would be to modify this for electric use with a car solenoid.

There is another option but i am not posting that until i have got one myself.

[TZ350]

The Fiat Uno unit was not a solenoid; it was a stepper motor; a rotating device. And stepper motors only function when pulsed.

254658

It's like this I imagine..
Lots can be found under the name 'idle control valve' (not necessarily fiat).

If its a stepping motor then it could be controled by Ignitec's power valve controler.

[husaberg]

If its a stepping motor then it could be controled by a Ignitec's power valve controler.

Nice explantion on powerjets here no that theres anything wrong with wobs.
http://superkartaus.com/Forums/index.php?topic=77.0;wap2

Adjustable powerjet it looks like it would be easy to make as well addthis with an electric controll or just adjust the pulse to your needs as Wob said would be very6 Sexy but prob a bit OTT.

http://www.twostrokeracelab.com/search/label/Adjustable%20Powerjet

The rest of the site is well worth a look as well.

Here is a 12volt solenoid that looks capable assuming there isn't a car wrecker part to suit around.
I have priced the Genuine Mikuni kit a $200 US so it is a tad expensive.
Remember though what ever the set up it has to be so if it fails it will not lean out the mixture.For obvious reasons

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<tbody>
<form> Tubular 12V Solenoid

Compact size, Push type.- Coil resistance 25.6- 20 watt @ 25% duty cycle.- Pushing force 220 - 940g (25% duty cycle).- Stroke 1.0 - 6.0mm (25% duty cycle).- Total weight 23g.- Full data supplied with unit.

</form>

<tbody>

QTY




1+
$41.90



5+
$37.90



10+
$33.40

</tbody>



</tbody>


http://www.jaycar.co.nz/productResults.asp?MID=1&SSUBID=730&SUBCATID=983&keyform=CAT2

Of course if stepper motors are more your deal there is this.

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12VDC 48 Step / 7.5° Stepper Motor

• Standard 48 step / 7.5° design.
• Flange mount 3.0mm hardened steel shaft.

Specifications:
• Rated voltage: 12VDC
• Rated current: 1.1A/phase
• Phases: 4
• Steps per revolution: 48
• Stepping angle: 7.5°
• Drive method: Unipolar chopper drive
• Resistance per winding: 20 ohms
• Starting frequency: 600pps (max)
• Holding torque: 700g/cm

<tbody>

QTY




1+
$23.90



5+
$21.30



10+
$18.90

</tbody>


http://www.jaycar.co.nz/productView.asp?ID=YM2754&keywords=12v+stepper+motor&form=KEYWORD

[Yow Ling]

If its a stepping motor then it could be controled by Ignitec's power valve controler.

I thought the Ignitech PV controller was for DC servo motor not a stepper , Ill have too check now

[TZ350]

I also found this with the dimensions of a lot of inlet manifolds etc
http://www.allensperformance.co.uk/products-manifolds.html


Inlet manifold data, pure gold ... just what I was looking for, thanks.

[TZ350]

I thought the Ignitech PV controller was for DC servo motor not a stepper , Ill have too check now

you are right ... :blink: just checked "brush servo motor"

[2T Institute]

Suzuki RGV/Aprilia RS 250's (along with NSR/TZR's) have emissions air soleniods fitted to the pilot and main air corrector circuits. With an Ignitech or Zeeltronic you can trim the fuel by adding air to extend over rev. Beats changing jets.

[TerraRoot]

There is a current discussion on ekartingnews about EFI 2T http://ekartingnews.com/viewtopic.php?t=110370&postdays=0&postorder=asc&start=75
They have a pic of a CR500. Some guys are creating their own using known fuel distribution curve and neediel/tube graphs as a guide for fuel flow.

thats a great thread, loving some of the info the HGT guys give out.

here another one with the ecotrons:
http://www.scootforum.com/viewtopic.php?f=95&t=710&st=0&sk=t&sd=a&sid=fb2f8400a0719cb17aa6cba9c463c4a0
and another with MS:
http://www.125ccsportsbikes.com/forums/index.php?showtopic=63480&st=0

[2T Institute]

Seems the only info HGT gives out is "...........for 31yrs I was a GM engineer..........."

BRC (make Rotax 256 copy kart engines) Riley Will (who contributed to the pitlane.biz RSA thread) spoke the most sense there


The 2002 500cc bikes used 35-36mm carbs with electronic solenoid type power jets.

KTM used a hybrid system where they used an injector to augment the fueling requirements. It was used in their 250cc program, but I'm not 100% sure if they used it in the 125cc bike as well. Probably, but I cannot be certain.

Aprilia was guilty of throwing out what they perfected (carburation)and introducing a totally new concept loaded with technology EFI system. It was an intelligent system that made all the theoretical calculations at light speed..... It was a perfect system....... Too perfect! For years 2 stroke engine development was being done using less than perfect carburetor. This includes rider knowledge, tire construction, and suspension..... The end result was that the riders and machinery (tires) couldn't cope with the instantaneous increase in torque when the throttle was opened while at maximum lean angles.

When I discussed how I was going to do my EFI, their main electronics engineer started clapping..... What I wanted to do (and later did) was to upload a fuel distribution curve similar to a Del'Lorto needle/tube (needle jet) combination and did not let the computer adjust it. I used a TPS, H2O sensor, Air temp sensor, and Hall Sensor for crank angle/rpm. This way I was using what I knew, but getting the benefit of 3 bar of fuel pressure and injector atomization. I had total control and could add fuel to make the fuel curve "imperfect" if need be. I used 2 injectors mounted on the engine side of the throttle valve and I alternated their firing so that I could rev upto 15000 rpm. That way each injector was mislead into thinking it was feeding a 7500 rpm max 4 stroke cylinder. In total I invested $1600 into the total system and had it running pulling load on the dyno in 3 hours.


Riley later says he timed the injector to squirt 10deg before inlet open and finish 10deg after inlet close

[TZ350]

254704

Possible cheepish valve $35 buy now on Trademe (NO or NC??? not sure how they work)

http://www.trademe.co.nz/motors/motorbikes/parts-for-sale/other/auction-438243286.htm

[TerraRoot]

Seems the only info HGT gives out is "...........for 31yrs I was a GM engineer..........."



i was referring to the info about what sensors were used and that the MAP system of MS does't agree with two strokes very well. the injector timings and mapping it to make it act like a carb, well thats just your own job, i.e. map it right.

i've a sneaking suspicion that the HGT ecu is quite similar to the ecotrons one.

[Strokerhaus]

The other issue is that to do what you are trying to do properly, you seriously need to plot egt against rpm on the dyno..
If you get such a huge difference in power by changing the main, then it was well wrong in the first place.
And yes, an electronic powerjet will add at leat 800 rpm of free power to that graph, if switched correctly with the right jet ratios - blowing Speedpro of the planet, unless of course he does what I told him.

Interesting I've just got a similar rpm gift and a bhp rise when fitting none power jet Gardners to my old 350 TZ. The odd thing is I have long bell mouths on the carbs, which is not normal practice and it looks like I may have a better bottom end to go with it, but work is still in progress.

[SS90]

254704

Possible cheepish valve $35 buy now on Trademe (NO or NC??? not sure how they work)

http://www.trademe.co.nz/motors/motorbikes/parts-for-sale/other/auction-438243286.htm

That is an automatic enricher for a moped, the two wires allow an internal heater to assist in the melting of the wax (which melts as the engine warms up), closing off the enricher jet, when it cools down (engine and 12v off) the wax solidifies, and allows the spring loaded plunger to push the enricher jet open again.
Been around since about, 1982, 1983 or so.

Not any sort of power jet.:msn-wink:

[husaberg]

Interesting I've just got a similar rpm gift and a bhp rise when fitting none power jet Gardners to my old 350 TZ. The odd thing is I have long bell mouths on the carbs, which is not normal practice and it looks like I may have a better bottom end to go with it, but work is still in progress.

I would be interested to see the airflow results for the Gardners on a flow bench.
You may find they they flow better than a std style carb. Would you post a few pictures for the thread.
I had trouble finding decent pictures of then when i posted something about them.

[Grumph]

That is an automatic enricher for a moped,

Not any sort of power jet.:msn-wink:

Tell that to the poor bugger trying to stay in front of cars on a frosty ChCh morning......Probably the only thing keeping him alive.

Gardener Carbs - very clean intenally, and because of the flatslide design, very sensitive to air speed.
It wouldn't surprise me if they self - enrichened at WOT.

[wobbly]

The only good pic I could find of Gardner.
With the long bellmouth version I can see why a TZ350 would work well,the correct tuned length for peak at 10,000 is near double that of a stock 38mm Mikuni.

http://kioteegarage.blogspot.com/2011/10/flat-slide-history.html

[Strokerhaus]

I would be interested to see the airflow results for the Gardners on a flow bench.
You may find they they flow better than a std style carb. Would you post a few pictures for the thread.
I had trouble finding decent pictures of then when i posted something about them.

I have no airflow data, and once I have worked out how to post a few pictures I will. As was said they are a very clean carb for airflow with a flat slide. They do seem to self adjust for fueling as the air to fuel ratio's compared with the prior Mikuni powerjet reverse slides are similar. Once I have finished the setting up of the carbs I will give you more data, but that will be a few weeks yet.

[TZ350]

Dynos, I look for a flat as torque curve possible with the power roughly a 45deg line upwards hold peak for as long as possible and 45deg down on the over rev. Makes it an easy bike to ride fast. All has to match the gearbox though

254814

Not quite flat and not quite 45 deg but getting there....

125cc Air cooled Rotary Valve with 24mm Carb, 1980 modified Suzuki GP125 commuter bike engine.

[dmcca]

All this talk of PWM solenoids, etc...

Makes me wonder if its possible to do away with the fixed aperture jets all together... run a standard carb setup but instead of a pilot and main run 2 x solenoids (one for each circuit) operated by an ecu which varies PWM signals in response to a wideband input (or pre determined map of rpm vs tps vs temp, etc). Pilot solenoid reaches full duty cycle very early (same as a pilot jet), then main solenoid gradually increases in duty cycle (simulating the opening of the needle) until it also reaches max duty.

Itd be like a variation on the info 2T Institute posted about air correction circuits on RGVs/RSs etc

Essentially just a computer controlled jet size... Would it be a nice halfway measure between a carb and full on efi for a 2 stroke motorcycle?? Im not sure, just an idea.

[wobbly]

It just occurred to me TeeZee that you guys need to feed a free copy of Gadwin printscreen into the dyno computer.
You can save to a file or a printer very easy.

[husaberg]

The only good pic I could find of Gardner.
With the long bellmouth version I can see why a TZ350 would work well,the correct tuned length for peak at 10,000 is near double that of a stock 38mm Mikuni.

http://kioteegarage.blogspot.com/2011/10/flat-slide-history.html

I thought i had posted a pic of them but only a brief description TZ has posted a picture of one with a mattchbox float
But here is one with a bolt on Stack.

Bill Swallow or his brother used to use one on a real fast ohv velo.
Also when the classic movement started again i believe he started to manufacture them.

http://www.flickr.com/photos/slrosko/4636268333/

[TZ350]

It just occurred to me TeeZee that you guys need to feed a free copy of Gadwin printscreen into the dyno computer.
You can save to a file or a printer very easy.

Our problem is the dyno computer is very old, floppy disks, Win 3.2 or something and RS232 communication with the dyno, parallel printer port and we didn't get the original software disks with it. $500 USD to become registered with DynoJet and the the cost of an upgrade package, thats all to expensive for us at the moment.

[TZ350]

All this talk of PWM solenoids, etc...

Makes me wonder if its possible to do away with the fixed aperture jets all together... run a standard carb setup but instead of a pilot and main run 2 x solenoids (one for each circuit) ... Essentially just a computer controlled jet size... Would it be a nice halfway measure between a carb and full on efi for a 2 stroke motorcycle?? Im not sure, just an idea.

Sounds very interesting ...

[husaberg]

Sounds very interesting ...

HRC, Cagiva, Bimota (admittedly direct injection for Bimota) and probably Yamaha spent big dollars (Ie millions) on fuel injection.
The results were a bike that made no more power and was harder to ride. Itohs NSR was faster, but he was tiny compared to Doohan and could tuck in better, also his best race results were on a Carburated bike.
Cagiva said the major benefit of doing it was to allow easy tuning to suit weather and the possibility of a more compact engine design later.
Honda said it would make no more power but had lower fuel consumption and that was their aim. To me an electric carb like a lot of 80s car had for emmisions was the worst of both deigns. just my biased thoughts on the mater. Carbs are cheap, relativity speaking, light and surprisingly efficient on a NA motor.
The biggest advantage i can see with fuel injection is for emissions with a direct injection system.

[2T Institute]

All this talk of PWM solenoids, etc...

