ESE's works engine tuner

[husaberg]

Will do. Currently running 180 which seems to work for the big injector. I already have tried 0 - 90 - 180 - 270 for the small injector , but will try a series of much smaller steps.

Attachment 321202

I now have the Ecotrons EFI throttle body with TPS and Injector all setup to go. It is a conceptual test and if this works better with the small injector firing behind the throttle plate I will see how I can get an injector installed like this behind the ball valve throttle so I can put it back on, I like that ball valve throttle. Dyno is booked for the next few days, so maybe get to try it next week.

Silly question, (as you have likely posted it numerous times) But how does the Ecotrons kit you are using, measure airflow Rob?

[dark art]

Silly question, (as you have likely posted it numerous times) But how does the Ecotrons kit you are using, measure airflow Rob?

Not Rob, but it doesn´t.

Yes. Running a TPS vis RPM ... Alpha-N map

[MotleyCrue]

Yes of course running Methanol would make jetting any type of carb way easyer.
The mixture was being affected by pipe pressure when the piston was at TDC,exactly when the reeds are open and case inflow from the carb is highest.
And yes I think the reeds may have been helping some.
The engine I did the piston cut job on was a SeaDoo 951 running in a stock class at the World Champs in Lake Havasu - and yes we won, and no the trick was never detected.
Pumper carbs can be run on anything, but I havnt seen one with an accelerator pump so it may be difficult to get snap throttle response on a 4T - even with an aux venturi system.
Nearly all 2T engines ( sea,snow,kart,chainsaw ) use pumpers, and I personally have never seen one used on a 4T, but there may be classes I know nothing about like Briggs in USA that use them ?

Just a terminology difference your "pumper carb" is my "diaghragm carb" . In my world a "pumper carb" is a regular 4T carb but with an accelerator pump like a Mikuni TM33 pumper carb.

[wobbly]

OH,I get it.
We call them pumpers as they incorporate the fuel pump that feeds directly into the throttle body.
The strictly correct term is diaphragm carb as you say.

[TZ350]

Page 1520 ....

Searching the forum with google custom search, it even shows pictures

https://cse.google.com/cse/publicurl...90:5pd9xdluxce

Gentlemen, Nitro2tfx produces and sells some of the best and best value for money engine measuring equipment. Have a look at:

http://tfxengine.com/index.html

An air cooled on Meth operates very similar performance wise to a water cooled on petrol, so its a match in heaven.
In fact if its done really well,you can exceed the bmep of a watercooled on good octane fuel, due to the jungle juices very high latent heat of evaporation - and not suffer the usual issues of heat induced power fade.
EngMod will model anything well, it all depends upon the input accuracy, so yes your crap transfer duct geometry is fully accounted for as an input variable.
As you have a dyno you can convert the power figures to crank easy enough, and from the peak Hp rpm you actually see, you can then modify the pipe temp
numbers of that setup, as modeled, to get accurate outputs for future improvements in port or pipe designs.

Does it ever get to the point where it overcools and make consistent jetting difficult?

Sure can, not difficult, impossible as the motor can run so cold that the Methanol does not completely evaporate and the engine runs lean. Any more Methanol fuel to richen things up only makes the engine run colder and leaner. You can get to the point where there is raw Methanol dribbling out the exhaust and the motor is still running lean, been there done that.

I had a Suzuki road racer fitted with RD barrels that ran methanol and the trick was to blend the fuel so that the engine temperature was high enough to evaporate all the fuel. For my RD/Suzuki the ideal blend was 50/50 Acetone Methanol, I expect that other motors may require something different so you will have to experiment but 50/50 is a good place to start.

Acetone has a higher octane rating than Methanol, evaporates better, a latent heat of evaporation about half way between petrol and Methanol and Acetone significantly reduces Methanols tendency to detonation when lean and Acetone very much helps keep oil in suspension in Methanol blends. Current unleaded pump fuel seems to blend with Methanol so probably worth a try. Sit a sample of mixed fuel in a glass jar for a few days to see if it separates out.

