ESE's works engine tuner

[Frits Overmars]

I have resorted to using an original Suzuki GP125 unit with two 6Volt lighting coils wired in series. Its a very heavy flywheel compared to the KX80 one that I am using now... How high are you going to rev that flywheel, and is your hospital insurance up to it? (I'm not kidding).

[Muciek]

If You could swap this flywheel and stator there You would have over 130W of power http://www.ebay.com/itm/ROYAL-ENFIELD-12V-4-WIRE-ALTERNATOR-AND-ROTOR-/221166237891?pt=Motorcycles_Parts_Accessories&hash=item337e88f8c3&vxp=mtr

We use it in our engines, we rev them to around 7000 rpm. I can help You with wiring and regulator schematics ect. Flywheel weights around 800g.

Here is picture how You need to mount pickup and trigger. You can use one from Chinese scooter just need one with 2 wires or You could use that original one from suzuki.

297590

[TZ350]

How high are you going to rev that flywheel, and is your hospital insurance up to it? (I'm not kidding).

Had one to 12k before but, Yess...... I am a bit concerned too.

[TZ350]

If You could swap this flywheel and stator there You would have over 130W of power http://www.ebay.com/itm/ROYAL-ENFIELD-12V-4-WIRE-ALTERNATOR-AND-ROTOR-/221166237891?pt=Motorcycles_Parts_Accessories&hash=item337e88f8c3&vxp=mtr

That looks very interesting.

I will be running to 14K so twice the rpm means T quadruples.

297591

That is four times the centripetal force required at the flywheel rim to hold the magnets and the rim itself in at 14k than there was at 7k but at least the explosion looks more contained with the Enfield setup. A smaller diameter rotor at the same rpm would reduce T by reducing the rims velocity.

The Enfield looks promising, Thanks.

[Muciek]

But we don't use them in Enfields. It's same setup as one used in vintage engine from here , and since the 40 year old magnets are not strong enough to produce enough power we use this. 7k in standard engine that is used to touring,and in tuned engines we rev it over 11k and it's ok.

[TZ350]

It's same setup as one used in vintage engine from here, and in tuned engines we rev it over 11k and it's ok.

Great..... I will get one, thanks.

[wobbly]

This is what you need - 100mm dia kicks out about 8 amps,have run them over 12,000 for ages,got one here with a reg if you want one.

[wobbly]

That tandem twin CAD rendering has a small problem, the cranks don't counter rotate - I see issues with the rider not being able to hold the bars.

[Ocean1]

That tandem twin CAD rendering has a small problem, the cranks don't counter rotate - I see issues with the rider not being able to hold the bars.

Meh. Just bump the constraints on the CAD rider biceps.

[Flettner]

Not counter rotating, but 180 degree firing tandem is smooth ( enough ). I have made one and run it on my gyro, certainly a lot smoother than the 180 degree parallel twin I have now ( without the ballance shaft ). The problem is the gear to crank attachment, there are a lot of harsh load reversals.

[TZ350]

This is what you need - 100mm dia kicks out about 8 amps,have run them over 12,000 for ages,got one here with a reg if you want one.

Deal Done - Thanks Wob

[husaberg]

That tandem twin CAD rendering has a small problem, the cranks don't counter rotate - I see issues with the rider not being able to hold the bars.

Wasn't the KR250 Kawasaki (road bike)non counter rotating though?
Never rode one or actually never seen one in the flesh either......
the cad rendering i couldn't open the link, so not sure what it was about, could have just been folly......
I did lead me to something else though........

[wobbly]

In an inline tandem twin,the only way to get the counterweights to cancel each other when both pistons are at 90* down and up the bore,is to have them counter rotate.
The original Kawasaki 250 tandem race bikes initially fired at 180* and shook so bad the frames cracked continually and the riders ( Mamola and Ballington who came here with them )
got blurred vision.
Once they fired both together with counter rotating cranks they were no problem at all.
The Rotax tandem as was used in bikes and in SuperKarts still, has counter cranks for super smooth no vibes running.
The Exactaweld had a very clever setup with an extra gear to allow counter cranks and have rotary valves on both sides.

[Yow Ling]

Wasn't the KR250 Kawasaki (road bike)non counter rotating though?
Never rode one or actually never seen one in the flesh either......
the cad rendering i couldn't open the link, so not sure what it was about, could have just been folly......
I did lead me to something else though........

Yes , the roadbike was like the RZ500 the cranks were both meshed into the gear on the clutch basket.
Not so many left now

[husaberg]

Yes , the roadbike was like the RZ500 the cranks were both meshed into the gear on the clutch basket.
Not so many left now

Like this.....

[F5 Dave]

Blurry memory, think Armstrong were experimenting with 180 on modified 256. not sure they got far.

[F5 Dave]

How high are you going to rev that flywheel, and is your hospital insurance up to it? (I'm not kidding).
A good call. We used to race on airfields. Suzuki cranks used to shear with std flywheels when you revved them much past 11k.

I saw one once, bit like the ballbearing spun up with an airline; it dropped on the ground & sat still for a moment, then shot off like MJ.Fox's Delorean hitting 88. Luckily no one was in its path. We never found it.

[husaberg]

Blurry memory, think Armstrong were experimenting with 180 on modified 256. not sure they got far.

Armstromg did their own motor and a 350 as well I posted the patterns a while ago.
I'm pretty sure I posted the armstrong story eons ago. Could dig it out.
They could have done a 180 not sure.....
pic of the Exactweld primary on last attachment

[husaberg]

Armstrong stuff that would not fit.

[Kickaha]

I saw one once, bit like the ballbearing spun up with an airline; it dropped on the ground & sat still for a moment, then shot off like MJ.Fox's Delorean hitting 88. Luckily no one was in its path. We never found it.

Diesel Pig had one of his MB flywheels pass him going into the hairpin in one race

[wobbly]

For chassis packaging and getting the front pipe away from the front wheel, doing it the down angled KR250 way, but with the Rotax tandem gear setup and the
gearbox stacked underneath would be very trick.
But for a real super trick setup plant a pair of RSA cylinders side by side with a rotary valve offset out each side of the case - or maybe do it with a single rotary valve in the middle
like many older Ski engines had.
Bartols parallel twin firing at 90* with a balance shaft was technically superb, but if it could have been done with RVs on the back replacing the reeds,then Honda should never have won the final GP250 year
using a rider that now cant ride his way out of a brown paper bag..

[Drew]

For chassis packaging and getting the front pipe away from the front wheel, doing it the down angled KR250 way, but with the Rotax tandem gear setup and the
gearbox stacked underneath would be very trick.
But for a real super trick setup plant a pair of RSA cylinders side by side with a rotary valve offset out each side of the case - or maybe do it with a single rotary valve in the middle
like many older Ski engines had.
Bartols parallel twin firing at 90* with a balance shaft was technically superb, but if it could have been done with RVs on the back replacing the reeds,then Honda should never have won the final GP250 year
using a rider that now cant ride his way out of a brown paper bag.. I think that's a bit tough on Aoyama. I think he rode the 250 brilliantly, but had some bad luck when it came to going 4 stroke.