Makes me wonder if its possible to do away with the fixed aperture jets all together... run a standard carb setup but instead of a pilot and main run 2 x solenoids (one for each circuit) operated by an ecu which varies PWM signals in response to a wideband input (or pre determined map of rpm vs tps vs temp, etc). Pilot solenoid reaches full duty cycle very early (same as a pilot jet), then main solenoid gradually increases in duty cycle (simulating the opening of the needle) until it also reaches max duty.

Itd be like a variation on the info 2T Institute posted about air correction circuits on RGVs/RSs etc

Essentially just a computer controlled jet size... Would it be a nice halfway measure between a carb and full on efi for a 2 stroke motorcycle?? Im not sure, just an idea.

RGV and RS is close to it, reality is it's there for emmissions not for performance. What your talking abouut is and electronic 'Master Tune' I could envisage this driven by a stepper motor. Zeeltronic is looking at a way of driving the stepper motor with their software.

[2T Institute]

254814

Not quite flat and not quite 45 deg but getting there....

125cc Air cooled Rotary Valve with 24mm Carb, 1980 modified Suzuki GP125 commuter bike engine.

Plot your gearshift points on that and if that falls on the rising part of the torque curve only thing you have to do is buy some decent shocks :headbang:

[husaberg]

Sounds very interesting ...
As interesting as this TZ

http://2stroker.createforumhosting.com/armstrong-motorcyles-t3382.html

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Armstrong worked with Gardner Carbs to develop a combined disk valve cover and flat slide carb assembly, to reduce inlet tract length. I believe there is a working example is in Germany

[Strokerhaus]

I would be interested to see the airflow results for the Gardners on a flow bench.
You may find they they flow better than a std style carb. Would you post a few pictures for the thread.
I had trouble finding decent pictures of then when i posted something about them.

Photo of Gardners 500 series on TZ attached ??? Possibly

254848

[nasone32]

since you are talking about injection... i was reluctant to post here but i thought it might interest someone else...

i just bought an injection kit from ecotrons, i took the cheap way, we'll see if this thing works. It is a cheap construction kit, but the fuel pump and injectors look good and the included program seems made by someone intelligent.
http://imageshack.us/photo/my-images/407/sdc12099copy.jpg/
http://imageshack.us/photo/my-images/847/sdc12098copy.jpg/

i am going to mill my own throttle body after a quick test with the one they sell.

my only purpouse is to try the 24/7 valve idea by Frits. that valve has a huge transition in the jet size requirement, due to the air flow becoming very slow when the valve is opened (working in 24/7 mode), a carb can not cope with this kind of transition.
this very cheap efi kit has a real-time switchable map, that can be used to switch between closed and open valve mode...

(Also, if Mr Overmars is reading: If you are going to join the Continental Championship Race Tech in some way, and you would use a cvt, i would be very glad to sponsor, i have a belt cvt patent with a lot improved efficiency that i would like to show you... won the italian scooter champ this year so it's something already tested extensively)

[F5 Dave]

funny, I was thinking about the 24/7 idea last night as I drove home from the dyno having broken a reed.

Anyway it strikes me that if the concept did work (& the only time I've broken reeds the bike runs dreadfully up top), but either way to continue, if the bike did run ok 24/7 then surely the easiest way rather than this complicated reedblock arrangement; would be to make a round port into the back of the cases with the carb on it much like an RSA without the disc & a simple guillotine that closed it off (like a flat thin slide carb that went to the floor).

Then a 2nd pathetic size reedvalve with a 14mm carb with the same arrangement, but feed into the front of the cases out of the way. This could be used to start it, - then a Frankenstein lever pulled [bwahahahaha!:crazy:] that opens guillotine 1 & closes 2.

[Yow Ling]

funny, I was thinking about the 24/7 idea last night as I drove home from the dyno having broken a reed.

Anyway it strikes me that if the concept did work (& the only time I've broken reeds the bike runs dreadfully up top), but either way to continue, if the bike did run ok 24/7 then surely the easiest way rather than this complicated reedblock arrangement; would be to make a round port into the back of the cases with the carb on it much like an RSA without the disc & a simple guillotine that closed it off (like a flat thin slide carb that went to the floor).

Then a 2nd pathetic size reedvalve with a 14mm carb with the same arrangement, but feed into the front of the cases out of the way. This could be used to start it, - then a Frankenstein lever pulled [bwahahahaha!:crazy:] that opens guillotine 1 & closes 2.

Doesnt really sound complicated enough yet Dave, where are the stepper motors and sensors etc Is there an app we can download so we just run it from the phone.

Maybe 24/7 needs the perfect pipe to work properly

[F5 Dave]

yeah, also in my mind it was the monster pulling the lever, when it should have been Dr Frankenstein or Egor doing the honours. I don't know if this is important.

[TZ350]

yeah, also in my mind it was the monster pulling the lever, when it should have been Dr Frankenstein or Egor doing the honours. I don't know if this is important.

254864

Who???? said we are doing what!!!! at team ESE, how did you know???

254863

Still we will get the recipie right soon.

[TZ350]

254903

OK ... been trying the after carb inline resonator but with an OKO carb, lost HP and was making 26 and less depending on the before carb resonator length.

254873

On the bright side things went back to normall when I put the carb back in its conventional position.

254872

30.40rwhp I picked up some midrange with a bit of jetting and ignition fiddling. I will have another play with the ignition and jetting tomorrow to see if I can pick up any more midrange, then its into making another pipe.

254875

By a bit of clever machining Bucket managed to lose 15mm from the inlet tract length (it was 145mm). We will see how that goes tommorow night.

[wobbly]

That graph looks exactly like what you get by advancing the stator a bit.
More mid, less overev.
Can you now loose some timing past 12,000 to get the overev back.

[nasone32]

I noticed it is possible to simulate 24/7 with engmod2t, you just need to create a disk valve with 180 advance and 180 closing duration. 360° disk=24/7
Engmod is particularly efficient because it keeps a trace of every wave travelling here and there.

You can also play around a lot with crankcase volume, inlet lenght and diameter and see how much a 24/7 is sensitive to these params (an looks very sensitive of course). I played with exhaust pipes also, and looks like a conventional pipe works good, in fact the only way you could modify a pipe would be to thin the power range (and try to make more powerful pulses) but this way pays too much in term of usable range, with little or no gain at top...
also I think that with 24/7 you would like a very broad and long pulse to keep the air as much as possible into the engine, without coming back out from the intake.

[Frits Overmars]

...if Mr Overmars is reading: If you are going to join the Continental Championship Race Tech in some way, and you would use a cvt, i would be very glad to sponsor, i have a belt cvt patent with a lot improved efficiency that i would like to show you... won the italian scooter champ this year so it's something already tested extensively)Hé Nasone, cosa stai facendo su questo forum?
A friend of mine, Martijn Stehouwer (twice european champion classic 50 cc racing in 2009 and 2010) is planning to build a 50 cc racer with CVT transmission for the CCRT series, so we are very interested in your belt. You can get in touch with him via info@emot.nl or via a private message in Pit-Lane.biz.

Regarding the exhaust pipe: the 24/7 system requires nothing out of the ordinary. A pipe that functions well on a 'normal' engine, will do just as well in combination with the 24/7-system, once it is running in the power band.
Like you said: the transition from reed induction to 24/7 may cause carburation problems, and the logical way out is fuel injection.

[TZ350]

i have a belt cvt patent with a lot improved efficiency that i would like to show you... won the italian scooter champ this year so it's something already tested extensively)

I too would be very interested in this transmission. please PM me.

[Frits Overmars]

funny, I was thinking about the 24/7 idea last night as I drove home from the dyno having broken a reed.
Anyway it strikes me that if the concept did work (& the only time I've broken reeds the bike runs dreadfully up top), but either way to continue, if the bike did run ok 24/7 then surely the easiest way rather than this complicated reedblock arrangement; would be to make a round port into the back of the cases with the carb on it much like an RSA without the disc & a simple guillotine that closed it off (like a flat thin slide carb that went to the floor).
Then a 2nd pathetic size reedvalve with a 14mm carb with the same arrangement, but feed into the front of the cases out of the way. This could be used to start it, - then a Frankenstein lever pulled [bwahahahaha!:crazy:] that opens guillotine 1 & closes 2.You can't expect the carburation of a reed bike to remain perfect after the reed breaks, Dave; it will probably have a lot of blow-back and therefore a terribly rich mixture. You'd need to find the right combination of crankcase volume (large!), inlet tract diameter and length for a clean 24/7-carburation.
Which complicated reedblock are you talking about? The one with the two hinged reeds coupled by gears that you may have seen in www.pit-lane.biz (http://www.pit-lane.biz)?
That was the very first prototype, over ten years old now. It was over-engineered all right; just one hinged reed without any gears will do just fine.

What you are suggesting, two carbs, has been tried by a dutch Kreidler tuner: http://kreidler.nl/forum/viewtopic.php?f=5&t=38866 .
He didn't even bother with guillotines or reeds; just the normal piston-ported carb and a second carb connected directly to the crankcase.
In the video the jetting is off and he opens that second throttle way too early but nevertheless the contraption runs....

[2T Institute]

Frits how do the 2 halves of the homemade FOS cylinder stay together?

[Frits Overmars]

Frits how do the 2 halves of the homemade FOS cylinder stay together?I assume you are talking about the two pictures of the Rossi-GRM cylinder I posted last week? I left it to them how they wanted to build it and did not discuss details but I guess the parts are simple stacked together and held by the cylinder studs.

[nasone32]

Thanks Frits, I will send a mail to Your friend later!

TZ350 I have read and answered your message, but i don't have enough posts to send PMs so maybe my reply did not reach your inbox. If this is the case, please send me an email address where I can reply, thanks!

[dinamik2t]

Frits, You have spent a decade thinking of a good&simple 24/7 system and you have probably concluded to something good.
But I liked the "challenge" of thinking a 24/7 system that incorporates a reed petal opening, plus is as free-open as a plain hole when opened!

Could you explain a little more analytical, why a reed valve would be usefull only during start-up? It would give a few hints more.

I thought about it last night in bed. I imagined a butterfly throttle, after the intake rubber (where reed opening is), that would open via a servo motor on specific RPM. On the butterfly half that moves into the case, there would be a reed petal, just like a reed valve.
It sounds simple and can be tuned in regards to RPM and TPS perhaps.
One problem will be petal stiffness I think, as the small petal length would need a thin reed. And at full closed or when at 90* angle (vertical), the petal would break. If support is used behind it, that would get into the mixture's way when fully open.
Things might be better for the petals if the butterfly has a full closed zero-point at 60* from horizontal.
Care to give me a comment?:innocent:

[F5 Dave]

Y. . .
Which complicated reedblock are you talking about? The one with the two hinged reeds coupled by gears that you may have seen in www.pit-lane.biz (http://www.pit-lane.biz)?
That was the very first prototype, over ten years old now. It was over-engineered all right; just one hinged reed without any gears will do just fine.....
Yes that was the picture in my mind I saw on some other website ages ago & then on Pit-lane so it stuck, though I knew there was a simpler one, but couldn't picture it (with or without a Monster next to it). Thanks for the reply.

[TerraRoot]

how a bout two fingers that slide into the reed cage and hold the petals open, obviously won't work on vforce reeds and more petals = more fingers.
could simply have the fingers attached by cable to the powervalve, no extra servo, 24/7 during the powerband.

[Frits Overmars]

how about two fingers that slide into the reed cage and hold the petals open, obviously won't work on vforce reeds and more petals = more fingers.
could simply have the fingers attached by cable to the powervalve, no extra servo, 24/7 during the powerband.That's the general idea, TerraRoot; the 24/7-valve and the exhaust powervalve can be synchronized.
But you do not need a fancy reed cage. As long as the engine is running below the powerband, it is not making power anyway, so the reed does not have to be sophisticated; a simple single reed petal will suffice. Remember, it is there only to start the engine. And instead of a finger to hold the reed open, you can mount the reed on a shaft; that makes swinging it out of the way much easier.
Here is that original picture once more for those of you who haven't seen it yet: over-engineered like I said. One shaft with one petal (and of course no gears) will suffice.

[TerraRoot]

ah trapped myself there, forgot that it is simpler to do a new design rather then add to an existing design. that what i get for snapping off ideas :facepalm:

this 24/7 idea could prove useful to runner 180's, they have tiny cages meant for a 50cc.

[TZ350]

Av's race report from the Nationals .....

254921

[TZ350]

254941

Made an adjustable PJ out of a model aero engine carb needle jet for controlling the PJ. Now to get one of those solenoids the Husaburg posted to shut off the PJ for a bit of extra over rev.

Made some progress with the shorter inlet tract and expect to get the lower mid range back again with a bit of fiddling with the carburation.