Use Yamabond on the cases, the only issue I had was oil seals, some coped with Acetone others did not. Suzuki crank oil seals worked best, Yamaha Teflon lipped seals swelled up and were useless. Test the seals you are going to use in a glass of fuel for several days. After a days racing I used to run a petrol mix very rich in oil through the motor to clean out the hydroscopic Methanol mix so that the crank did not rust. The richer in oil the petrol/oil mix can be the better the petrol will run with the Alcohol jetting.

The way to ensure that you don't get the issue that TeeZee describes is to run as high com as you can,and then tune to achieve reasonable egt numbers.

The optimum com-egt is easy enough to dial in on a dyno - but without the egt telling you what is going on then you are working in the dark.

Methanol will run very rich with no power loss,but if you choose say 850* as a baseline and jet to get that, then go up in com and rejet to again get that same egt the power generated will tell you if you are on the right path or not.

Lectrons do have very very good atomization from the flat needle, but the powerjet nozzles are no better than a normal carb. Thus you need to run as rich as you can on the needle and just fine tune with small powerjets.

This can be helped a lot by cutting the nozzle exit at 45* facing downstream, and then drill a small 0.15mm hole in the front side about 5mm up from the end.

The other trick is to run twin powerjets and rpm switch one with an inline solenoid,thus getting the rich mixture needed at peak power, then leaning off over the top of the pipe.

When i say brake dyno i mean an eddy current or similar that allows both constant rpm tests and normal 'runs'... Im sure that doing only constant rpm tests is not ideal. Personally I do a combination of both to tune an engine and so far it has worked well for me, especially when tuning the low throttle area that TZ was talking about... in saying that ive only ever had an eddy current dyno, never an inertia-only dyno, and have developed my own methods of tuning without ever seeing first-hand anyone else's process for tuning a two stroke... maybe its a case of ignorance is bliss, however i find my process to be very quick and very reliable for a wide range of engines.
I find that the lambda sensor is a little slow to react at low revs and part throttle. Its fine at higher revs and higher throttle. By holding the engine at a certain rpm point for 3-5sec at each throttle position it gives the readings time to stabilise and gives much better, more repeatable data. I start by doing a range of fixed rpm tests at different throttle openings, with the revs building higher each test... eg 4000, 6000, 8000, etc at 1/8, 1/4, 1/2, 3/4, full throttle ... By doing this you can easily see the areas that need changing (pilot, slide, needle diameter, clip position, needle taper, main jet, etc). If there is a serious problem with the tune you will always catch it before doing damage as youll see AFR's begin to lean out or detonation begin to show before you get too high in rpm. Once ive done basic tuning like this then i do full runs and constant load testing and fine tune if necessary, but these are normally only very minor changes.



Whether the AFR reading is showing true AFR or not doesnt really matter, the numbers can still be used to tune an engine... around full throttle and peak torque it is fairly reliable to use ~12.5:1 and leaner readings below that, down to around 13.5-14:1 at part throttle/low rpm. Of course you still need to use experience and 'feel' to do the fine tuning but the AFR numbers will get you close. Even if the engine is not actually seeing 14:1 at part throttle/low revs, its still a repeatable data point that can be used to tune an engine. Its certainly a lot better than guessing, especially when tuning the part throttle areas.

My main question to TZ though was why he wasnt using AFRs to tune his engine? Since he has employed a lot of technology so far it seems only a small extra step to be using a wideband O2 senor to help with the fine tuning as it will save a lot of the guess work.

+1 the above.Adding that putting the Lambda in the stinger, seems to be way more stable and repeatable when logging the A/F data.

Using data this way is something that you really dont appreciate how good it is until actually doing it.
Hence TeeZees surprise when I related that every time you change a small item in the engines tune - the dyno result for sure is not telling you
really what you want to know, unless you rejet every time to hit a predetermined baseline.

As Jan Thiel said, most all of the pipe testing at Aprilia was a complete waste of time,when he finally realized alot of the power differences were down
to how the egt reacted to that pipe.
Not that the pipe was "better " for some aspect of scavenging, or trapping efficiency in making more or less power.

Hi.

I'm not allowed to start a new thread, so i will risk an eye..and ask here, if inappropriate please delete.

I have been looking in many books about twostroke engines. and also searched on google, but i never found a definitive answer.