[Frits Overmars]

....then Honda should never have won the final GP250 year Honda was handed the final 250-title because of Aprilia's policy to lease works bikes to several independent teams. Their riders battled each other for points (and on more than one occasion ran each other off the track) and the slower Honda profited.

[Drew]

Honda was handed the final 250-title because of Aprilia's policy to lease works bikes to several independent teams. Their riders battled each other for points (and on more than one occasion ran each other off the track) and the slower Honda profited.

That's very cynical. Had the best rider been on an Aprillia, he should have won. End of.

[diesel pig]

Diesel Pig had one of his MB flywheels pass him going into the hairpin in one race

It wasn't a MB (I have ever lost a MB flywheel) it was a GP100 because they have f**ked up gear ratios, I went one gear too many down it did million revs and bang straight out of the cases.
It pass me into the hairpin.

[jasonu]

Diesel Pig had one of his MB flywheels pass him going into the hairpin in one race

Yeah one time at (band camp) Manfield I saw Ray Wilsons flywheel come off and came uncomfortably close to beaning Pete Sales who was flagging. F5 you were there, the same day you rode my first version TZR100.

[wobbly]

The best rider, Super Sic should have won the title - but several DNFs and a DNS in the first race,not generally his fault ruined the season.
He had more wins and poles than Aoyama, who generally won when the other quick Aprilias werent even racing him.
When the quick satellite teams all managed to not take each other out Aoyama came 4th or worst.
Frits is dead right, the satellite teams Vs the factory,cancelled each other out ,points wise,so many times they gave the title to Honda.
When Sic and Aoyama went 4T who was at the front and who was down the back - bloody obvious, still is , and nothing to do with luck in my view.

[Drew]

The best rider, Super Sic should have won the title - but several DNFs and a DNS in the first race,not generally his fault ruined the season.
He had more wins and poles than Aoyama, who generally won when the other quick Aprilias werent even racing him.
When the quick satellite teams all managed to not take each other out Aoyama came 4th or worst.
Frits is dead right, the satellite teams Vs the factory,cancelled each other out ,points wise,so many times they gave the title to Honda.
When Sic and Aoyama went 4T who was at the front and who was down the back - bloody obvious, still is , and nothing to do with luck in my view.

Stick to building engines, you suck at understanding a race season versus a single meeting.

If Simoncelli had been the be all and end all that season, no one would have been near enough to fuck his season.

Your argument hinges on the very point I made. It implies that the bike didn't have anyone particularly good on it, since anyone on the same machinery could throw a spanner in the works.

[TZ350]

It wasn't a MB (I have never lost a MB flywheel) it was a GP100 because they have f**ked up gear ratios, I went one gear too many down it did million revs and bang straight out of the cases.

Did it come off the taper or snap the end off the crank?

[diesel pig]

Did it come off the taper or snap the end off the crank?

Came off the taper.

[Drew]

Came off the taper.

Wonder if a second or gruntier key wouldn't stop that happening.

[F5 Dave]

Yeah one time at (band camp) Manfield I saw Ray Wilsons flywheel come off and came unwasf close to beaning Pete Sales who was flagging. F5 you were there, the same day you rode my first version TZR100.

Oh don't remember that but I remember riding your bike clear as if was this afternoon. opened my eyes to what was possible. Seen cranks sheared off clean at the crankweb. Always a big flywheel attached. At least 3 suzukis

[husaberg]

Keys don't hold on stuff, the taper does...... if it came off the nut was loose and or the taper was shagged. keys are only the locating device on flywheels.
lap it on, nut up tight, they stay there....... I learnt that lesson after I lost my flywheel a couple of times:bleh:

[Kickaha]

if it came off the nut was loose and or the taper was shagged.
Could have been either Diesel Pig was always hard on gear

[jasonu]

Wonder if a second or gruntier key wouldn't stop that happening.

I wonder if PROPERLY torqueing the nut to the shaft might have stopped the flywheel coming off.....

[Muciek]

I have a question about boost porting (picture on the bottom of post). Does this type of boost port grinded in liner in depth around 5 or 6mm is worth doing ? I tried this one back few years ago but I was more in style "do a shitload of ports in cylinder " didn't even know that something like STA is existing :wacko:
And I'm attaching a photo of a piston which was used around 150km, would this help to get the black spots off the piston? Boost port cannot be any wider because ring pins are 2mm from it. Ducts are "crappy ones" not much to be done with them. Thanks in advance. ;)

297642297643

[wobbly]

So Sic won 6 races in 2008 and took the 250 title, by your way of explanation Drew then he was a genius that year.
Trouble is he won 6 races in 2009 and lost the title, as so many of the other points were shared out between Aoyama and the Aprilia satellite teams with so called no names on board.
One race has shit all to do with it - explain then the 2006 Moto year where there were 8 race winners, Hayden won 2 and took the title.
Were all those riders only average then - tell Rossi that.
I still come back to the later results, short lived as they may have been, where Sic was on the Moto pace instantly, Aoyama was and still is nowhere, his accident hurting his back badly made no difference before or after.

[husaberg]

I have a question about boost porting (picture on the bottom of post). Does this type of boost port grinded in liner in depth around 5 or 6mm is worth doing ? I tried this one back few years ago but I was more in style "do a shitload of ports in cylinder " didn't even know that something like STA is existing :wacko:
And I'm attaching a photo of a piston which was used around 150km, would this help to get the black spots off the piston? Boost port cannot be any wider because ring pins are 2mm from it. Ducts are "crappy ones" not much to be done with them. Thanks in advance. ;)



Yamaha TD1 b or C had that style, i have some drawings somewhere but they look exactly like what you have posted out of bell......... worth while? not a clue......

[wobbly]

The auxiliary ports fed thru the piston do " work " in that they are better than none at all if aimed correctly but the flow is very compromised
having to get thru the hole and into a slot.
Can you give us a picture of the cylinder base - is it possible to cut B ports with ducts all the way down to the case.
These would exit directly across the piston, as opposed to working like auxiliary boost ports aimed upwards next to the main boost.

[Muciek]

There is pic of base. Not much space to do anything. You mean to do something like on second photo, but aimed like boost port(ie 60*).