Just a little bit more and the single exhaust port engine with the RS pipe will be very close to EngMod2T's predicted power output.

254940 125cc rotary valve with a 24mm carb and air cooled.

Measured 31 rwhp (estimated 34 crank hp) on the dyno tonight, red line is last night before the inlet tract was shortened and the jetting/ignition adjusted.

I have ordered one of Wobblys special kitset "A" Kit Pipes for a Suzuki GP125 ..... so hopefully 1 or 2 more hp and a wider spread of power. Then there is the ATAC idea for better low end.

[koba]

I've had my bike on the dyno.

I got quite a surprise.

http://www.youtube.com/watch?v=54m2CD47BUs

[F5 Dave]

I've only seen bits of that movie, must do so complete some day.

& yes I can confirm Koba's story.

[quallman1234]

I've had my bike on the dyno.

I got quite a surprise.

http://www.youtube.com/watch?v=54m2CD47BUs

Spill the beans yo.

[F5 Dave]

He did.:confused:

[TZ350]

Page 410 collection of interesting stuff from the last 10 pages, there are other interesting collections on each decade page, helps making finding the good tec stuff easier.


I also found this with the dimensions of a lot of inlet manifolds etc
http://www.allensperformance.co.uk/products-manifolds.html


Inlet manifold data Gold.


EngMod2T

Grumph sent me some ideas about fitting a resonator after the carb, with his permision I have posted them.

"If I was you I'd try a proper heimoltz resonator....About 2 X cylinder volume and with a 24mm inlet.

with the big open end you're not getting the best from it.

the original use for them was F3 car motors - 1300cc if I have it right - but they were restricted to a 30mm ID inlet - the FIA wanted a 30mm carb obviously. What the builders did was short inlets into a log manifold - the resonator - with a 30mm inlet trumpet stuck on one end. With port injection they got better power than individual runner injection.

NASCAR V8's have used this setup with the restrictor carbs - one resonator per bank. Grumph"


You have to be careful when using the sim as a predictor of actual power.
You see even using the scavenging model of a RS125 isnt strictly accurate, as the GP has a huge A port and small B,C.
The axial up angles may be the same but I doubt the scavenging and or trapping efficiency are equal.
If you reduce the combustion efficiency a few % then you will get alot closer to reality.

The other issue is that to do what you are trying to do properly, you seriously need to plot egt against rpm on the dyno..
If you get such a huge difference in power by changing the main, then it was well wrong in the first place.
And yes, an electronic powerjet will add at leat 800 rpm of free power to that graph, if switched correctly with the right jet ratios - blowing Speedpro of the planet, unless of course he does what I told him.


I have become very interested in how to use a rolling road dyno properly and the inherant errors in inertia dynos used for measuring RWHP.

Food for thought on dyno errors and dyno technique.

http://www.sdsefi.com/techdyno.htm
http://www.stahlheaders.com/Lit_Dyno info.htm
http://www.modified.com/editors/technobabble/9907scc_technobabble/index.html
http://www.pumaracing.co.uk/POWER3.htm
http://www.pumaracing.co.uk/coastdwn.htm



Re the dyno vs crank conversion.Many people have done this check on many setups, and the general consensus is that when using an inertia dyno on the sprocket
the difference is around 5 - 8% , and when using the rear wheel the difference is 12 to 16%.
These are the losses in the transmission/chain/tyre etc and seem to very similar % wise for a 125GP or a 1000 Superbike.
The BSL made 55 Hp per cylinder on the single with a crank driven dyno, at the same stage the triple in the bike read 142 at the rear wheel on a Dynojet - you do the math.

Really who gives a shit about the actual raw numbers generated, as long as the power curve shape and peak rpm point coincide between reality and the sim,then both the dyno and the sim can highlight if a change is better or worse.
The sims nowdays are a very good prediction tool, and way quicker/cheaper than the time spent cutting/shutting and dynoing for hours - unless of course you are being paid to do it..






Chassis dynos are great tuning aids but they only give a approximation of power output as some of the important variables are not accurately controlled. Tire pressure and wheel alignment can have very significant effects on losses at the rollers. Tire pressures should be set the same between each test.


Nothing is stopping you...


another factor not taken into account or different inertial weight of different tyres and wheels, after all its an inertia dyno and changing the overall inertial weight that has to be spun up changes the HP reading.

Which makes an inertial dyno the perfect instrument for the development of competition engines. Because that is reality: a bike with lighter wheels will accelerate a bit faster.
Use a gearing on the dyno that gives you an acceleration time, equal to the time between gear shifts at the track. Then you will measure the engine the way it has to perform in real life. And the biggest advantage will be that the exhaust pipe will then heat up and cool down on the dyno just like it does on the track.

a lot has been said about measuring the losses between dyno and crankshaft. Forget about that; it's bullshit.

Losses caused by friction between gears are load-dependent. You cannot establish those by way of a coast-down measurement, because once the engine power is gone, the load is gone (or at least decimated).


The old chestnut about heavy wheels and even worse the shitbox Harleys that have heavy flywheels "causing them "to make less power than a wee kart engine
on the rollers is a huge crock of shit.
The reality of the situation seems to escape some very clever people, alot of whom post on the net and sell dyno's as well - funny that.
At the end of the day the reason we put the kart - engine, bike, jetski, on the dyno is to achieve a "better " state of tune.
Once that is done, then taking the FZR and fitting light wheels will make it produce more "power " and it will be faster on the track because of this.
Changing from cast iron wheels, to carbon composite wheels is a "tuning" aid , just as much as a Wobbly pipe might be.
The rolling road will show this - the engine dyno wont.
Again as I keep saying - who gives a shit - if it makes more power on any dyno, no matter what the number is, it will be faster.


What I would do: assume a 5 % power loss for every set of gears, for the chain, and for the deformation of the tire on the drum.So what you would measure, is 0.95 (primary drive) * 0.95 (gearbox) * 0.95 (chain) * 0.95 (tire) * crankshaft HP = 0.8145 * crankshaft HP. Or, the other way around: crankshaft HP = drum HP / 0.8145.
Granted, this is not exact, but it's an honest approximation. In any case it is way better than calculating with coast-down losses that you know are not representative of the real losses.
hopefully you noted I spoke of drum HP. That is not the same as rear wheel HP. About 5% of rear wheel HP is lost between tire and drum and what really accelerates the drum, is drum HP. And something which you may not know: Dynojet-readings are already compensated for this loss, and then some. We once did a comparative test at Ten Kate's (umpteen times Supersport world champion, just around the corner from my house). It turned out that the Dynojet is 11% optimistic.


Thanks Frits I had been reading about them the other day on Burgerman he is a bit scathing of them as well.
http://www.dynamometer-info.co.uk/power-losses-flywheel-BHP.htm
Plus another i was on today said just what you said. I note the Bosche Inertia Dynos has two drums and the main drum is twice the weight of the dyno jet.


… here is some mathematical Prozac for you: drum HP = Dynojet HP / 1.11 and crankshaft HP = drum HP / 0.8145. So crankshaft HP = 1.106 * Dynojet HP. And don't bother about those decimals; after all it is an approximation. So it would be safe to say that crankshaft HP = 1.1 * Dynojet HP.

Sleeving cylinders for F4 100 water cooled class.


The site is interesting in which the repairs are carried out i was wondering why i couldn't strip then tig up the whole cylinder and then machine it and re-coat it rather than a sleeve anyway.

Re coating i am not suggesting to send stuff oversea when we have a place in NZ.
Plus yes it would be easier to sleeve a cylinder.

http://www.poetonaptec.co.uk/default.htm
http://www.gkn.com/Pages/default.aspx


Pressing in a sleeve is a no-no to begin with. Shrinking it in is better, but not good enough. Because no matter how tight you make that interference fit, during use oil will creep between cylinder and liner, starting at the exhaust port.
If you remove an old liner, you can see the charred remains of that oil all around the exhaust zone. So do not worry about the limited thermal conductivity of an iron liner; charred oil conducts heat infinitely worse.
Been there, done that. If there's anything that makes me experienced in the two-stroke field, it's the fact that I have personally committed every imaginable error. Racing an air-cooled 500 cc two-stroke single with a liner made me the fastest man in Holland - in drawing a clutch. Not even Lucky Luke could draw quicker .


The ignition timing does not have to be changed when you use an electronic power jet. But both the ignition timing and the powerjet timing are means of influencing the exhaust gas temperature. A late ignition and/or a lean mixture both cause a higher EGT, so you can match the exhaust resonance frequency to a rising engine rpm.
And if you have that power jet available, the ignition does not have to do it all by itself anymore, so you can search for a timing that gives a better overall result.


To give you an idea of the main jet / power jet ratio: typical RSA-values are main 220, power 120. That means the flow area of the power jet is about (120/220)^2 = 0.3 times the flow area of the main jet. And don't shut the power jet until well past the rpm of maximum power or you will risk a maximum seizure.



The Fiat Uno unit was not a solenoid; it was a stepper motor; a rotating device. And stepper motors only function when pulsed.
It's like this I imagine..
Lots can be found under the name 'idle control valve' (not necessarily fiat).

… I found the YZ/KX250 Keihin 38 carb, which is about 1cm shorter than conventional PWK, has a TPS sensor and an electronic PJ! Actually, this carb is more similar to their PWM design, I don't know why they named it PWK. Perhaps "k" brand is more established in the community... It's powerjet solenoid says "Shindengen".




all these talks of solenoids and power jets perhaps a simple EFI system would be better?

http://www.mbe-motorsports.com/catalog/product_info.php/cPath/22/products_id/337

http://www.ecotrons.com/2_Stroke_Small_Engine_EFI_kit.html

http://www.ecotrons.com/website/2T_EFI_Kit_mid.jpgThere is a current discussion on ekartingnews about EFI 2T http://ekartingnews.com/viewtopic.php?t=110370&postdays=0&postorder=asc&start=75
They have a pic of a CR500. Some guys are creating their own using known fuel distribution curve and neediel/tube graphs as a guide for fuel flow.

thats a great thread, loving some of the info the HGT guys give out.

here another one with the ecotrons:
http://www.scootforum.com/viewtopic.php?f=95&t=710&st=0&sk=t&sd=a&sid=fb2f8400a0719cb17aa6cba9c463c4a0
and another with MS:
http://www.125ccsportsbikes.com/forums/index.php?showtopic=63480&st=0

This is a big post on control circuits and worth a look.


Its a big one sorry all this talk of piggy back circuits.
These curcuits can also be used in numerous ways partically like a couple of them.
use a microcontroller to generate the required PWM signals, the 555 PWM circuit explained here will give the novice robot builder an easy to construct circuit, and good understanding of pulse width modulation. It is also useful in a variety of other applications where the PWM setting need only be changed occasionally.

The 555 timer in the PWM circuit is configured as an astable oscillator. This means that once power is applied, the 555 will oscillate without any external trigger. Before the technical explanation of the circuit, let's look at the 555 timer IC itself. http://www.dprg.org/tutorials/2005-11a/index.html


Right i had a wee search on the net.
The genuine kit is a little expensive, I couldn't find the Keihin but here is the Mikuni, as you know i had already posted this.$303nz.
Maybe the Keihin kit is less expensive.

I haven't had the chance to look through Sudco yet.
Had a wee look at Sudco it seems the soilniod is not listed as a separate part bugger.

Here is one from the UK Mikuni person no prices.
http://www.allensperformance.co.uk/products-power jet kits.html

I also found this with the dimensions of a lot of inlet manifolds etc
http://www.allensperformance.co.uk/products-manifolds.html

TZ's keihin copy carbs i believe have a Powerjet the obvious way to me for a budget conscious bucket racer would be to modify this for electric use with a car solenoid.


PWM control of the powerjet is a very sexy use of technology,slowly ramping off the fuel flow against rpm, but in reality using a simple rpm controlled switched solenoid work perfectly fine.
Yamaha and Honda have used the switched powerjet since forever, its reliable and does the job.
Only issue you need to address is the jet size and switch point ( along with TPS value ).
Running Avgas as we are still allowed to do, means that the tuning is based around getting high egt numbers to create good power, with lots of com and advance - unleaded is the opposite..
Thus experience has shown that as leaded fuel works best with a lean condition at peak power, we only need to switch a small jet just past peak - to increase the pipe temp and
thus give better overev.
In the Keihin numbering this is in mm dia and switching off a .35 is perfect.
When running unleaded, as the GP bikes have for years, the fuel likes to be rich at peak to create the best power, thus we need to switch off alot of fuel flow to increase the pipe heat quickly enough.
In this case a .65 is needed to do the job.
On the dyno or on the track it is easy to tell if the switch point is a little too low, as it feels exactly like the bike has changed into another gear past 6th.
It jumps forward when the solenoid kicks in - making the fuel curve lean, too early.Do this enough - and bang.
Its critical to 100rpm, and is working perfectly when you dont feel it happen - the power just keeps going.
To do it on the dyno you have to run the bike in 6th to simulate the acceleration rate as seen in that gear on the track, and is easy to do running back to back run ups.
Changing the rpm number 100 at a time, lower in the Ignitech, reprogram on the fly and run again.
If the rpm is too high - nothing happens, as there isnt time for the heat to affect the pipe wave speed.


thats a great thread, loving some of the info the HGT guys give out.

here another one with the ecotrons:
http://www.scootforum.com/viewtopic.php?f=95&t=710&st=0&sk=t&sd=a&sid=fb2f8400a0719cb17aa6cba9c463c4a0
and another with MS:
http://www.125ccsportsbikes.com/forums/index.php?showtopic=63480&st=0


It just occurred to me TeeZee that you guys need to feed a free copy of Gadwin printscreen into the dyno computer.
You can save to a file or a printer very easy.