Many gokarts run coolant temperatures around 50-55 degrees C, the same goes for outboard engines, and some run even colder.
I have read about many road race bikes, from 50cc to much larger bikes, that also seems to run at these same temperatures.

Why it is so ? Do twostrokes make most the power within this particular temperature ?

Best regards
KKT

This.
Jan Thiel has tested this at Aprilia, up to even running constant tap water through the cooling system.

The cooler the water, the cooler the case and more importantly the cooler the transfer and Ex port ducting.
This maintains charge density, as well as keeping cool the slug of A/F sitting in the Ex duct waiting to be shoved back in
by the rear cone wave action.
With a new water regime I developed for KZ2 kart engines we run between 40 and 45*.
A 125 cylinder will drop at the very least 2 Hp, when lifted from 50 to 60*C

I originally built the BSL crank with integral pins ( it made the engine 17mm narrower - big deal )
Sadly no matter how it was done, with big radi and shot pienning etc the bastard pins kept cracking.
This was due to some form of harmonic or torsional twist from firing 2 of the 3 cylinders together.
In the end I tried a crank with the same dimensions ie only 12mm of press fit on the side where the pin originally was one piece.
We made a jig that kept the pin dead square in the crank hole, and tigged it right around the outside face.
Never had a crank issue after that.

So I would suggest spark eroding new pin holes, in the integral side,and welding in new pins may in fact work.
But from memory the Honda and the RGV/RS250 may be even thinner than 12mm.

One thing to be aware of - the original crank had the pin holes on the non integral side moved inward 0.008mm,as when the pin was pressed in
the wheel material would bulge outward,changing the stroke length by that amount.
Thats not an issue if both sides are pressed in, and both wheels are identical.

In this case it might take a couple of cranks to get the new hole position dead on such that the thing will straighten correctly due to the thin press width.
Having the stroke lengths not matching is easy to detect, with 2 dial gauges on each end of the same axle, both will rise and fall together - impossible to correct.

Measuring that 0,008 mm would be pretty hard to do most normal measuring gauges go to 0,01mm , unless You are talking inches then 0,008 it's 0,02mm but would that make a big difference? Guys here used to be doing thing like this on RZ cranks since it was cheaper than buying new one from overseas and they were not that available like they are now.

You are not measuring it at all, you would be programming a CNC spark eroding machine to bore the pin hole at a reduced the stroke of 0.008mm.
But if the wheels are thinner than 12mm as the BSL ones were, then 0.01 would probably be closer.
And yes 0.02mm runout in a crank is nowhere near "straight ", it would destroy the main bearing and or fret the cases due to the wobble in no time.
This is why I have probably 10 RZ cases that are junk, because the main bearing journal faces are worn oval, from crank rebuilders who didnt know what they were doing.

Not saying you're wrong Wobbly, but even at ,04mm shouldn't fret or damage cases.

Crank rebuilding is an art, I do a lot of singles, and it's not uncommon to see them come out with 5 hours run time at ,15mm runout.

You put a hairdryer to a crank with ,02mm runout and it will move almost twice that

The problem with the twin is that if you are prepared to accept 0.02mm or 0.03 runout like Yamaha says , then this can be at both ends.
It can also easily be on opposite sides, so in effect you then have 0.06 runout across the outer mains - this is why the tunnels are wreaked, being oval or with no crush
in most every old RD/TZ/RZ case I measure these days.

Edit - yes I agree about cranks moving after being run, but in my opinion this is due to having excessive amounts of hammering to get them " true ".
The metal in close contact is very springy, and I have found that if the wheels are held dead in line in a die set so that there is no need to hammer the shit out of them
they dont move at all.
If hammered they will always spring back a little in the direction they came from.

fs1 problem fixed... in the virtual world that is (inlet tuning, inlet tuning and inlet tuning.... mostly) Had a lot of aha moments, always good.

But have 2 things I can't seem to solve myself. First, I made a pipe with ATAC and it gave 12% more power, that is with the latest beta, even with a wrong collector (bends where wrong) Anyone else noticed this or should I be aware of an easy to make mistake or?