297651297652

[F5 Dave]

I wonder if PROPERLY torqueing the nut to the shaft might have stopped the flywheel coming off.....
Only takes a little pick up to stop the taper working, quick lap (dance?) should fix, but won't help when the flywheel ejects still firmly gripping the shaft (Ooo-er vicar:gob:)

[Yow Ling]

Only takes a little pick up to stop the taper working, quick lap (dance?) should fix, but won't help when the flywheel ejects still firmly gripping the shaft (Ooo-er vicar:gob:)

A wee zap with the mig should stop it falling off

[TZ350]

Keys don't hold on stuff, the taper does. keys are only the locating device on flywheels. lap it on, nut up tight, they stay there.......

Duzel Solderflux (acid) in the taper helps too, the rust created by the flux expands and locks the tapers together.

[speedpro]

I have used Loctite bearing mount on the taper of a rough corroded crank. Bit of a bastard to get apart but never came off by itself.

I've seen GSX1100 generator rotors win the race to the end of Pukekohe's front straight.

[Frits Overmars]

The first Rotax tandemtwin engines (I received the first two in December 1980) had long tapers on the crankshafts and in the large primary coupling gears. In addition Rotax seemed to have used the strongest Loctite available on those tapers. In trying to get the gears off their tapers I broke two pulley pullers, without joy. I had to heat the gears to such an extent that I had to bin the oil seals afterwards.
One of the many mistakes in those first tandemtwins was that the oil seals ran not on the crankshafts, but on bushes on the gears. This allowed air to leak through the key slots in the tapers, causing all kinds of nasties.
Lessons learned: never use Loctite on tapers if you ever plan to take them apart again; just grind them with abrasive valve paste if they are not a perfect fit. And look for air leaks in even the most improbable places.

[peewee]

Keys don't hold on stuff, the taper does...... if it came off the nut was loose and or the taper was shagged. keys are only the locating device on flywheels.
lap it on, nut up tight, they stay there....... I learnt that lesson after I lost my flywheel a couple of times:bleh:

think of all the rubes that buy mx bikes. if there was no key they wouldnt a clue where to put the flywheel :killingme

[WilDun]

just grind them with abrasive valve paste if they are not a perfect fit.

I have seen some guys just putting coarse paste on the tapers and tightening them up - and it did seem to work! - animals?

[husaberg]

Question for the learned
If one was to be so silly as to do a air cooled 125 cylinder
Should the fins in the area of the outside of the transfers passages only attach to the transfers or to the rest of the cylinder as well?
I only ask as I note on nearly all water cooled cylinders the transfer have no outer water jacket.

[Flettner]

My 350 has fins all the way up from the crankcase.

http://i1056.photobucket.com/albums/t380/uniflow/IMG_4525_zps4b279c9c.jpg

[pete376403]

Is that one of those split-singles I read about?

[Frits Overmars]

If one was to be so silly as to do a air cooled 125 cylinder...If one was to be so silly as to do an air cooled cylinder of any capacity...
A friend of mine is that silly. Well, almost; he is competing in a class were stock frame and engine, stock intake system and stock cooling type are compulsory.
Should the fins in the area of the outside of the transfers passages only attach to the transfers or to the rest of the cylinder as well? I only ask as I note on nearly all water cooled cylinders the transfer have no outer water jacket.The outside of an air cooled cylinder gets so much hotter than a watercooler that you should put fins everywhere. And not just on the cylinder. This friend of mine added cooling fins under the engine, to the clutch cover, to the ignition cover, and even the last get surprisingly hot. O, and he won the championship.

[husaberg]

If one was to be so silly as to do an air cooled cylinder of any capacity...
A friend of mine is that silly. Well, almost; he is competing in a class were stock frame and engine, stock intake system and stock cooling type are compulsory.The outside of an air cooled cylinder gets so much hotter than a watercooler that you should put fins everywhere. And not just on the cylinder. This friend of mine added cooling fins under the engine, to the clutch cover, to the ignition cover, and even the last get surprisingly hot. O, and he won the championship.

Thanks Frits and Neil, So if I concede that the Germans know a little bit about air cooling.
Would this be the way to go.............

Or should I follow the route of the chainsaw and or scooter.
I ask about the chainsaw because they spend their life at max revs.

[Yow Ling]

Thanks Frits and Neil, So if I concede that the Germans know a little bit about air cooling.
Would this be the way to go.............

Or should I follow the route of the chainsaw and or scooter.
I ask about the chainsaw because they spend their life at max revs.

Just bite the bullet and get a RG bottom end,

[Flettner]

Is that one of those split-singles I read about?

Ha Ha very good.

[WilDun]

Thanks Frits and Neil, So if I concede that the Germans know a little bit about air cooling.
Would this be the way to go.............

Or should I follow the route of the chainsaw and or scooter.
I ask about the chainsaw because they spend their life at max revs.

This aircooling stuff is getting ridiculous - nearly as ridiculous as 14 speed gearboxes to compensate for the narrow power bands in the sixties!
Wouldn't it just be much easier for everyone to get together, change the rules and make aircooling illegal? :)

[F5 Dave]

The first Rotax tandemtwin engines (I received the first two in December 1980) had long tapers on the crankshafts and in the large primary coupling gears. In addition Rotax seemed to have used the strongest Loctite available on those tapers. In trying to get the gears off their tapers I broke two pulley pullers, without joy. I had to heat the gears to such an extent that I had to bin the oil seals afterwards.
One of the many mistakes in those first tandemtwins was that the oil seals ran not on the crankshafts, but on bushes on the gears. This allowed air to leak through the key slots in the tapers, causing all kinds of nasties.
Lessons learned: never use Loctite on tapers if you ever plan to take them apart again; just grind them with abrasive valve paste if they are not a perfect fit. And look for air leaks in even the most improbable places.
Maybe loctite master gasket rather than threadlock would be the go. Ya know that might explain a mates past issues with his 1980 256. Been reliable as last 20 years (in his spare bedroom).

Fine valve grinding paste is the go. I've had some coming on 30 years. Not like I'm going to be lapping any valves.

[Ocean1]

Thanks Frits and Neil, So if I concede that the Germans know a little bit about air cooling.

Mr Volkswagen knew more than is usually recognised.

Having read something of his work I'm surprised we haven't seen a lot more of ducted fan cooling in buckets...

[husaberg]

yeah I think the chainsaws and the scooters are onto it re the aircooling tech

[jasonu]

Wouldn't it just be much easier for everyone to get together, change the rules and make aircooling illegal? :)

If you are referring to Buckets then definitely not. Part of the attraction and beauty of the class are the different types and configuration of motors that fit within the rules and the lengths some builders go to to be competitive.

[Ocean1]

yeah I think the chainsaws and the scooters are onto it re the aircooling tech

One of the issues with fans is the problem with power going up exponentially with rev's. You don't need that much increase in airflow so the fan drive represents a loss up around max HP rev's.

The trick is to involve a torque limiting feature in the fan drive. Like a V belt that begins to slip over a certain torque.