That's the general idea, TerraRoot; the 24/7-valve and the exhaust powervalve can be synchronized.

254976

But you do not need a fancy reed cage. As long as the engine is running below the powerband, it is not making power anyway, so the reed does not have to be sophisticated; a simple single reed petal will suffice. Remember, it is there only to start the engine. And instead of a finger to hold the reed open, you can mount the reed on a shaft; that makes swinging it out of the way much easier.
Here is that original picture once more for those of you who haven't seen it yet: over-engineered like I said. One shaft with one petal (and of course no gears) will suffice.

[TZ350]

There is something going on with my carb that I don't understand.

I can see the fuel drawn up the line to the PJ as the rev's build up, and this is what I would expect to see. Then when the rev's are getting to around 10-12K the fuel drops back, something I didn't expect to see. I have seen this on other carbs and it can't be a good thing.

This means that at higher rpm the pressure in the float bowl is less than inside the carb's bell mouth.

How can this happen?

[dinamik2t]

Perhaps pressure/drain through main jet is so high that no fuel makes it up the fuel line of the PJ. A loose fitting-air leak that lowers PJ's feed circuit pressure would probalby enhance this phenomenom - I think.

[teriks]

There is something going on with my carb that I don't understand.

I can see the fuel drawn up the line to the PJ as the rev's build up, and this is what I would expect to see. Then when the rev's are getting to around 10-12K the fuel drops back, something I didn't expect to see. I have seen this on other carbs and it can't be a good thing.

This means that at higher rpm the pressure in the float bowl is less than inside the carb's bell mouth.

How can this happen?
Well, that just tells me that the pressure in the float bowl is less that the pressure at the _PJ-entry_ into the carb.
Now, the pressure at the main jet entry must be less than that of the float bowl, otherwise the engine would die, right?

-Perhaps this is an effect of the PJ-entrys position in the shortened bellmouth? Could you show this (bellmout and pj-entry) somehow?

[F5 Dave]

Anyway; All hail the new HP arms race leader.:apumpin: Good work TZ

[dinamik2t]

Actually, low pressure is what draws air -and so fuel- from a higher pressure area. Both main and powerjet draw fuel from the same bowl. And that fuel is drown by the same sub-atmospheric pressure of the crankcases. Powerjet's fuel though has to rise up the line, in comparisson to the main jet which is just above the fuel bowl.
So, in theory, at PJ needle opening in the venturi, a larder sub pressure would be needed to accomodate for the extra travel of the fuel.

Since back-flow happens, I guess that either too large fuel amount is drawn and it chooses the shorter way or PJ circuit is bleeding somewhere causing pressure to rise near-er to the higher atmospheric, thus fuel is drawn back.

I 'm thinking of a logical solution and I will edit -unless somebody already knows how to fix it.

[F5 Dave]

I have no idea what you are seeing physically, but could it be there is inertia forcing too much fuel up & causing reflections of some of the gas back down the sides to make room as more is pumped up the middle of the tube, you see the outer flow returning perhaps?

[bucketracer]

TeeZee has asked me to help make a video of it, will see if we can do this tonight.

[jasonu]

I've had my bike on the dyno.

I got quite a surprise.

http://www.youtube.com/watch?v=54m2CD47BUs

What's wrong with it?

[koba]

What's wrong with it?

No obvious faults as such, it's in a real low state of tune.

The broad nature of the power delivery... Oh no, It doesn't have that either! It's only over a 1000rpm range and drops of greatly either side with a small spike much later on.

I suspect the porting is insufficient to allow it to get on the pipe. Furthermore, the Crank-case compression has been lowered significantly by the way I mounted the carb. There was a reason for me doing it this way but it probably won't manifest until I'm pushing the engine a lot more.

I have got plans and I suspect to see a good boost when I finally get the barrel raised and the exhaust port hogged out bigger than a prison bitches bumhole.

[F5 Dave]

don't forget the compression raised but std ign & no adjustment made.

But the plus side is it did make its stella performance at about 8000 rpm.:niceone:

[koba]

don't forget the compression raised but std ign & no adjustment made.

But the plus side is it did make its stella performance at about 8000 rpm.:niceone:

That too! Haha.

On the positive side I now know I'm not full of shit and making excuses when I say my bike is gutless.

[TZ350]

There is something going on with my carb that I don't understand.

I can see the fuel drawn up the line to the PJ as the rev's build up, and this is what I would expect to see. Then when the rev's are getting to around 10-12K the fuel drops back, something I didn't expect to see. I have seen this on other carbs and it can't be a good thing.

This means that at higher rpm the pressure in the float bowl is less than inside the carb's bell mouth.

How can this happen?


TeeZee has asked me to help make a video of it, will see if we can do this tonight.

Someone thought if I was looking for more horses they would help!!!! cheaky sods ...... :laugh:

254969
Well we got all sorted to video this PJ problem and :Oops: it had disapeared ... :o ...

254970

The OKO main jet and lower half of the venturie is a removable piece and earlier in the day I had glued up all around the joint on my one to seal it.

It must have had an air leak because the problem has gone and we now get consistant runs on the dyno.

I have seen this PJ problem on other OKO carbs so its possibly something to look out for on any Keihin copy carb.

Its all good to go now ... :D

[Buckets4Me]

Someone thought if I was looking for more horses they would help!!!!

254969


that isn't a help it's a ZEBRA 254980 it is riding an early E.S.E engined gp125

[teriks]

Well we got all sorted to video this PJ problem and :Oops: it had disapeared ... :o .
Not the pj-entry location then.
I was under the impression that you had modified the carb bell to shorten the inlet tract, seems I got that wrong also.

[TZ350]

Every idea was a good idea as it realy had me stumped and I needed all the help I could get, it was more by luck than good management that the glue sorted it out, but logical when you think about it.

[dinamik2t]

Glad you sorted it out TZ :)
Actually, PWKs have this seperate 'base' (obviously, since Oko copies them) and there is a band and an o-ring to seal the part.
Oko was just glued, eh?

By the way, your dyno result is impressive with a single ex! Congrats!:Punk:

[Frits Overmars]

Actually, low pressure is what draws air -and so fuel- from a higher pressure area. Both main and powerjet draw fuel from the same bowl. And that fuel is drown by the same sub-atmospheric pressure of the crankcases.Nope. It is drawn by the dynamic pressure at the fuel exit points in the carburetter. And that pressure depends on the mean air flow velocity along those exits.
Air flow velocity is at its highest in the center of the narrowest part of the inlet tract, so the location of the fuel exit will make a difference. And by mean air flow I mean (air flow into the engine + backflow)/2.
You see, more than enough variables; more than enough differences between the exit points of the fuel flow through the main jet and the flow through the power jet.

[2T Institute]

What's everyones thoughts on the tiny atomising bleed hole on the front side of Mikuni TZ power jet discharge tube?

[wobbly]

Re the tiny bleed hole in the TZ powerjet tube - I always thought that this was a good idea to emulsify the fuel as it exited the dropper.
But years ago i did some wet tests on the flowbench with a VCR video camera ( pretty trick shit stuff back then ).
The Mikuni was a horror scene when played back slo mo,with huge "gobbs" of fuel exiting the main and powerjet.
We then stuck on a Lectron - wow, lovely fine mist of fuel from the back of the flat needle face - and it flowed 12% more air - size for size with a venturi 2mm smaller behind the slide.

Next is the current state of TeeZees GP125, here is the latest dyno curve digitised with 16% added to simulate crank power.
Then there is the sim with an actual RS early model pipe.
Then there is the new pipe of my design.
Of most interest is that in this case the sim is giving slightly too much crank power - but the shape and peak point are all but perfect.
I would be confident now that any change in the sim, would be reflected in reality on the dyno.
In my experience the later Dynojets like a twin roller 168 with Eddy current load control to slow the acceleration rate down ,seem to read around 5 to 10% lower
so this would put the sim and the dyno reading very close, as the shape is spot on now.

[dinamik2t]

Nope. It is drawn by the dynamic pressure at the fuel exit points in the carburetter. And that pressure depends on the mean air flow velocity along those exits.
Air flow velocity is at its highest in the center of the narrowest part of the inlet tract, so the location of the fuel exit will make a difference. And by mean air flow I mean (air flow into the engine + backflow)/2.
You see, more than enough variables; more than enough differences between the exit points of the fuel flow through the main jet and the flow through the power jet.

Aha, I see. I think I got it now, Frits.
If the powerjet is positioned in the middle of the venturi or at a lower point, that will affect how much it will flow, correct?

I remember both Lectron and Mikuni aftermarket PJ kits' instructions, saying that the end tip of the pj should be around the middle of the carb.
Yet the Keihin PJ of the carbs for the mx250 models is down low! Position would also affect which fraction of the flow becomes more rich or not, or that doesn't matter??

255006

[wobbly]

When using a simple powerjet nozzle the tip position matters in that no flow will occur until the slide is well past the exit hole, and there is sufficient airflow
to drag fuel up the feed tube above the bowl level.
With the aftermarket add ons and the ones as used by Lectron you can shorten the dump tube so that the flow will only occur at high slide openings,as well as high air flow.
These also have a built in "lag "control in that it takes time for the fuel to rise up the tube and dump out the exit into the air stream.
With a solenoid controlled setup all this is pretty much irrelevant as the flow can only occur when the solenoid is not powered up, and this
is TPS as well as rpm dependant inside the ECU program..
The carbs as used on the MX bikes has the dump tube very low in the bore as they added and subtracted fuel at low slide positions in those bikes.
For a race engine I bend the tube up to around 1/2 bore, as this is where the exit is on the Kehin SPJ carb for RS125/RS250 Honda.
And the general setting is the solenoid is powered up ie no flow below 4000 and 60% TPS and is powered up again at around 12400 to lean off the mixture and increase revon.
This causes a problem with Ignitechs that are used with only a capacitor, as at startup the solenoid is powered up, dragging all the voltage out of the ECU, so I convert the ECU output
to a 3 step truth table, and have the setting such that below 1500rpm the solenoid isnt powered.

[dinamik2t]

You mean something like this, eh?
255013

As for the bending.. I rememder heating copper pipes in hydraulics and filling them with sand to bend them. I assume same would be applicable to brass, which is similar to copper, but would it be a good idea to fill the PJ's tube with sand?? :no:
I 'll check tomorrow and see whether the tubing can be removed from the carb body, to bend it with an actual tube bender.

Thanks for the explanations Wob!

[wobbly]

The tube is thick walled and bends easily by simply levering it up.
You can take it out, but then when its bent it wont go back in,as its designed to be pushed in from the outside.
Here is the table

[TZ350]

""Hi Tz350, I want to ask your help to test some expansion chamber design software...
So I got this software like the one mentioned on :
http://www.kiwibiker.co.nz/forums/sh...15#post1779915 (http://www.kiwibiker.co.nz/forums/showthread.php/84336-Timing-GP125?p=1779915#post1779915)

I want to test the result on my engine spec but can't afford to build one this time..
So I've input your spec as in http://www.kiwibiker.co.nz/forums/sh...post1130226187 (http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130226187#post1130226187) on this software, if you have any spare time, can you test it on your engmod2t?

1st one : I input with same bmep (about 37.2 @ 12500)

255041

2nd : I input with higher bmep but lower rpm (about 37 @11500)

255042

I guess engmod2t result could give an idea about what can we expect from this software..
thx in advance tz350.. ""

There you go ..... I hope the results encourage you to get a copy of the pipe software and your own copy of EngMod2T to continue the development of your GP125.

EngMod2T is not that expensive and as you can see, worth every penny as an evaluation tool. It can also warn you of potentialy dangerous thermal conditions if you look at some of the other graphs that it can display related to the combustion process.