Second is the membrane and resonant frequency. When modeling and measuring my tomos I noticed the membrane was way to stiff so I gave it some more free length, still way above what would be concidered ideal but in practice this didn't work at all, bike started '4stroking' at higher revs so my conclusion was that they didn't close fast enough. (though it could (could it?) be something else...)

edit: lol, something popped in my mind, inlet tuning? The pipe between carb and cilinder is pretty long on the tomos. (but still, engmod didn't show a problem as far as I am aware)

Any thoughts on that one?

The 1st harmonic of the reed frequency can be up to around 15% less than the peak Hp rpm.
This frequency is reduced by increasing the petal length or decreasing its thickness.
In EngMod you must be careful that the petals do not smash into the reed stops, as this causes easily seen erratic tip
lift from one cycle to the next.
You can still run the thin reeds but move the stops further way.
Intake length is easily seen in that at the rpm you want to tune for, the case pressure ( red ) goes negative at the same time the
carb / manifold / reed reflecting wave goes positive ( yellow ).
This helps open the reeds quickly, as the piston begins to rise.
If the engine 4 strokes in the top end with a reed change, this may signify that the air corrector isnt big enough, or that the main jet is simply too big.
But if the reed frequency is well above where it should be, then you may have a big mismatch with the intake tuning,that causes the jetting to go to hell as well.

Wobbly, Frits, Jan, we've been given figures for how much power the Aprilias were making at the peak of GP125. How much were the Honda's making?
They continued to use reed valves to the end on their factory bikes too right?

Would love to hear more about their engine development towards the end of the series life. We generally only hear about the 90's.

The Honda RS250 that was a full factory backed effort ( with several HRC and Showa technicians in the Team Scot tent ) in the last year of 250GP, I know finally for the first time had
almost normal length longer rods ( 109 I believe ) and the pipes were for sure fatter than had been used ( and published ) previously.
The engine was quicker than any previous effort, but was still down on power ( and thus top speed ) compared to the Aprilia.
It did however handle superbly, and the rider Aoyama, who subsequently achieved nothing of note on several GP machines, could cut good enough
lap times to be consistently at the front of the field.
Well meaning idiots back at the factory R&D dept had managed to slow down the Aprilia performance in comparison to Jans package, so that did nothing to help.
Sadly the Aprilia team riders detracted from each others efforts, and basically gave away the title to Honda by default.
If SuperSic had been in the field , I believe he would for sure have blitzed the title again.

did Honda crush Aoyama's RS? or have they moved away from doing that these days?

Looks like it's in the honda museum

Wobbly, What direction did you decide was the best to rotate this disc in this situation?

The rotary valve could be spun either way in that case.
The engine sits with the crankshaft vertical ie rotated 90* anticlock to the pic, and the carb would be also vertically in line with that.
Thus as the slide opens it would flow along the manifold floor to the roof of the port - making no odds as to what side of the port was opening or closing.

Does anyone (Wob?) have dimensions of the mufflers for the 125 engines gp or karts? I remember there was one drawing here but was posted not on kiwibiker server and got lost.

All the GP bikes used mufflers with the perforated core a slip fit over the stinger tube OD.
The tuneability is gained in that mid power is enhanced if the perf is the same size as the stinger, top end is enhanced if the perf is slightly larger
for high speed tracks needing top speed, not acceleration.
In karts there is only 1 choice now - most stingers are around 26mm OD, and there has always been 2 choices of perf size.
The early versions were like GP ones where it slipped over the stinger, but later versions were developed with a 40mm core size.
The stinger U tube is around 300mm long and this, when dumped into the big core size makes hugely better overev power.
The first one I tried increased power at 14,000 by 15Hp,up to 40 from 25.
The newly homologated compulsory mufflers are slightly longer, but all have the big core as its alot quieter as well. so I have lost my advantage
in knowing that the bigger size was better as most used the smaller old version previously.

Wob, you mentioned some time ago to do a heat barrier coating on the piston crown and the bowl in the head. I know that the cart boys change their pistons more often than their pants.... So if it lasts for let's say 3 hours hard running, all is fine. But for a bike how long will that coating be durable, any experience?

The ceramic heat barrier coatings I have never seen or heard of it failing.
You only coat the piston in the bowl area, NOT in the squish band - same in the head.