[husaberg]

One of the issues with fans is the problem with power going up exponentially with rev's. You don't need that much increase in airflow so the fan drive represents a loss up around max HP rev's.

The trick is to involve a torque limiting feature in the fan drive. Like a V belt that begins to slip over a certain torque.

I am pretty sure the electro and viscous coupling fan on the mazda/ford couriers do that.....

http://www.youtube.com/watch?v=VxjfuJi4IUs

http://en.wikipedia.org/wiki/Electromagnetic_clutch

[WilDun]

Ducted fans soak up a lot of power and on a chainsaw it doesn't really matter but when trying to wring out a couple of horsepower on a bucket ......
I always thought (till now) that the original purpose of bucket racing was to keep things cheap and simple and give everyone a chance, but it's now gone way past that and we are into the realms of hi tech and expense.
Air cooling was used because all the little road bikes used for bucket racing were air cooled way back then, so these original barrels were kept on in the interest of simplicity in converting to a racer, but now, even that is obviously becoming increasingly more complicated to achieve comfortably than water cooling!
Ask anyone (who is able to manufacture a cylinder barrel) which is easier to do! - air or water cooled.
Guess all I'm saying is when you look at the lengths people will go to just to prove that it can be done, eg the posted photo of the bike - (think it might have been Frits who posted it) - the one with all those strange appendages sticking out of it. as opposed to a simple water jacket, radiator and tiny water pump which makes most sense?
- and no, I am actually very interested in all this experimental stuff, but an experimental design made simply to find a way past rules and restrictions? - no way!!
That just becomes a hobby on it's own, but I guess that's just how the (competitive) human brain works.:)

[Ocean1]

I am pretty sure the electro and viscous coupling fan on the mazda/ford couriers do that.....

Viscous clutches were common on a lot of American stuff, probably still are, but I don't think they were ever a particularly accurate torque control mechanism. I think most EM clutches are thermostatically switched, may be a useful secondary or control mechanism for a bucket but I'm not sure you'd want the fan kicking in just as you pulled out to pass that arsehole that'd been diligently blocking you for 5 laps coming onto the main straight.

I've seen two versions of flexible bladed fan, one where the cup on the blades simply flattened out as the pressure differential across them increased, which effectively produced a flatter flow curve, and another where centrifugal force did essentially the same thing, depowering the blades as rev's increased. I suspect either, or a mixture of both could map required air flow across the rev range quite accurately.

So could an electric fan with a variable speed drive, a few thermocouples and a basic PLC. A couple of standard bike radiator fans, one either side of the head/barrel and a bit of careful ducting might be enough.

[Ocean1]

- and no, I am actually very interested in all this experimental stuff, but an experimental design made simply to find a way past rules and restrictions? - no way!!

How many classes are there designed for technicians to excel, as opposed to riders?

[Yow Ling]

Viscous clutches were common on a lot of American stuff, probably still are, but I don't think they were ever a particularly accurate torque control mechanism. I think most EM clutches are thermostatically switched, may be a useful secondary or control mechanism for a bucket but I'm not sure you'd want the fan kicking in just as you pulled out to pass that arsehole that'd been diligently blocking you for 5 laps coming onto the main straight.

I've seen two versions of flexible bladed fan, one where the cup on the blades simply flattened out as the pressure differential across them increased, which effectively produced a flatter flow curve, and another where centrifugal force did essentially the same thing, depowering the blades as rev's increased. I suspect either, or a mixture of both could map required air flow across the rev range quite accurately.

So could an electric fan with a variable speed drive, a few thermocouples and a basic PLC. A couple of standard bike radiator fans, one either side of the head/barrel and a bit of careful ducting might be enough.

Strange really, a couple of the worlds authorities on small 2t engines categorically say , don't waste your time with air-cooled, thermally unstable blabla bla , the Aussies think they are a safety hazard , and you guys think by adding a fan you are going to come up with the next best thing. Its not like water cooled cylinders are made of gold or uranium or something rare.

[husaberg]

Strange really, a couple of the worlds authorities on small 2t engines categorically say , don't waste your time with air-cooled, thermally unstable blabla bla , the Aussies think they are a safety hazard , and you guys think by adding a fan you are going to come up with the next best thing. Its not like water cooled cylinders are made of gold or uranium or something rare.

I never said I was bright Mike...:lol:
20% leg up's in capacity are rare.........My own sudden interest in AC125's was from something Wob actually mentioned

[WilDun]

How many classes are there designed for technicians to excel, as opposed to riders?

Do you mean technicians or avid experimenters? I'm talking about the latter who are often self taught with maybe a trade background, but on the other hand there are the professionally trained people too like Dr. Gordon Blair etc. who made a huge contribution but didn't actually ever take part in the racing themselves.
The home experimenters are above being restricted by rules and regulations, classes etc. so long as they are working in their own environment, but sometimes they need to find someone to try out their creations on the track, I guess that's where they can become disillusioned ie. when they have to be hemmed in by restrictions and rules!
These are necessary of course. - Age old problem I guess and as you say, they don't have a class designed for them - but how can you design a class for pioneers?

This forum seems to work well without many restrictions, - sort of self moderates! :)

[Drew]

Viscous clutches were common on a lot of American stuff, probably still are, but I don't think they were ever a particularly accurate torque control mechanism. I think most EM clutches are thermostatically switched, may be a useful secondary or control mechanism for a bucket but I'm not sure you'd want the fan kicking in just as you pulled out to pass that arsehole that'd been diligently blocking you for 5 laps coming onto the main straight.

I've seen two versions of flexible bladed fan, one where the cup on the blades simply flattened out as the pressure differential across them increased, which effectively produced a flatter flow curve, and another where centrifugal force did essentially the same thing, depowering the blades as rev's increased. I suspect either, or a mixture of both could map required air flow across the rev range quite accurately.

So could an electric fan with a variable speed drive, a few thermocouples and a basic PLC. A couple of standard bike radiator fans, one either side of the head/barrel and a bit of careful ducting might be enough.
Fuck all that shit bro!

Lithium batteries weighing what they do, and electric motors driving the fans. Shit, in race terms that's free power!

[Yow Ling]

I never said I was bright Mike...:lol:
20% leg up's in capacity are rare.........My own sudden interest in AC125's was from something Wob actually mentioned

So it not just so you not need to destroke ?

[Drew]

So it not just so you not need to destroke ?
I figured that didn't get done much, do to the case volume not being that easy to reduce. Was I wrong?

[Ocean1]

Strange really, a couple of the worlds authorities on small 2t engines categorically say , don't waste your time with air-cooled, thermally unstable blabla bla , the Aussies think they are a safety hazard , and you guys think by adding a fan you are going to come up with the next best thing. Its not like water cooled cylinders are made of gold or uranium or something rare.