[pugs]

There you go ..... I hope the results encourage you to get a copy of the pipe software and your own copy of EngMod2T to continue the development of your GP125.
EngMod2T is not that expensive and as you can see, worth every penny as an evaluation tool.

Wow, thank you so much Tz.., turn out this software worked pretty well..
Actually I already have this software, but it's just me that still confused, which one I will choose for my next pipe: this software or Frits's design.. (And now it made me confused even more.. x_x)

Another question, if you don't mind, will you share, what number (peak rpm & sound speed) that you inputed for Frits's design so it can achieve 43@13250? It's okay if you want to keep it for ese's team..
Oh.., surely Engmod2t will be the first on my wish list..:)

Question for Frits..
(sorry I hijack your thread tz.., but now, i just can't help myself..)
Frits, when I put bigger engine capacity (150cc) on your pipe formula, while other parameter stay still, dx number are getting much bigger.. (& since approx. power output doesn't included in dx equation, lower hp number would not change that...)

I always thought that same port area (engine breathing-capacity) will generate same achievable-power on the similar rpm.. Well, maybe less on the bigger capacity due to more reciprocating mass. Um..., is that the reason? I mean, is reciprocating-mass affecting rpm that much? (125cc @12000rpm dx = 150cc@10000rpm dx)
Or there's another explanation? Thank you for the enlightenment...

[TZ350]

Thanks, Mental; everything seems to be fine now. So here they are again:

http://www.kiwibiker.co.nz/manual/Aprilia-1.zip (http://www.kiwibiker.co.nz/manual/Aprilia-1.zip) (6.8 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-2.zip (http://www.kiwibiker.co.nz/manual/Aprilia-2.zip) (8.3 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-3.zip (http://www.kiwibiker.co.nz/manual/Aprilia-3.zip) (9.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-4.zip (http://www.kiwibiker.co.nz/manual/Aprilia-4.zip) (7.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-5.zip (http://www.kiwibiker.co.nz/manual/Aprilia-5.zip) (5.6 MB)

The pipe design I used in that simulation was the simpler one I found of Frits's on the Aprilia-3.zip file. I don't know the rpm and sound speed he used but the simulator liked it and it does look fairly easy to make.


Another question, if you don't mind, will you share, what number (peak rpm & sound speed) that you inputed for Frits's design so it can achieve 43@13250? It's okay if you want to keep it for ese's team...

There are no secrets at Team ESE, we post everything we do, its the fun of making friends, sharing ideas, riding bikes and building stuff we enjoy.

[speedpro]

There are no secrets at Team ESE, we post everything we do, its the fun of making friends and building stuff we enjoy.

I'm actually on my way there this morning to measure up a few things

[wobbly]

Just a couple of points re the pipe designs shown above.
The header length at 37% is just plain dumb and very wrong, never seen a pipe on any engine that worked with that %.It should be in the 31 to 33 range.
And running a 19mm stinger on any 125 that makes any power at all - IT WILL BLOW UP.
Also its very short sighted to take Frits pipe layout from a 125 GP rotary valve engine that makes over 50 Hp around 13000, and simply bung it onto an air cooled bucket engine
with a 24mm carb that needs a huge level of input to make 30 RWHp.
Aprilia made arm loads of test pipes to understand what worked on that engine,and for sure it wont work well on the GP125 bucket - its the design intent that is important, not the actual numbers.

[TZ350]

The header length at 37% is just plain dumb and very wrong, never seen a pipe on any engine that worked with that %.It should be in the 31 to 33 range... - its the design intent that is important.

I would like to know more about these percentages, and how they relate to pipe design philosophy in general.

[Ocean1]

- its the design intent that is important, not the actual numbers.

I'm hugely relieved to hear you say that, the numbers some of my designs produce come nowhere near what I intended.

[dmcca]

The carbs as used on the MX bikes has the dump tube very low in the bore as they added and subtracted fuel at low slide positions in those bikes.
For a race engine I bend the tube up to around 1/2 bore, as this is where the exit is on the Kehin SPJ carb for RS125/RS250 Honda.
And the general setting is the solenoid is powered up ie no flow below 4000 and 60% TPS and is powered up again at around 12400 to lean off the mixture and increase revon.
This causes a problem with Ignitechs that are used with only a capacitor, as at startup the solenoid is powered up, dragging all the voltage out of the ECU, so I convert the ECU output
to a 3 step truth table, and have the setting such that below 1500rpm the solenoid isnt powered.

ah this might explain why I am still having such big startup issues with the ignitech... Now running a battery to make starts easy.

Wobbly do you know what the powerjet settings look like on a stock yz250 in terms of on/off rpm and tps?

[Frits Overmars]

....I always thought that same port area (engine breathing-capacity) will generate same achievable-power on the similar rpm.. Well, maybe less on the bigger capacity due to more reciprocating mass. Um..., is that the reason? I mean, is reciprocating-mass affecting rpm that much? (125cc @12000rpm dx = 150cc@10000rpm dx)Not quite, Pugs. Engine breathing capacity is not expressed in port area but in angle.area. For example you can have a transfer port, 1 cm wide and 1 cm high, so it has an area of 1 cm². If that same port is situated 1 cm higher in the cylinder, it will still have the same area, but it will have a much longer open timing, so there is more time available for flow through that port.
Identical angle.areas will give identical achievable power, but that need not happen at identical rpm. If an engine has twice the cubic capacity it will take twice the time to scavenge it through a given angle.area. That means it has to rev twice as slowly, or it will not be completely scavenged.
The ratio (angle.area divided by cubic capacity) is called specific angle.area. And specific angle.area divided by rpm is called specific time.area.
To summarize: specific time.area is port area, multiplied by the time during which it is open, per cc.
Reciprocating mass limits the maximum safe rpm that the crankshaft will tolerate. Specific time.area limits the maximum rpm at which the cylinder can still be completely scavenged.

[wobbly]

If I were to explain pipe design I would need to write a book,but in general things are pretty straight forward in relation to the % values.
End of header is always 31 to 33% and end of diffuser is always 62 to 68%.
To see the effect of a silly long header, you can watch the pressure ratio at the Ex port, and thus the effect this has on the depression in the cylinder.
We are looking for the lowest and widest negative ratio we can get around bdc when the transfers are fully open.
A long header delays the beginning of the depression too late in the cycle, when in the power band.
In a race 2T we are always fighting power range Vs peak power.
Shorter diffusers create steeper angles,thus greater wave amplitude, but this narrows the effective band width.
So - in general the best compromise is around 66%.

[cookie1965]

Gentlemen, I'd just like to poke my nose in here and say that I've been lurking in this thread for quite some time and it just keeps getting better and better. By far the most informative thread I've found on 2 stroke design. Thanks to all and keep at it. As a guy who plays with 2 strokes as a (very expensive) hobby, I really appreciate everything openly posted here. The fellow who rides the race RZs I build thanks you too.

[dmcca]

If I were to explain pipe design I would need to write a book

i'd pay a premium for that... seriously. But I know the economics of it aren't good.

[Frits Overmars]

...As a guy who plays with 2 strokes as a (very expensive) hobby, I really appreciate everything openly posted here.A well-played violin can be poignant. Do you know what is even more poignant? two violins.
It's the same with engines. Playing with 2 strokes can be an expensive hobby. Can you guess what is even more expensive? :msn-wink:

[cookie1965]

oops, double posted

[cookie1965]

LOL. Fair enough Frits, thats some perspective. Expensive is relative of course. In the last couple of months I've bought a TD2 project bike, a TZR250 for one of my projects and more parts and services bike related than my marriage could stand were it openly discussed.
In the spirit of the co-operation already in this thread, and considering that fuel injection was brought up earlier, here is the beginning of a prototype system I've been playing with. I'd appreciate any feedback, hopefully productive. If you'd like to say it won't work that's fine but please explain why?

http://i48.photobucket.com/albums/f224/cookie1965/pfi2.jpg

http://i48.photobucket.com/albums/f224/cookie1965/pfi4.jpg

Now some of you may recognize my name as a member of another forum where FI has been discussed,(I recognize some of your usernames), and may hold against me some things I said there. Please understand that my comments there were made because of my frustration with a poster there and his apparent arrogance and unwillingness to share information. Don't misunderstand me, I don't believe that it was required of him, but rather than refuse to answer questions he acted as though the questions were somehow beneath him. I would appreciate it if these pics didn't appear elsewhere. I'd rather it be running before I face the firestorm. Thanks.

edit. I really don't know why those pics are so small...sorry

[TZ350]

Playing with 2 strokes can be an expensive hobby. Can you guess what is even more expensive? :msn-wink:

255068

My bet is ...... BikerChick

[speedpro]

255068

My bet is ......

2 strokes and good looking women . . . I'm willing to pay the cost.

Re the FI above, the idea looks good but I have serious reservations about the manifold. I would have thought a nice tuned length velocity stack arrangement for each cylinder into an airbox with the injector mounted overhead would flow better. TZ has shared quite a bit of info about what has improved the flow through his carbs. I'd be tempted to even go for some sort of nozzle/venturi leading to the reed cages to create a high velocity section. It could be a good tuning enhancement, you could change it's location and dimensions depending on results. It could even be made variable easily. I'm sure you have already done it but there is good gains to be had by filling in the reed cages and keeping the cross-sectional area constant or tapering slightly to the reeds. What management system are you using?

[explode64]

New electronic carb by dellorto http://www.dellorto.it/ecs.asp you may need to change it to english

[TZ350]

If Wiseco is your thing ....

New Zealand supplier in Auckland of Wiseco rings, sleeves and piston kits.

http://www.sportspro.co.nz/products/1150-engine/1036-wiseco_rings.aspx

[dinamik2t]

Wob, those percentages are refering to the tuned length of the pipe? Transition nozzles/flanges at the beginning should be taken into account? - you refered to end of parts, that's why I'm asking.:scratch:

[speedpro]

If Wiseco is your thing ....

New Zealand supplier in Auckland of Wiseco rings, sleeves and piston kits.

http://www.sportspro.co.nz/products/1150-engine/1036-wiseco_rings.aspx

I see they have 95mm sets so Richban will be interested.

[husaberg]

Playing with 2 strokes can be an expensive hobby. Can you guess what is even more expensive? :msn-wink:
I guess one may feel like it has cost and arm and a leg.
One could cost your arms or your legs.
While the other is likely to eventually cost you your life.

2 strokes are twice the fun and a lot less expensive, than the middle ones.
Everyone knows anything more than 2 strokes is Masturbation. Source coxford dictionary


I see they have 95mm sets so Richban will be interested.

Re Richban's 95mm+ piston
You guys, it is not cheating!
The fact is its all legit.

It added up just fine on the calculator.
Its just he's a bit errr...dyslexic.
In fact according to his new calculations, he could stroke it as well now, and it will still be under 551cc:innocent:

[pugs]

There are no secrets at Team ESE, we post everything we do, its the fun of making friends, sharing ideas, riding bikes and building stuff we enjoy.My respect for you and the rest of ese's team, sir..


The header length at 37% is just plain dumb and very wrong, never seen a pipe on any engine that worked with that %.It should be in the 31 to 33 range.
And running a 19mm stinger on any 125 that makes any power at all - IT WILL BLOW UP.
...its the design intent that is important, not the actual numbers.Yes, I notice that, especially the stinger diameter that is getting smaller and smaller with higher bmep input, thanks Wob. Well, maybe I would just use this software for less demanding stuff..


To summarize: specific time.area is port area, multiplied by the time during which it is open, per cc.
Thank you for reminding me about that Frits, I knew I was missing something here..


I would like to know more about these percentages, and how they relate to pipe design philosophy in general.
Sorry if this was already posted here, but it help me a lot about pipe design philosophy.. (unfortunately in dutch..)
http://www.ytcn.nl/archief/Archief/expansiepijpen/Expansie_uitlaten.pdf

[richban]

I see they have 95mm sets so Richban will be interested.

Its a bit early for mud slinging Mike.

But I suppose the next GP is not far away. I hope you lot will have finished your spannering buy then.

[TZ350]

Ten characters


i see they have 95mm sets so richban will be interested.

.... :D

[wobbly]

The % I quoted for header means that portion of the length from piston to rear cone end.
Its from the piston to the beginning of the diffuser, what happens in between isnt relevant.
Unless of course you use a small Ex duct and a bigger header, that makes more power.
And of course same for the diffuser end, that is simply 66% of the length from the piston to the end of the rear cone.

[2T Institute]

Just a couple of points re the pipe designs shown above.
The header length at 37% is just plain dumb and very wrong, never seen a pipe on any engine that worked with that %.It should be in the 31 to 33 range.
And running a 19mm stinger on any 125 that makes any power at all - IT WILL BLOW UP.
Also its very short sighted to take Frits pipe layout from a 125 GP rotary valve engine that makes over 50 Hp around 13000, and simply bung it onto an air cooled bucket engine
with a 24mm carb that needs a huge level of input to make 30 RWHp.
Aprilia made arm loads of test pipes to understand what worked on that engine,and for sure it wont work well on the GP125 bucket - its the design intent that is important, not the actual numbers.