Thank's Wob, got it. The squish needs to get rid of the heat, that's the reason not to coat, right?

The ceramic coating reflects the heat back to the gas boundary layer, this is fine in the chamber as it means more energy is used to create gas expansion.
But the boundary layer in the squish will detonate if the trapped end gases are heated by a hot surface ceramic layer.

[husaberg]

Silly question, (as you have likely posted it numerous times) But how does the Ecotrons kit you are using, measure airflow Rob?

Not Rob, but it doesn´t.

The reason I asked is, conventional carbs do. (Well at least respond to it anyway.)

[Yow Ling]

The reason I asked is, conventional carbs do. (Well at least respond to it anyway.)

They estimate it from a table that considers rpm and throttle position , this is the alpha N thing, other methods are MAP and RPM, then some are able to run in a closed loop with lambda sensor some of the time and alpha n the rest of the time

[husaberg]

They estimate it from a table that considers rpm and throttle position , this is the alpha N thing, other methods are MAP and RPM, then some are able to run in a closed loop with lambda sensor some of the time and alpha n the rest of the time

Some also just use a airflow meter. I understand the concepts, I just wonder if TZ needs something a little more Sofishtickate'ed
cold wire, hot wire, flapper valve, plus some other ones that I can't spell so well

[TZ350]

No ... I don't use an airflow meter nor is it very suitable for making the sort of short inlet tract needed for a high performance two stroke.

This is the way I understand it.

There are three common mapping methods. The MAF table, VE table and Alpha-N table and they can be mixed and matched. No map is perfect every where so at low throttle settings an ECU might use the VE map and then swap to the Alpha-N map at larger throttle openings. This mixing and matching can utilize several fueling maps. There can also be other maps, like required Lambda, ignition timing and power valve settings and cold start enrichment, injection end map Etc.



The greatest changes in air flow occurs below 40% throttle opening and is where changes in air flow has the greatest definition and direct air flow measurement is most useful. Above 40% throttle, the changes in air flow are less well defined and throttle position gives better definition.



The manifold air flow (MAF) table axis are RPM and physical weight of air (Load) as calculated from measured air flow and air temperature. The table is populated with the required Lambda values at each point.

When the ECU uses the weight of the measured air to calculate the required fuel to meet the mapped Lambda value specified and then uses an O2 sensor to see if it got it right, then this is a self correcting closed loop system.



The axis of a volumetric efficiency (VE) table is manifold absolute pressure (MAP) and RPM. The map itself is populated with the Volumetric efficiency values of the engine for each point. The volumetric values are calculated (or estimated) from the dyno torque curves for that engine at various throttle settings.



The axis of a Alpha-N map is the throttle position (TPS) and RPM. The map is populated with Load (anticipated actual combustion-able air) at each point. This "Load" is just a dimensionless number that does not relate to the actual weight of air trapped in the cylinder on the compression stroke, other than 120 indicates twice as much "Load" (trapped combustion-able air) as 60 does.

Because air flow in a two stroke inlet is so violently erratic mass air flow (MAF) and manifold absolute pressure (MAP) are not practical measurement methods so that leaves the Alpha-N approach of TPS and RPM with "Load" values for each point of the map.



To get started on developing a Alpha-N map, each "Load" of air value can only be more or less guessed at, maybe from riding the bike or dyno runs or simulated two stroke delivery ratios and the map Load values are then adjusted until things run successfully.

I am working with an Alpha-N map. Alpha-N is not supposed to be that great at low Load but pretty good at all out performance.

[Flettner]

It would be interesting to have a MAP "sampler", ie only measure air pressure between a certain crankshaft degrees when there is a useful pressure to measure. Turned off at all other parts of the cycle. I was going to try this but I could only do it with a mechanical method so didn't bother. There must be some electronic way to have the MAP sensor only take a reading when you tell it, not all the time?
And or intermix that information with a smoothed exhaust pressure.

[marsheng]

It would be interesting to have a MAP "sampler", ie only measure air pressure between a certain crankshaft degrees when there is a useful pressure to measure. Turned off at all other parts of the cycle. I was going to try this but I could only do it with a mechanical method so didn't bother. There must be some electronic way to have the MAP sensor only take a reading when you tell it, not all the time?
And or intermix that information with a smoothed exhaust pressure.