If I was going to waste some time it probably wouldn't be on a 125. I mean as much as I admire Smokey Unick's sentiment: "There's no substitute for cubic inches" he is demonstrably wrong. I was simply curious as to why the class seems to have ignored the whole fan cooled thing. If you're going to attempt to make a 25% capacity advantage work best it seems to me to be essential to minimise the disadvantage of the cooling system, no?

[husaberg]

So it not just so you not need to destroke ?

No (but it is part of the reason) I tried to find it Wob may not even know himself.......;)
if the new 107 rule goes through it is possible to do the 54.5. stroke by 50mm bore
Square would be better (I guess) under square does have a few pluses as well, according to some............

[Ocean1]

Fuck all that shit bro!

Lithium batteries weighing what they do, and electric motors driving the fans. Shit, in race terms that's free power!


It is. But it feels like cheating. And for the reason you've given I can't see stored energy remaining legal for long.

Besides, with less storage I could use regenerated brake energy to cool the engine.

In fact there's distinct possibilities in using a very large alternator and an even larger starter motor...

[TZ350]

One of the issues with fans is the problem with power going up exponentially with rev's. You don't need that much increase in airflow.

Electric fan, supplemented by natural air flow as the bike gets up to speed.


Lithium batteries weighing what they do, and electric motors driving the fans. Shit, in race terms that's free power!

Yep..... :D and they could be backed up by an on board generator, a generator does not draw any power from the engine until its required to produce current for the fan.


Could an electric fan with a variable speed drive, a few thermocouples and a basic PLC. A couple of standard bike radiator fans, one either side of the head/barrel and a bit of careful ducting might be enough.

Small DC motor speed control kits are cheap from Jaycar and you could use a range of thermal switches (also cheap) to turn the fan on and control its speed in switched steps.


Ducted fans soak up a lot of power.

True, but the power required can be pre stored in an accumulator.


I am actually very interested in all this experimental stuff, but an experimental design made simply to find a way past rules and restrictions? - no way!!

Making power makes heat, to make more power you have to get rid of more heat, finding ways past inherent restrictions is part of the challenge, if thats not your thing, then there is always the standard production classes like Super Bikes and F1, F2 etc.

I like riding my bike to see how the ideas work out but sometimes its nice to see how it could go with someone really good at riding on it.


Strange really, a couple of the worlds authorities on small 2t engines categorically say , don't waste your time with air-cooled, thermally unstable blabla bla,

World authorities say that about drinking and sin too, but it still has a fascination for me.


Its not like water cooled cylinders are made of gold or uranium or something rare.

But they are only a 100cc and this is a game where size can matter.

297710



destroke ?
I figured that didn't get done much, due to the case volume not being that easy to reduce.

As the crankcase volume is a great place to store fresh mixture before its sucked up into the cylinder by the wave action of the pipe, the relative increase in volume by de stroking a 125-150 to a 100 could be beneficial.

[WilDun]

finding ways past inherent restrictions is part of the challenge, if thats not your thing, then there is always the standard production classes like Super Bikes and F1, F2 etc.

I like riding my bike to see how the ideas work out but sometimes its nice to see how it could go with someone really good at riding on it.

World authorities say that about drinking and sin too, but it still has a fascination for me.




I don't think I'll be riding any bike in the foreseeable future unless miracles do happen :no:

Like I said humans often do things more for the challenge than for any practical reason and taking on that challenge really becomes the actual hobby, but that's ok.

Sin is probably a bit of a bitch to define - much like the restrictions we get imposed over fuels etc.etc. - nobody can decide exactly what should or what shouldn't be done and the fascination is really only to see how far we can go!

[husaberg]

I figured that didn't get done much, do to the case volume not being that easy to reduce. Was I wrong?




As the crankcase volume is a great place to store fresh mixture before its sucked up into the cylinder by the wave action of the pipe, the relative increase in volume by de stroking a 125-150 to a 100 could be beneficial.

http://2.bp.blogspot.com/-PDV0HxmX6a4/T2J46M5ShII/AAAAAAAAAVI/8y7IoDstdxc/s1600/kateupton1-mjday.jpg

[TZ350]

Like I said humans often do things more for the challenge than for any practical reason and taking on that challenge really becomes the actual hobby, but that's ok.

Yes, True, ... I started out trying to build a bike/engine that I could win races with, now its about trying to build a bike/engine that could win races, there is a big difference.

[Frits Overmars]

... an experimental design made simply to find a way past rules and restrictions? - no way!!Let me rephrase that for you: a design made to stay within rules and restrictions.


How many classes are there designed for technicians to excel, as opposed to riders?Not enough. And they are getting ever scarcer, even in Grands Prix. In Moto2 you are not even allowed to correct the shortcomings in the mandatory Honda engines.

[husaberg]

I have a fun fact from the thirties Velocette ran a number of tests with a KTT350 (which was their OHC factory racer of the time)
they ran there std straight exhaust with a megaphone curved front pipe rear exit.
Then they replicated the test with the same bike with a totally straight exhaust and magaphone of the exact dimensions and gained 1.5 hp extra... food for thought.

What would be your take Frits and Wob on a 50mm x54.5mm

[WilDun]

Let me rephrase that for you: a design made to stay within rules and restrictions.

Not enough. And they are getting ever scarcer, even in Grands Prix. In Moto2 you are not even allowed to correct the shortcomings in the mandatory Honda engines.

To the first answer
I was just thinking out loud and to me, a true experimenter will not be fazed by rules, probably because he knows that he won't learn anything by doing that, or because he does it for his own satisfaction, probably just to put his thoughts into something tangible, not to win races.
However if he wants to compete with others then he has to do what those "up there" people say he must do.

I think that "TZ" nailed it when he said that, "a bike that I could win races with, now its about trying to build a bike/engine that could win races, there is a big difference" - so the bike that "could win races' places his efforts firmly inside the square, that's how most people are and that's fine......but there are those people in the world who will try bending the rules just for the hell of it and others who will passionately believe that their way is best, a better way to do it and want a chance to prove it.

These "free spirits"are very often the people who resent the big companies becoming dictators and force the general public down their "preferred road". (as has already happened with the two stroke in most countries).
I felt you might have been implying that when you mentioned Moto 2 grands prix..

BTW, how did it come about that Moto 2 all use Honda engines ? - guess it's the same as the tyre scenario? - why not the other classes?

[Frits Overmars]

to me, a true experimenter will not be fazed by rules, probably because he knows that he won't learn anything by doing thatHe may not learn what he wished to learn, but learn he will.

there are those people in the world who will try bending the rules just for the hell of itIf the rules are solid they can't be bent. If there are loopholes, you're mad if you don't use them.
I've spent half my life exploring loopholes (and still am); now I also write rulebooks :D.