Exactly why I say cheap on-line pipe calculators are worth every cent you pay.

[F5 Dave]

LOL. Fair enough Frits, thats some perspective. Expensive is relative of course. In the last couple of months I've bought a TD2 project bike, a TZR250 for one of my projects and more parts and services bike related than my marriage could stand were it openly discussed.
In the spirit of the co-operation already in this thread, and considering that fuel injection was brought up earlier, here is the beginning of a prototype system I've been playing with. I'd appreciate any feedback, hopefully productive. If you'd like to say it won't work that's fine but please explain why?

http://i48.photobucket.com/albums/f224/cookie1965/pfi2.jpg

http://i48.photobucket.com/albums/f224/cookie1965/pfi4.jpg

Now some of you may recognize my name as a member of another forum where FI has been discussed,(I recognize some of your usernames), and may hold against me some things I said there. Please understand that my comments there were made because of my frustration with a poster there and his apparent arrogance and unwillingness to share information. Don't misunderstand me, I don't believe that it was required of him, but rather than refuse to answer questions he acted as though the questions were somehow beneath him. I would appreciate it if these pics didn't appear elsewhere. I'd rather it be running before I face the firestorm. Thanks.

edit. I really don't know why those pics are so small...sorry
Yeah I've kept my nose right out of that. Lets not go there.

[Frits Overmars]

...Sorry if this was already posted here, but it help me a lot about pipe design philosophy.. (unfortunately in dutch..)
http://www.ytcn.nl/archief/Archief/expansiepijpen/Expansie_uitlaten.pdfWhat do you do for a living, Pugs? Archeology? I wrote that stuff 33 years ago! Where did you dig it up?

[dinamik2t]

Also its very short sighted to take Frits pipe layout from a 125 GP rotary valve engine that makes over 50 Hp around 13000, and simply bung it onto an air cooled bucket engine
with a 24mm carb that needs a huge level of input to make 30 RWHp.
Aprilia made arm loads of test pipes to understand what worked on that engine,and for sure it wont work well on the GP125 bucket - its the design intent that is important, not the actual numbers.

Wob, could someone use EngMod to conduct design comparisson tests, according to its engine/application?
What I'm trying to say: in EngMod, are there data to compare pipe designs (or generally modifications) beyond plain numbers, that an inexperienced tuner can interpreter and use?

Would you or Frits be interested to tell us about how you reached this level of knowledge? Did you have someone to help you with the basics, like you help us, or was it more like personal testing and reading and testing? I can imagine you mechanics in the GP teams laboratories, discussing, studying, testing. Younger ones listening, suggesting erroring (if that's a word), elders yawping, helping, teaching.. :)
I know it leaves the topic's boundaries. I think it will be very inspiring though! Perhaps it will remind you good old days too. :D

[cookie1965]

2 strokes and good looking women . . . I'm willing to pay the cost.

Re the FI above, the idea looks good but I have serious reservations about the manifold. I would have thought a nice tuned length velocity stack arrangement for each cylinder into an airbox with the injector mounted overhead would flow better. TZ has shared quite a bit of info about what has improved the flow through his carbs. I'd be tempted to even go for some sort of nozzle/venturi leading to the reed cages to create a high velocity section. It could be a good tuning enhancement, you could change it's location and dimensions depending on results. It could even be made variable easily. I'm sure you have already done it but there is good gains to be had by filling in the reed cages and keeping the cross-sectional area constant or tapering slightly to the reeds. What management system are you using?

Thanks for the reply. My theory, probably misguided, was that with this set up I was providing enough air flow, since the size of my single TB is equivalent to 2 x 32mm carbs, and the fuel being injected directly at the red cage would be an improvement over the fuel being carried through the longer intake tract. I'm Probably looking at things in too simple a manner.

[wobbly]

EngMod can be used at any level of experience.
Only problem that occurs is crap in = crap out, and you can get VERY mislead in trying any variations of say a pipe design if you
don't know how to optimise the other variables to suit a change.
For example you can spend days getting a really good power graph of a pipe for a 125, but if you run all the sims with a 19mm stinger, the design is flawed from
the start, and will never work on a real engine, no matter how good the sim result seems.
You can, simply run the sim and read off the graphs that pipe A is "better "than pipe B.
But then you can start to "read "the pressure traces within any part of the system and begin to learn WHY a change was better or worse.
And you can graph TuMax to see what is happening in the cylinder head with the squish and timing curve you have entered.
This is the beginning of real tuning knowledge.
One thing that used to be a good help was to use TSR to get in the ballpark with initial EngMod entries, and now Neels has started to help out
with a generic pipe design calculator, but the only way to really get an understanding is to watch the problems caused by a 37% header,on the screen, in real time.

[husaberg]

LOL. Fair enough Frits, thats some perspective. Expensive is relative of course. In the last couple of months I've bought a TD2 project bike, a TZR250 for one of my projects and more parts and services bike related than my marriage could stand were it openly discussed.
In the spirit of the co-operation already in this thread, and considering that fuel injection was brought up earlier, here is the beginning of a prototype system I've been playing with. I'd appreciate any feedback, hopefully productive. If you'd like to say it won't work that's fine but please explain why?

http://i48.photobucket.com/albums/f224/cookie1965/pfi2.jpg

http://i48.photobucket.com/albums/f224/cookie1965/pfi4.jpg


Anything well just about anything can be made to work given enough time, money and more importantly determination.

I concept is great but why one throttle body?
What is the outcome you are after drivablity, fuel consumption,Tune-ability, emissions or performance. ?
The main issues i see is that carbs are light and simple and relatively specking. Ie no battery/alternator, fuel pump regulator ECU etc.
I am not knocking you because it is great to actually do it rather than just thing about it or just ruling it out.
What sort of fuel pressure are you envisaging?
I remember the Cagiva system involved huge pressures.
The biggest potential advantages i see with fuel injection are economy and emissions drive-ability but maybe, i am short sighted about this.

The one thing i did pick up from a few pages back was the split system with each set of injectors handling half the revolutions. So two injectors on each cylinder running each fueling alternate revolutions. Which should solve a few of the problems with doing it in the past.

You could also maybe alter the characteristics under overrun even possibly dial in some engine braking.
Maybe include a four stroke switch for slippery conditions and learner racers.

2011 Return of the two stroke. Possibly premature.
http://www.youtube.com/watch?v=goNP9pLHhyU&lc=rwsGLtvui8s1Pt4dgQ7L18qW3Iqbnn2MaWTHlcr08SQ&context=C3714f15ADOEgsToPDskL7BjBrQhia1uTNqMht_TCF

[Bren_chch]

What do you do for a living, Pugs? Archeology? I wrote that stuff 33 years ago! Where did you dig it up?

hahahaa thats classic!!!

umm i been building this engine which i copied off the peter steadman ke125/rg barrel motor with a few teeeennny tinnny changes.

I ran it yesterday in a few races and it went better than i expected, attached it a photo of the piston... to me it looks perfect but what do you guys think?

added a couple of the cool machining photos too.

many thanks

[Yow Ling]

Seems to go alright


http://www.youtube.com/watch?v=bkUBe-DJRu8&context=C3158cb7ADOEgsToPDskK4Cl6zI537eubBVgnq66rw

[husaberg]

hahahaa thats classic!!!

umm i been building this engine which i copied off the peter steadman ke125/rg barrel motor with a few teeeennny tinnny changes.

I ran it yesterday in a few races and it went better than i expected, attached it a photo of the piston... to me it looks perfect but what do you guys think?

added a couple of the cool machining photos too.

many thanks



11th February 2011, 21:41
I got a 29hp engine on triple-r-superbike dyno, the clutch was slipping bad and it was sucking in gearbox oil so i am sure there is a bit more power, i was running a 33mm vmx carb but am going to try a 28mm pwk carb, i have fixed the clutch with a new kit and added stronger springs, also fixed the oil issue with new seals and more GOO around the rotary disk cover. Its running a cr125 ignition which i want to replace with a zeetronic so i can make use of the powervalve and sort a good tune out.

On its first outing it shagged the original clutch kit and then started drinking the gearbox oil but it was still reaching just over 170kph at ruapuna, there were more power available but i ran out of smaller back sprockets.

I had some good help from F5Dave and Peter Steadman.

its in a rs125 chassis

Oh the pipe is a modified tz250 swarzzzz... swerz......... na swarzbrook?? shit cant remember pipe. seems to work pretty awesome, strong power everywhere.

I would actually like to send all my spec/info to wobbly and see if he has any ideas on what else i could do to make it better.

Some pics below.

Is this an annually updated project Bren?:shifty:

Nice work.
So it is 29hp? Or more?
What chassis is it in now?

[Bren_chch]

i pulled it apart not long after that, then it sat for ages.. i got a new piston in it and put back together but i stuffed up the piston/bore clearance, so it sat again. another type of piston in again and some other changed after keeping an eye on this thread over the months.

its in a rg250 frame, feels much much better for me!!

just heading out, will post up some pics in the new frame when i get back

[F5 Dave]

What gas are you running Bren?

[Bren_chch]

What gas are you running Bren?

that was 98.... i know i know u said race gas only!!! :laugh:

[F5 Dave]

unleaded burns a bit darker I think, never really used it, I'd have been expecting a bit lighter for av if the jetting was close, so don't take any chances. Looks like it goes well & looks like a symmetrical pattern.

[Bren_chch]

unleaded burns a bit darker I think, never really used it, I'd have been expecting a bit lighter for av if the jetting was close, so don't take any chances. Looks like it goes well & looks like a symmetrical pattern.

cheers... kinda my thoughts too. next outing will be avgas, also better gearing, will try make a race video.

oh going to fit peters carb and do a back to back, i think the pwk is too small.. 28mm

[trevor amos]

Is there any one out there with an English laguage version of the Frits pipe article , or , alternatively can recomend a good on-line translation site.
Frits no doubt finds it " old hat " but us beginers need all the help we can get . Finally , it`s good to see Neels popping in for a look now and then !

Regards to you all , Trevor

[Frits Overmars]

Maybe you could entice Neels into translating it. After all, our native languages have the same source (Afrikaans stems from Dutch) so no doubt Neels can read Dutch as well as I can read Afrikaans. And no doubt Neels has more English than I do.
Just kidding, I cannot spare the time and I am sure neither can Neels. But just in case someone produces an English translation, I would love to get a copy.

[trevor amos]

There you go guys , who could turn down a request from Frits ! I`m sure one of you clever people out there can get on the case and do a lot of people
a really good turn , i`m sure i`m not the only one .
Any spare time Neels ?

Regards Trevor

[rgvbaz]

Hi ,my names Dave, been lurking here for a while. really enjoying the thread.

I race a 50cc aprilia RS50 2 stroke in the FAB-Racing championship in the UK, I guess our championship is the UK equivelent to bucket racing.

Anyway, I've asked my dad to have go at translating Frits's article. It's been 44 years since he moved back from the Netherlands where he lived for 8 years. Not sure how he will get on with the technical bits as he grew plants out there, he did say he used to think in Dutch in his mind, when he first came back home he had to translate the English word to Dutch for a while so his Dutch was good but 44 years is a long time.

Anyway, I will email it to him and he will see what he can do.

Cheers

Dave

[ief]

Hi all, another lurcker here and me as well want's to say tnx to all who've contributed so far, quick :wavey: to Frits as far as he recals my name anyway ;)

Reason i'm posting is, although i coud try and translate the Frits expansion chamber pdf I thought i'd post this link here first as to me it seems to cover most of the basics and is a good read as well. (and slightly more modern, if there are things not correct i'm sure someone on here will straighten it out :))

expansion chamber theory link (http://homepage.mac.com/rg500delta/deltaphasetwo/Frames/pipe_design.html)

[F5 Dave]

Hi ,my names Dave, been lurking here for a while. really enjoying the thread.

I race a 50cc aprilia RS50 2 stroke in the FAB-Racing championship in the UK, I guess our championship is the UK equivelent to bucket racing.

Anyway, I've asked my dad to have go at translating Frits's article. It's been 44 years since he moved back from the Netherlands where he lived for 8 years. Not sure how he will get on with the technical bits as he grew plants out there, he did say he used to think in Dutch in his mind, when he first came back home he had to translate the English word to Dutch for a while so his Dutch was good but 44 years is a long time.

Anyway, I will email it to him and he will see what he can do.

Cheers

Dave

Hi Dave, welcome aboard [& ief]. We have 2 classes here. F4 & F5. F5 is 50cc proper engines & 100 4 strokes with carb size limit. F4 is 100cc or 125 aircooled with carb limit. oh yeah & 150cc 4 strokes. F4 is the larger of the classes due to bike availability & some sort of compensation I'm sure:msn-wink:.