You measure the pressure over the full crank and then interpret the results from the data. The question is, does the MAP have the frequency response to follow the pressure changes ?

When in the manifold, it is measuring average.

Here is a fast one

http://www.omega.com/pptst/PX105.html

[nitro2tfx]

You measure the pressure over the full crank and then interpret the results from the data. The question is, does the MAP have the frequency response to follow the pressure changes ?

When in the manifold, it is measuring average.

Here is a fast one

http://www.omega.com/pptst/PX105.html

The equipment we have does exactly that and a whole lot more (combustion/intake/exhaust pressure tuning per degree), but it is for R&D and tuning (dyno or short races), not really something you would leave on the bike permanently as a control input.

The referenced Omega sensor is far too slow for per crank angle degree data.

[husaberg]

No ... I don't use an airflow meter nor is it very suitable for making the sort of short inlet tract needed for a high performance two stroke.

This is the way I understand it.

There are three common mapping methods. The MAF table, VE table and Alpha-N table and they can be mixed and matched. No map is perfect every where so at low throttle settings an ECU might use the VE map and then swap to the Alpha-N map at larger throttle openings. This mixing and matching can utilize several fueling maps. There can also be other maps, like required Lambda, ignition timing and power valve settings and cold start enrichment, injection end map Etc.



The greatest changes in air flow occurs below 40% throttle opening and is where changes in air flow has the greatest definition and direct air flow measurement is most useful. Above 40% throttle, the changes in air flow are less well defined and throttle position gives better definition.



The manifold air flow (MAF) table axis are RPM and physical weight of air (Load) as calculated from measured air flow and air temperature. The table is populated with the required Lambda values at each point.

When the ECU uses the weight of the measured air to calculate the required fuel to meet the mapped Lambda value specified and then uses an O2 sensor to see if it got it right, then this is a self correcting closed loop system.



The axis of a volumetric efficiency (VE) table is manifold absolute pressure (MAP) and RPM. The map itself is populated with the Volumetric efficiency values of the engine for each point. The volumetric values are calculated (or estimated) from the dyno torque curves for that engine at various throttle settings.



The axis of a Alpha-N map is the throttle position (TPS) and RPM. The map is populated with Load (anticipated actual combustion-able air) at each point. This "Load" is just a dimensionless number that does not relate to the actual weight of air trapped in the cylinder on the compression stroke, other than 120 indicates twice as much "Load" (trapped combustion-able air) as 60 does.

Because air flow in a two stroke inlet is so violently erratic mass air flow (MAF) and manifold absolute pressure (MAP) are not practical measurement methods so that leaves the Alpha-N approach of TPS and RPM with "Load" values for each point of the map.



To get started on developing a Alpha-N map, each "Load" of air value can only be more or less guessed at, maybe from riding the bike or dyno runs or simulated two stroke delivery ratios and the map Load values are then adjusted until things run successfully.

I am working with an Alpha-N map. Alpha-N is not supposed to be that great at low Load but pretty good at all out performance.

The kits seems to contain a MAP sensor, so I am confused.
http://www.ecotrons.com/products/2_s...injection_kit/
I see they have a small electric oil pump available as well Rob
http://www.ecotrons.com/products/sma..._turbocharger/

[TZ350]

The kits seems to contain a MAP sensor, so I am confused.
http://www.ecotrons.com/products/2_s...injection_kit/
I see they have a small electric oil pump available as well Rob
http://www.ecotrons.com/products/sma..._turbocharger/

The Ecotrons oil pump draws to much current for my limited system. The diaphragm pumper you suggested looks to be working Ok.

The basic kit was originally for 4T's running a VE and Alpha-N map. For 2T's the VE map is switched off and the MAP sensor and inlet temperature sensor are used by the CPU to correct for day to day RAD relative air density changes.

[Brett S]

The Walbro Wt-813 Carb used on 25cc r/c engines has an accelerator pump built in.
It has a flat on the throttle shaft which pushes the accelerator pump when opening throttle quickly.