These "free spirits"are very often the people who resent the big companies becoming dictators and force the general public down their "preferred road". (as has already happened with the two stroke in most countries).I felt you might have been implying that when you mentioned Moto 2 grands prix.I plead guilty.

how did it come about that Moto 2 all use Honda engines ?A despicable deal between Honda and Dorna; a devaluation of Grand Prix motorsport in my opinion.

[Frits Overmars]

What would be your take Frits and Wob on a 50mm x54.5mmIt might work. A long-stroke two-stroke will have better time.areas than a short-stroker. And as an added benefit you may find suitable pistons in the kart world.

[wobbly]

I think a 50 by 54.5 would be just fine at 107cc for whatever class you are looking at.
Its easy enough to get good 50mm pistons and 110 to 120 rods to go on the crank and as long as its designed to be run "as it should " by spinning
to 14,000 all day as we know that stroke can handle , then a very fast motor would be easy to design, as well as build.
Weld an alloy liner into what was originally a 54 bore I take it, then plate it.

[Flettner]

A despicable deal between Honda and Dorna; a devaluation of Grand Prix motorsport in my opinion.

Totaly agree, they have ruined GP motorsport.

[Drew]

It is. But it feels like cheating. And for the reason you've given I can't see stored energy remaining legal for long.

Besides, with less storage I could use regenerated brake energy to cool the engine.

In fact there's distinct possibilities in using a very large alternator and an even larger starter motor...

Stored energy has been a part of racing since the year dot. Total loss ignition is very common.

Cheating? Don't see it that way, but I get your drift.

Big gennie, and starter are probably big weight. My 21amp Shorai is 400grams I think.

[Ocean1]

Stored energy has been a part of racing since the year dot. Total loss ignition is very common.

Cheating? Don't see it that way, but I get your drift.

Big gennie, and starter are probably big weight. My 21amp Shorai is 400grams I think.

But less weight than, say another 20hp engine, legal, and getting lighter every year as motor and battery tech rapidly evolves. And for how much time is that existing engine on full throttle anyway?

See, with probably somewhere around 20kg worth of kit you could run that one engine at full throttle 100% of the time, charging a battery when you don't need that much and then, when you do want power....

It gets better. An engine that can be tuned for a static 12krpm can make more hp than one that has to have power across 30% of its rev range. So a nominal 35hp engine running at peak hp rpm full time, charging a battery for, say 30% of that time can provide maybe 50hp during those times when you want it. And a 50hp bucket is nothing to sneeze at.

[pete376403]

If the engine is just to power a generator, and the electric motor is actually turning the wheels, does this mean the bike has two motors? Is that allowed?
Tyrell, because they were stuck with naturally aspirated engines, tried to get turbos banned in F1 by claiming the two engine thing, one being the petrol powered engine driving the wheels and the other a gas turbine powering a supercharger compressor. They were not successful in their claim.

[Ocean1]

If the engine is just to power a generator, and the electric motor is actually turning the wheels, does this mean the bike has two motors? Is that allowed?
Tyrell, because they were stuck with naturally aspirated engines, tried to get turbos banned in F1 by claiming the two engine thing, one being the petrol powered engine driving the wheels and the other a gas turbine powering a supercharger compressor. They were not successful in their claim.

A generator/motor used like that is considered just a transmission in most heavy industry. Until you stick a battery in the system that's really all it is.

F1 regenerative systems are politically tenable simply because they're environmentally shiny, but I'm pretty sure that if someone makes them work too well there'll be heated discussions about cheque book racing...

[Drew]

There's nothing in the rules about electric bikes. One could be made to destroy everything burning fossil fuel, with their current cc limits.

Can even put Mark's regen under brakes idea to effect pretty easily.

[koba]

Wobbly, when you talk of pipe length, is it total length, or to the baffle mid point?

[Frits Overmars]

...I could use regenerated brake energy to cool the engine. In fact there's distinct possibilities in using a very large alternator and an even larger starter motor...About 100% of brake energy is generated at the front wheel. How would you recover that? An in-wheel generator would be fine if only it had zero mass...

...for how much time is that existing engine on full throttle anyway? See, with probably somewhere around 20kg worth of kit you could run that one engine at full throttle 100% of the time, charging a battery when you don't need that much and then, when you do want power....True.
It gets better. An engine that can be tuned for a static 12krpm can make more hp than one that has to have power across 30% of its rev range.Not true. You could drop items like power valves and power jets, but that won't raise peak power. And you can't gain anything in changing exhaust pipe dimensions; they are already optimal for peak power.
So a nominal 35hp engine running at peak hp rpm full time, charging a battery for, say 30% of that time can provide maybe 50hp during those times when you want it.Aside from your assumed power figures, that is true. Still, too bad that we haven't yet found a way of recovering that front wheel brake energy.
A generator/motor used like that is considered just a transmission in most heavy industry. Until you stick a battery in the system that's really all it is.True again. And in my opinion, if that battery is empty at the start of the race, this setup should still be considered just a combustion engine with an electric CVT.
It could even be more than just a transmission: you wouldn't need a clutch anymore, implementing traction control would become much simpler and you could have a reverse gear if you wish.
Electric motors already have an excellent efficiency and I have been searching for a generator with an efficiency to match. That would definitely be the answer to all my transmission wishes.
And I may have found what I've been looking for: http://www.magnomatics.com .

[Ocean1]

About 100% of brake energy is generated at the front wheel. How would you recover that? An in-wheel generator would be fine if only it had zero mass...

I wasn't really offering. :laugh: But getting some sort of drive, possibly hydraulic, back from the front wheel to a generator midships would be a start. Hydraulics aren't spectacularly efficient, but recovering say 80% of that energy is probably worth at least the 3-4 kg worth of pump/motor. If you can use it.


Not true. You could drop items like power valves and power jets, but that won't raise peak power. And you can't gain anything in changing exhaust pipe dimensions; they are already optimal for peak power

OK. I'd sort of assumed a few % could be got at peak by ignoring the requirement for flexibility, but the advantages of a full-time 100% output available at need doesn't rely on that few extra %.


Aside from your assumed power figures, that is true.

I was simply interpolating current best practice, re-tuned for static revs. If we have to live with 32hp odd then, as above, let's have it there all of the time, eh?


True again. And in my opinion, if that battery is empty at the start of the race, this setup should still be considered just a combustion engine with an electric CVT.
It could even be more than just a transmission: you wouldn't need a clutch anymore, implementing traction control would become much simpler and you could have a reverse gear if you wish.
Electric motors already have an excellent efficiency and I have been searching for a generator with an efficiency to match. That would definitely be the answer to all my transmission wishes.
And I may have found what I've been looking for: http://www.magnomatics.com .

One of the other good things about such a setup might be the accuracy with which a small processor could manage generation and consumption. Even learning which parts of a track to anticipate load requirements.