In NZ we are so isolated by water we have really only english as a primary lanuage & ironically even though there are heaps of Dutchies here most seem to have come so long ago thier kids grew up with English. However we do have an increasingly large S.af population, maybe we will get some response.

[rgvbaz]

Just had a text from my Dad,

He said the article starts as being about a 15 year old boy getting his first moped and wanting to see how it works, from there it led too seeing how the engine works and from there to the exhaust system.

It will be interesting to see how the two translations compare.

Dave

[Frits Overmars]

Hi all, another lurcker here and me as well want's to say tnx to all who've contributed so far, quick :wavey: to Frits as far as he recals my name anyway
Reason i'm posting is, although i coud try and translate the Frits expansion chamber pdf I thought i'd post this link here first as to me it seems to cover most of the basics and is a good read as well. (and slightly more modern, if there are things not correct i'm sure someone on here will straighten it out)
expansion chamber theory link (http://homepage.mac.com/rg500delta/deltaphasetwo/Frames/pipe_design.html)http://homepage.mac.com/rg500delta/deltaphasetwo/Frames/pipe_design.html
This is very good reading!

[rgvbaz]

Hi Dave, welcome aboard [& ief]. We have 2 classes here. F4 & F5. F5 is 50cc proper engines & 100 4 strokes with carb size limit. F4 is 100cc or 125 aircooled with carb limit. oh yeah & 150cc 4 strokes. F4 is the larger of the classes due to bike availability & some sort of compensation I'm sure:msn-wink:.

In NZ we are so isolated by water we have really only english as a primary lanuage & ironically even though there are heaps of Dutchies here most seem to have come so long ago thier kids grew up with English. However we do have an increasingly large S.af population, maybe we will get some response.

Thanks Dave.

Our classes are just about to change for this year. There were four clases in the MotoTeam class last year http://www.fab-racing.co.uk/page3aa.html we raced in the class four which is 50cc in a road based chassis or 128 2 valve aircooled in a road base chassis. The 50's were pretty quick compared to the 4T's eccept for one, a guy called Kev on his RS50 chassised 4T who won.

This year our class will be 50cc liquid cooled only, however the RS125 chassis 50cc's will be in with the production chassis 50cc's, apparently there is a fair advantage to be had with the better chassis.

Here is some you tube of some of our races http://www.youtube.com/watch?v=CaT6RNOI7eQ&feature=related

Dave

[F5 Dave]

All good stuff. I have an antiquated suzi RG50 with a million years development (bit like uk TS50 but watercooled) in an RS125 chassis, but have a Derbi to go in one of these days (Like when I'm finished my F4 100). I'd read a bit about your racing in CMM mag.

[koba]

Here is some you tube of some of our races http://www.youtube.com/watch?v=CaT6RNOI7eQ&feature=related


Looks very good. I like the track.

[pugs]

What do you do for a living, Pugs? Archeology? I wrote that stuff 33 years ago! Where did you dig it up?

hahahaa thats classic!!!
Lol... Oh well, I thought, philosophy needs to be classic:laugh:


Is there any one out there with an English laguage version of the Frits pipe article , or , alternatively can recomend a good on-line translation site.
Frits no doubt finds it " old hat " but us beginers need all the help we can get . Finally , it`s good to see Neels popping in for a look now and then !
Regards to you all , Trevor

Just kidding, I cannot spare the time and I am sure neither can Neels. But just in case someone produces an English translation, I would love to get a copy.
While my dutch is not that good, actually I'm working on it... (need to see dictionary every now and then..:wacko:)

[husaberg]

One of the European corespondents has one of these the HP is not too shabby for either really considering the design of the twin is quite unique.
Shame about the Albion box.


Yes a couple of my single cylinder Alpha bottom end's are on that web site, and the picture you attached of the Alpha test bike with the very early single cylinder engine is one of my bikes although it no longer looks like that. The Alpha twin on the web site is one of 4 machines that "survive", but its not mine. That is the sister bike of the one damaged in the fire, which is being rebuilt slowly by its owner, the frame is now straight thanks to young Sprayson, there is now a replacement gearbox sourced from New Zealand, he has a spare engine, so heading in the right direction. I'm now making a replica Centuri engine since I do not want to trash another original Alpha engine on the race track, heads and crankcases already cast I still have to finish the core boxes for the cylinders, but that could take a week or two yet! My bike is one of the two DMW versions used in the 68 TT, neither of which managed a lap during the race. Another little snippet is the bikes run on a 29 mm Delorto with an 1800 main jet, yes not a miss print, one of the short falls of using a single carb and twin disc valves, however having said that, the final version did manage to produce 48 bhp at the crank, and had an amazing appitite for primary chains.

The Merlin engine in your photo's was very popular with the Kart people, there were 3 versions to my knowledge a 200cc, 250cc and a 350ish cc engine. A very good little engine, but sadly not developed like so many other good ideas.

The Arrow engine is now becoming popular again in Classic Bike racing in the UK, as you said the engine is very similar to both the Adler and TZ, with the same bore and stroke. The bikes currently racing in the UK are much more like the TZ internally, than an Ariel. The Ariel came in multiple shapes and sizes, 200cc, and 250cc with the latter available with the standard single carb, or the twin carb sports version. All bikes had the basic very stiff pressed steel spine from, which was very advanced for its time and trailing link front forks which are very heavy, the Leader had the extra body work for every day transport, and the Arrow was the bare sporty bike. Good machines.

Another interesting British engine was the Royal Enfield GP5 designed by Hermann Meier, which I think was one of the first 4 transfer port engines around, and way ahead of the Yamaha versions, and not counting the MZ boost ports. Hermann was a very clever engineer who also tuned the very succesful TT Arrow ridden by Mike O'Rourke.

Enough now lets get back to modern stuff, so I can revise my designs for the Centuri core boxes!



More here http://www.lortim.demon.co.uk/alpha/index.htm




Here is some you tube of some of our races (http://www.lortim.demon.co.uk/alpha/index.htm)
(http://www.lortim.demon.co.uk/alpha/index.htm)
(http://www.lortim.demon.co.uk/alpha/index.htm)On the You tube clip posted further back i seen this neat idea. The racing footage was also neat by the way as well.

http://www.youtube.com/watch?v=aAN23NNeiJw&feature=related

[gamma500]

Hey all!

I bought some snowmobile engines couple of days ago, and I was surprised to see transfer port dividers also in the crankcases.

Any of this threads readers ever tested these kind of transfer dividers?

[cookie1965]

Anything well just about anything can be made to work given enough time, money and more importantly determination.

I concept is great but why one throttle body?
What is the outcome you are after drivablity, fuel consumption,Tune-ability, emissions or performance. ?
The main issues i see is that carbs are light and simple and relatively specking. Ie no battery/alternator, fuel pump regulator ECU etc.
I am not knocking you because it is great to actually do it rather than just thing about it or just ruling it out.
What sort of fuel pressure are you envisaging?
I remember the Cagiva system involved huge pressures.
The biggest potential advantages i see with fuel injection are economy and emissions drive-ability but maybe, i am short sighted about this.

The one thing i did pick up from a few pages back was the split system with each set of injectors handling half the revolutions. So two injectors on each cylinder running each fueling alternate revolutions. Which should solve a few of the problems with doing it in the past.



Yup, carbs are simple and I don't have any problem tuning them. The bike I'm putting this on (RZ350) has a charging system so no power worries and I have to build a harness for it anyways, might as well do the FI at the same time. I'm doing this more as an experiment - kind of a "can I make this work" kind of thing. The single throttle body concept was for simplicity really. My thinking being that since the throttle body is only responsible for the metering of air not fuel one large TB would be sufficient. I'm not expecting any performance gains, but if I could match the performance with simplified tuning (once base maps are written) and driveablity I'd be happy. Honestly don't know the fuel pressure, I purchased a kit with pump and regulator included. I'll put a gauge on it when it's running to monitor it. I considered 2 injectors per cylinder but decided on a single for the prototype. A low speed/high speed injector system may work better, we'll see I guess. The cylinders are out being bored for new pistons and then assembly, wiring and fuel system to build.

[rgvbaz]

Glad you like the youtube action.

Mind I must try to get into the garage to get prepped for this years races!:yes:

Dave

Ps. The track is Rowrah Kart Track in Cumbria, Its not bad but I prefer Llandow in Wales, then Whilton Mill thats just (2hrs) down the road from me. These are the only three race tracks we use and all are for karts. Some of us do go to the Dutch end of year 4hr race in Croix France http://www.youtube.com/watch?v=L0piJg7cjms&list=UUDbp2Mqd6jONo3pYQ9ZXTXQ&index=2&feature=plcp, been once... it rained... bike blew up! Its still ace mind.

Anyway now back to tuning engines.

[twotempi]

The common two-stroke conrod length ratio is twice the stroke with some variation. For a 50mm stroke engine what is the accepted ratio limit for longer rods.

Calcs show the that the piston acceleration is increased therefore greater stres on the piston pin little end assembly, and also a slightly increased dwell at the top of the stroke.

What are the other pluses anmd minuses of say a 110mm rod with 50mm stroke. What would the mechanical rev limit be estimated to be ??

[nasone32]

longer rods on a two stroke give

-less friction of piston against the cylinder wall, due to different rod angle
-increased time area if restoring port timings after rod change (port durations decrease a bit when you put a longer rod, by restoring them you gain area!)
-increased crankcase volume
-decreased maximum acceleration
-increased weight (usually)

I found a nice paper here (on 4 strokes), with example quantities calculated for various factors, so you have a better idea of what happens :)
http://www.rustpuppy.org/rodstudy.htm

maximum safe revs are hard to tell without knowing the engine, depends on piston+rod weight and strength, crankshaft balancing/stiffness

Personally i'm happy with long rods when looking for maximum power, but on a fixed-ratio 100cc kart I would be careful, they run often out of powerband and a bit higher crankcase compression is useful there (maybe can by fixed with epoxy)... Unfortunately I don't have such experience in karting :(

[wobbly]

For a race engine there are no minuses to a long rod.
Using 110 in the 50 stroke means you are on the money with the Aprilia RSA - that went OK for a 2T.
Increased weight and increased small end load dont mean shit unless you are reving the 50 stroke to 16,000 - then all lighweight parts are needed.
In a direct drive kart engine all the components are very light due to the 22,000 rpm they spin to, and the tradeoff between peak power and
bandwidth is biased in favour of better bottom end, so the case is relatively small.

[SS90]

I see the Europeans have joined in force...this should be good.

[Grumph]

I see the Europeans have joined in force...this should be good.

So what do you count yourself as now ? And where the fuck are you when I've got a bike to test ?

You promised faithfully you'd be available to test anything i built.....

I have doubts though....a couple of years of German food and beer and you'd be bigger than me now....Never get on a 125 again.

[F5 Dave]

and there are tremendous rumblings in Prussia, although that might be something to do with the sausages.

[SS90]

So what do you count yourself as now ? And where the fuck are you when I've got a bike to test ?

You promised faithfully you'd be available to test anything i built.....

I have doubts though....a couple of years of German food and beer and you'd be bigger than me now....Never get on a 125 again.

My leathers do seem slightly more "spray on" these days............

[breezy]

ss 90, way back, in this long thread ,you mentioned and showed pitures of old cast twin transfer ported barrels that you added piston controlled boost/ transfer ports to. is there anywhere on the net which gives any more result based info i can read / down load. thanks in advance...

[ief]

Picture says more than a 1000 words :)

255386

255387

(got them from kreidler.nl forum (http://www.kreidler.nl/forum/viewforum.php?f=5) )

Couldn't find the info you wanted except it's suposed to give some improvement all over the range.

[breezy]

IEF , thanks for the pictures, i guess its all about having a go and hoping for the best. spent alot of time on the barrel im using now, gonna take a lot of bottle to let loose with a grinder and drill my lovley piston.........

[SS90]

ss 90, way back, in this long thread ,you mentioned and showed pitures of old cast twin transfer ported barrels that you added piston controlled boost/ transfer ports to. is there anywhere on the net which gives any more result based info i can read / down load. thanks in advance...

While it is certain that piston controlled boost ports are neither new nor high tech, I am pretty sure I only mentioned them to illustrate some point or another.... possibly the importance of crankcase scavenging I suspect..... All good when it comes to modifying an old, cramped design.

Web based info?

Meh......

While there are some profoundly experienced clever buggers casting wisdom out on the web, my experience is that the best stuff comes from small "cliques" situated in Europe, very little of which finds it's way onto the web. The real smart ones (not only males by the way) are the 50cc brigade around the Nederlands.