Generators are well outside my field, unfortunately, will have a wee look at your discovery though...

Edit: I see: "Magnomatics ultra high torque PDD® operates with a conventional off-the-shelf AC electric drive"
Is that what you had in mind? Some of those AC drives come with some quite advanced intelligence these days.

I can see huge advantages in a rim-mounted drive/generation system, simply because of the high velocity and low torque. No drive load through the wheel hub. Same rationale for the front wheel generator... In fact if the componentry is there anyway you'd be braking on the front and driving on both wouldn't you? Or is that superbike territory.

[Ocean1]

Can even put Mark's regen under brakes idea to effect pretty easily.

I get SO tired of having all of these brilliant ideas just to find someone else had them decades ago, y'know?

But don't expect the rules to favour technology not available on the showroom floor for long, dude.

[Frits Overmars]

getting some sort of drive, possibly hydraulic, back from the front wheel to a generator midships would be a start. Hydraulics aren't spectacularly efficient, but recovering say 80% of that energy is probably worth at least the 3-4 kg worth of pump/motor. If you can use it.I'm afraid those hydraulics would yield less then 80% efficiency and weigh more than 4 kg. And even a few kilos of extra unsprung weight is very bad for lap times.

I can see huge advantages in a rim-mounted drive/generation system, simply because of the high velocity and low torque. No drive load through the wheel hub. Same rationale for the front wheel generator... In fact if the componentry is there anyway you'd be braking on the front and driving on both wouldn't you? Or is that superbike territory.I can see the same advantages but I'm afraid the rim would get too heavy and too hot. If anyone would offer a solution for those problems, I would jump at it.
Two wheel drive sounds great if you're ploughing through mud, but agricultural racing is not my hobby. And superbikes spend a lot of their time on one wheel, so no advantage there either.

[Frits Overmars]

I get SO tired of having all of these brilliant ideas just to find someone else had them decades ago, y'know?The main thing is to find them at all.
BTW, I love brainstorming like this.

[136kg136ps]

Frits,could the energy be transferred via something similar to a speedo cable to a regenerative device more central to the motor?Perhaps even coupled to the motor in a manner so it could operate in braking as a generator and on acceleration as a motor,the additional rotating/sprung mass would be less than having all that on the wheel and fork.You would get energy from the front braking and perhaps have some engine braking as well.Of course it would take a very complex control system.

[Frits Overmars]

Frits,could the energy be transferred via something similar to a speedo cable to a regenerative device more central to the motor?Perhaps even coupled to the motor in a manner so it could operate in braking as a generator and on acceleration as a motor,the additional rotating/sprung mass would be less than having all that on the wheel and fork.You would get energy from the front braking and perhaps have some engine braking as well. Of course it would take a very complex control system.That is a very logical line of thought. Can we find a 30 BHP speedo cable?
Even if we could, it wouldn't do us much good because braking power, even in a bucket, can easily exceed 100 BHP. And all that power through that cable, or chain, or cardan shaft or whatever, should not influence the sensitivity of the steering in any way. I don't yet see a practical solution.

[husaberg]

That is a very logical line of thought. Can we find a 30 BHP speedo cable?
Even if we could, it wouldn't do us much good because braking power, even in a bucket, can easily exceed 100 BHP. And all that power through that cable, or chain, or cardan shaft or whatever, should not influence the sensitivity of the steering in any way. I don't yet see a practical solution.

brakes turn motion into heat, engines turn chemical composition into heat and energy.
i thought oh yeah....thermocouples...unfortunalty thermocouples all though they can generate electricty from heat, they are only about 5% effeicent
Then again how efficent is an internal combustion engine 10%.......
(the kergs or what ever it is called system) seems to work like a kids toy.. remember the ones where you used to load in flywheel motion and then hit the button and then relase this stored energy and off they went.
big issue would be the gyro effect would render the bike handling "interesting" to say the least, it could be worked around with say two of them contra rotating i guess?


In the 1950s, flywheel-powered buses, known as gyrobuses, were used in Yverdon, Switzerland and there is ongoing research to make flywheel systems that are smaller, lighter, cheaper and have a greater capacity. It is hoped that flywheel systems can replace conventional chemical batteries for mobile applications, such as for electric vehicles. Proposed flywheel systems would eliminate many of the disadvantages of existing battery power systems, such as low capacity, long charge times, heavy weight and short usable lifetimes. Flywheels may have been used in the experimental Chrysler Patriot, though that has been disputed.[16]

Flywheels have also been proposed for use in continuously variable transmissions. Punch Powertrain is currently working on such a device.[17]

During the 1990s, Rosen Motors developed a gas turbine powered series hybrid automotive powertrain using a 55,000 rpm flywheel to provide bursts of acceleration which the small gas turbine engine could not provide. The flywheel also stored energy through regenerative braking. The flywheel was composed of a titanium hub with a carbon fiber cylinder and was gimbal-mounted to minimize adverse gyroscopic effects on vehicle handling. The prototype vehicle was successfully road tested in 1997 but was never mass-produced.[18]

In 2013, Volvo announced a flywheel system fitted to the rear axle of its S60 sedan. Braking action spins the flywheel at up to 60,000 rpm and stops the front-mounted engine. Flywheel energy is applied via a special transmission to partially or completely power the vehicle. The 20 centimetres (7.9 in), 6 kilograms (13 lb) carbon fiber flywheel spins in a vacuum to eliminate friction. When partnered with a four-cylinder engine, it offers up to a 25 percent reduction in fuel consumption versus a comparably performing turbo six-cylinder, providing an 80 hp boost and allowing it to reach 100 kilometres per hour (62 mph) in 5.5 seconds. The company did not announce specific plans to include the technology in its product line.


another way of looking at it is If the heat could be captured The heat could be turned into steam ...but thats only a pipe dream:lol:
i do remeber a ducati was twin converted to a single and the spare cylinder was used as a pump supercharger,it charged a pressure vessle and this was used as boost available on demand. It weighed the same as a twin likely cost the same to mass produced made pretty much the same hp as a twin so was pointless unless it was a cc or one cylinder class.

[Flettner]

Just become massless then you don't need brakes for the corner.

[2T Institute]

Porsche KERS system is a carbon fibre rotor with the magnets embedded in it mounted paralel with the ground, most bang for buck that way. Besides buckets are about finding how little you need the brakes and all about going faster through the corner

[Ocean1]

I'm afraid those hydraulics would yield less then 80% efficiency and weigh more than 4 kg. And even a few kilos of extra unsprung weight is very bad for lap times.