[TZ350]

... spent alot of time on the barrel im using now, gonna take a lot of bottle to let loose with a grinder and drill my lovley piston.........

Some photos of the std Suzuki GP125 gully boost port, I would not be to worried about cutting ports into the piston, its fairly easy to do neatly and you can practice on an old piston first.

With the piston in the bore we mark the position of the ports then drill a pilot hole we then use a bigger drill the correct width and by pulling the drill over we get a nice elongated hole, afterwards we clean the hole up with fine paper, its easy to do.

Pictures of a std Suzuki GP125 cylinder and piston and one of our 31rwhp cylinders (estimated 34 crank hp) where the gully boost port has been opened up, the piston is from another motor but you can see how drilling a hole then pulling the drill over makes a nice shaped port.

[ief]

Funny looking cylinder somehow, why did't they make that gully port crank fed in the first place? Am I right in assuming u still use the holed piston with the crank fed boost port, wouldn't that be counter productive flow wise?

And what i was meaning to ask for some time, did u ever get around to using the defconned cylinders as somehow i've got the feeling there might be even more improvement there seeing your 30 hp cyls.

ps: for the record, count me out on the genies part of the dutch tuning community, just here to learn and find inspiration for my mostly theoretical tuning efforts :shutup:

[Grumph]

Holes in cast pistons which didn't have them originally are all about the radiuses and finish....poor finish equals superb stress raiser.

It pays to lift the barrel frequently and keep a record of the hours run when using a perforated piston.
Once a crack is seen, you've got the figure for piston life.

Don't ask how I learned...it's embarrasing.

[TZ350]

Am I right in assuming u still use the holed piston with the crank fed boost port, wouldn't that be counter productive flow wise?

One of the other engines does not have the hole in the piston, but mine does, we are not sure whether it helps or hinders, might do a back to back test some time. But I like the idea of some wind and oil cooling the underside of the piston and lubricating the little end.


And what i was meaning to ask for some time, did u ever get around to using the defconned cylinders as somehow i've got the feeling there might be even more improvement there seeing your 30 hp cyls.

255414

If you mean the cylinder on the right, no, it needs a re-bore, so I have not tried it yet. The cylinder on the left is the one currently on my bike.

I am in the process of making a new short 24mm carburettor from a modified EI flatslide and the next move is to make an engine with a bigger diameter rotary valve so that I can have an inlet port thats fully open for longer.

[breezy]

Thank you all for your time and efforts in showing me how to go about this and maybe i can find and translate some of the dutch web sites to learn more......Im currenty trying a tz350 inspired project to keep myself busy... when i learn how to show pictures on the forum ill let you see, truly bucket style come scrap heap challenge with a bit of "im sure i can get that end mill bit in my wood router"......


(where theres a will theres a way)

[Frits Overmars]

...I would not be to worried about cutting ports into the piston, its fairly easy to do neatly and you can practice on an old piston first.A priceless tip. Never perform a modification you haven't done before on a part you still intend to use.
With the piston in the bore we mark the position of the ports then drill a pilot hole we then use a bigger drill the correct width and by pulling the drill over we get a nice elongated hole."If it ain't electric it can't be good" hmm? Sure, you can do all kind of tricks with drills, grinders, milling cutters etc. But there is nothing wrong with a file.
Two golden rules when modifying cylinders, pistons, etc:
One: stop before you reach the inscribed lines.
Two: wherever possible, do the finishing touch with a hand file. It will save you a lot of errors. And if you are looking for a more 'technical' reason: grinding and milling will in general remove material perpendicular to the direction of flow; you risk producing a surface with a lot of pot holes. Filing removes material in the direction of flow; it will automatically offer a smooth surface to the flow.
Filing is a slow process compared to the various 'electrical' operations. But that is an advantage, not a disadvantage. The goal is not to finish a part in a hurry; the goal is to avoid having to redo it.

[Frits Overmars]

While there are some profoundly experienced clever buggers casting wisdom out on the web, my experience is that the best stuff comes from small "cliques" situated in Europe, very little of which finds it's way onto the web. The real smart ones (not only males by the way) are the 50cc brigade around the Nederlands.Names, addresses, cell phone numbers, photographs! :rolleyes:.

[wobbly]

Its a joy having a woman that likes it on her knees, but imagine one that likes to get her knee down.
I can see all you dirty buggers grinning now - stop it, and get back in the workshop.

[husaberg]

Some photos of the std Suzuki GP125 gully boost port, I would not be to worried about cutting ports into the piston, its fairly easy to do neatly and you can practice on an old piston first.

With the piston in the bore we mark the position of the ports then drill a pilot hole we then use a bigger drill the correct width and by pulling the drill over we get a nice elongated hole, afterwards we clean the hole up with fine paper, its easy to do.

Pictures of a std Suzuki GP125 cylinder and piston and one of our 31rwhp cylinders (estimated 34 crank hp) where the gully boost port has been opened up, the piston is from another motor but you can see how drilling a hole then pulling the drill over makes a nice shaped port.

Frits and Wob and Grumph have probably seen them but does anyone have a pic of the Italian designed by Vincenco Piatti
AMC England manufactured motors made for James/Francis Barnet etc.The ones with the funny piston head port cut outs to control the fuel air charge kind of like a non loop scavenged deflector.Pic posted below. but a bit hard to make out detail sorry.
Because i am pretty sure they were all transfer gully ports as well. Just a trench machined into the cylinder with no cylinder wall to support them. Although i understand the motor was a piece of poo it did have a radial finned head.
In the shed at my old mans there is modified Villiers Cylinder that cut through the sleeve entirely and used the pistons skirt for the outer wall of the cylinder.
I am certainly not suggesting it was a great idea but It was done for a time at least once. Probably not that successful other wise they would be more common..
Note these engine were under-square and had real long skirts.No short skirt for you there wob sorry


http://www.motorcycle-usa.com/289/540/Motorcycle-Article/Memorable-Moto-Francis-Barnett-Cruiser.aspx

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]--> In an attempt to break away from Villiers' monopoly supply of engines, AMC commissioned Italian designer Vincenzo Piatti to design all-new two-stroke engines. Piatti was already known to AMC management through his novel, but breathtakingly ugly, Piatti scooters, but the project was a total mess from start to finish. First of all, Piatti's design - constrained by AMC's demands for cost cutting rather than quality - was very conservative. Second, it was poorly made by AMC and soon gained a strong reputation for unreliability.

[Yow Ling]

Frits and Wob and Grumph have probably seen them but does anyone have a pic of the Itailian (pos French) AMC motors made for James/Francis barnet etc.The ones with the funny piston head port cut outs to control the fuel air charge kind of like a non loop scavanged deflector.
Because i am pretty sure they were all tranfer gully ports as well. Although i understand the motor was a piece of poo.
In the shed at my old mans there is modified Villiers Cylinder that cut through the sleeve entirely and used the pistons skirt for the outer wall of the cylinder.
I am certainly not suggesting it was a great idea but It was done for a time at least once. Probably not that successful other wise they would be more common..
Note these engine were under-square and had real long skirts.

Pretty common in chainsaws and weed eaters.

[wobbly]

I built a mini bike when at high school ( got my picture in the paper - really helped my behind the bikeshed activity's ) that had a James motor.
It had the transfers cut as slots in the liner and the angled cuts in the piston.
Great idea for changing the port timing easily,as I found out,in that I "tuned" it so badly that no matter how hard I reved it, I would fall into a torque hole,with only a 4 speed box.
That started my quest to understand how a 2T worked - still havnt got it nailed.

[husaberg]

I built a mini bike when at high school ( got my picture in the paper - really helped my behind the bikeshed activity's ) that had a James motor.
It had the transfers cut as slots in the liner and the angled cuts in the piston.
Great idea for changing the port timing easily,as I found out,in that I "tuned" it so badly that no matter how hard I reved it, I would fall into a torque hole,with only a 4 speed box.
That started my quest to understand how a 2T worked - still havnt got it nailed.
Note to the younger tuners out-there.
My own limited experience suggests when attempting to "nail it" is too concentrate one the upper inlets or "torque hole". Or for some the exhaust port depending on the model brand. Not my thing.:shit:
If to much effort is spent with the lower front transfer passage a dangerous spreading of the bottom end curve can result, leading to periods of non working :blink:
Wobs bit above with the 4 speed box is intriguing, As my own model A Fancis Barnett (a Fanny B) as they are called) seems to have trouble with the "box speed selector" not functioning i will have to strip it down later and see if i can find the problem.<_<

[Grumph]

After that, it seem redundant to mention that the AMC motors referred to were actually made in France by an outfit coincidentally called AMC....so blame the French again, this time for wob's early sexual adventures.....

[TZ350]

255466

Early 36mm EI carburettor. An interesting thing about these carbs is the 36 refers to the size of the carb at the engine end and its actually 33mm at the slide. I suspect the Lectron carbs are sized this way too. They are both very different to other carbs.

Other traditional manufacturers size their carbs at the slide so apparently in the industry there is no hard and fast rule about how carbs are made or measured.

255468255469

To shorten the carb I cut the front and back off it and pressed in a plug thats the right size for the manifolds we use on the GP engines.

255467

The plug was turned to form a 24mm venturi right behind the slide where carbs are traditionally sized and where people said mine should be measured too. On this carb the front part is a flow straightener and fuel dispensor and the 24mm venturi is the high velocity, low pressure fuel atomiser for better drivability.

I expect any fuel droplets however small will just burst into vapor when they pass through the region of low pressure in the 24mm venturi. In the pressure recovery area after the venturi we should have a very well homoginised mixture of fuel and air being inducted into the crankcase.

255465

There is no main or pilot jet in a EI carb, the fuel metering is done entirely by a needle tapered only on one side, this taper faces the engine and purportedly gives better fuel atomisation than a conventional carb.

The mixture strength on the EI carb is adjusted by winding the needle up or down, a bit like shifting the clip on a conventional needle, and if that's not enough adjustment then another needle with more or less of a taper can be used.

I think that even if this carb flows more air there won't be much if any of a power increase as I think the inlet port itself has become the restriction on air flow into the crankcase now.

255470

An old Suzuki GP125 rotary valve is sitting ontop of my new RV, now thats a very healthy 23% increase in area.

The next move is to build an engine with the bigger rotary valve so that the taller but narrower inlet port stays fully open for longer and can give the specific time area required for the target RPM and BMEP.

[husaberg]

255466



255470

An old Suzuki GP125 rotary valve is sitting ontop of my new RV, now thats a very healthy 23% increase in area.

The next move is to build an engine with the bigger rotary valve so that the taller but narrower inlet port stays fully open for longer and can give the specific time area required for the target RPM and BMEP.
I was suggesting a way via PM the other day for TZ to shorten up the manifold it would have been hard work and was complicated.

I was half way through drawing it up when it occurred to me that this would be better not to mention easier.

Forgive the photo shop but it would be easier to do for real.
I think it should be able to clear the primary gear which is why the simple Aprilia/Rotax style wont work



http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=255474&stc=1&thumb=1&d=1327126086 (http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=255474&stc=1&thumb=1&d=1327126086)
I am not so sure that inside out manifolds are reverse engineering but i like it.

It would be great for TZ to show the box of carbs he has tried on the GP so far.

[Rick 52]

255497

Hi can anybody tell me why I have this strange burn pattern on the crown of my piston ? It has done about 3 meeting including last years GP .The pattern that looks like a number 1 was light carbon and easy to remove ,at Taumanuni 7th Jan it was running rich so I changed the main and it ran much better ..The engine is a TF125 Cheers Rick

[TZ350]

255500
Hi can anybody tell me why I have this strange burn pattern on the crown of my piston ? It has done about 3 meeting including last years GP .The pattern that looks like a number 1

Its an omen from the Gods Rick, best you turn up at the next GP.......

[TZ350]

It would be great for TZ to show the box of carbs he has tried on the GP so far.

255501

Carbs .......

[Rick 52]

Its an omen from the Gods Rick, best you turn up at the next GP.......

Haha cheers Rob but I think I need another 5+ horses to play at the front with the big boys..

[TZ350]

Haha cheers Rob but I think I need another 5+ horses to play at the front with the big boys..

Rick ... you are one of the big boys.

Bring you engine around with the head off so we can put a degree wheel on it and have a look at whats there, maybe there is something that can be done.

[kel]

Bring you engine around with the head off so we can put a degree wheel on it and have a look at whats there, maybe there is something that can be done.

Its already a well sorted kart track racer, dont mess with it.

:psst: TZ I'll slip you a fifty not to touch it.

[TerraRoot]

something of interest:
http://www.drrinc.com/pdfs/higher_compression6.pdf
there's no date and a few of the technical bits aren't explained, but it does involve small aircooled two-strokes so it could be useful (or confusing :facepalm:)