Pump/Motor at the hub could be as light as a simple twin gear device, need weigh no more than, say a brake caliper. Brake control might be via a swash-plate pump/motor at the other end of the circuit. Hoses might weigh no more than a disc. Admittedly a 6mm hose running reasonably high pressure is fairly stiff, likely to affect suspension performance, but probably only twice as stiff as a standard brake hose under the same conditions. As for efficiency, both gear pumps and swash plate pumps are typically around 90% mechanically efficient, so 75% overall plus other minor system losses isn't outrageously overstating it. And we are talking about energy usually totally lost, the ability to recover and use it at anything better than the original bike's power to weight ratio is likely to be worth considering.


I can see the same advantages but I'm afraid the rim would get too heavy and too hot. If anyone would offer a solution for those problems, I would jump at it.


Doesn't actually have to BE the rim, could be a ring fastened to and insulated from the rim.

You got me on the weight, though, even counting the mass saved from eliminating the existing brake system it's likely to be heavier. How much heavier? I don't have the time or tallent to specify those magnets, but neodymium is the material of choice for hybrid vehicles, I just don't know how much is chosen.

I sometimes have occasion to use these: http://www.linmot.com/ I wonder if we could convince them to make a 400mm ring shaped "rotor" and a curved stator...

[F5 Dave]

Just become massless then you don't need brakes for the corner.

yeah, but think of the crashes after lunchbreak.

[Flettner]

The 360 rotary valve engine, vairable rotary valve housing. The intake side is not machined yet but it's a start. This engine will have the throttle controled by the ECU, it will adjust the valve housing, this will become the throttle. I will just tell the ECU how much torque I need and it will deliver.
Imagine the crashes after lunchbreak on this one!

http://i1056.photobucket.com/albums/t380/uniflow/IMG_4943_zps7b97d410.jpg

http://i1056.photobucket.com/albums/t380/uniflow/IMG_4944_zpsf0934658.jpg

http://i1056.photobucket.com/albums/t380/uniflow/IMG_4948_zps97cb7957.jpg

http://i1056.photobucket.com/albums/t380/uniflow/IMG_4941_zps317307c5.jpg

[F5 Dave]

with so many projects on the go it would be only fair if the universe grants you a lifetime extension.

[Flettner]

Unfortunatly I like projects.

[Muciek]

http://www.ronax500.com/en/index.php

160HP and 145kg's not bad but could be better :D

[WilDun]

If I'm really honest, all I'm fit for these days is to sit, look in occasionally and comment (you guys don't mind do you?) :mellow:

What I was trying to say earlier was, give all these guys a fair go with experimental projects which may or may not fit in with the bucket "rules" but which make sense to at least try.
No need to have a championship or even to win races, the only competition being the fight against convention with it's rigid guidelines stifling enterprise! -maybe something quite revolutionary evolving either by continuous tinkering or building on each others designs.

It would appear from the last few posts that there are a few enterprising guys here just dying to try things they've thought up, but really having no track time at all because their designs wouldn't be compatible with the rulebook.
Much of what has been suggested won't work of course, but a great way to give keen inventors to airy fairy hopefuls a chance to try things. Dyno's are fine but there's a lot of other stuff which can only be sorted on the track, often in racing conditions with the possibility of some nasty results, guess you could say that's possible with regenerative braking which is at present an unknown!
Of course, safety would still be paramount at all times.
Is there any provision for them or their riders to have time on the tarseal now and again for experimentation? - I imagine there's probably no such problem with the off road stuff.

Then again, I could quite possibly be wrong! and this scheme might not work! :msn-wink:

[Frits Overmars]

...the kergs or what ever it is called system seems to work like a kids toy.. remember the ones where you used to load in flywheel motion and then hit the button and then relase this stored energy and off they went.
big issue would be the gyro effect would render the bike handling "interesting" to say the least, it could be worked around with say two of them contra rotating i guess?KERS (Kinetic Energy Recovery System) is fine for F1 cars with 20 mm of suspension movement and no body roll at all. The gyroscopic forces would tear the flywheels out of the cars if they would start rolling into corners as we bikers do.
Two contrarotating flywheels will cancel out some of the gyroscopic torque but that would only mean their axes would refuse to be moved at all.


yeah, but think of the crashes after lunchbreak.You are clearly thinking outside the (lunch)box :niceone:

[chrisc]

Hi all. I'm on holiday in Spain and it's making me so happy seeing all the motorcycles around. Plenty of rowdy two smokes in the streets too. Loving it. I wonder if I can carry on an engine on the way home.

[TZ350]

What I was trying to say earlier was, give all these guys a fair go with experimental projects which may or may not fit in with the bucket "rules" but which make sense to at least try. The only competition being the fight against convention with it's rigid guidelines stifling enterprise!

It would appear from the last few posts that there are a few enterprising guys here just dying to try things they've thought up, but really having no track time at all because their designs wouldn't be compatible with the rulebook. Is there any provision for them or their riders to have time on the tarseal now and again for experimentation?

Speedpros H2o (to be turbocharged/supercharged) EFI 125 is one bike I am aware of that currently is not compatible with the rule book and it has enjoyed as much track time as he has wanted for testing his ideas, so it happens.

And its no secret as all progress has been posted on the #6 and Ecotrons EFI threads.

The only requirement for the enterprising, is to stop talking and start working.

[Grumph]

Hi all. I'm on holiday in Spain and it's making me so happy seeing all the motorcycles around. Plenty of rowdy two smokes in the streets too. Loving it. I wonder if I can carry on an engine on the way home.

John Boote got a TZ750 into 5 suitcases......

[WilDun]

And its no secret as all progress has been posted on the #6 and Ecotrons EFI threads.

The only requirement for the other enterprising guys, is to stop talking and start working.

Ha ha - Ok I got it wrong! - I won't be doing much work of course, but I'll go and do some more reading on the threads you mention and I'll be checking out your (legal) porcupine when it appears on the track.:mellow:

[speedpro]

Speedpros H2o (to be turbocharged/supercharged) EFI 125 is one bike I am aware of that currently is not compatible with the rule book and it has enjoyed as much track time as he has wanted for testing his ideas, so it happens.

And its no secret as all progress has been posted on the #6 and Ecotrons EFI threads.

As it is the bike is completely legal.

Once the turbo is put on it will of course suddnely become a 100cc bike :whistle:

I'm about to get back into working on that bike. We bought a new house and it's taken a bit to get things sorted but nearly there. Need to build a new bench for the drill press grinder and vice and we'll be pretty well done.

[TZ350]

Ha ha - Ok I got it wrong! -

After reading Speedpros post, looks like I got it sort of wrong too...... ahh well ... :spanking:

[F5 Dave]

http://www.ronax500.com/en/index.php

160HP and 145kg's not bad but could be better :D
Yeah just plank your 30 advance of 100k euro down and wait 6months min and then another 20k to hire a hit on the directors if you can find them. If I was insanely rich I'd risk it anyway. But I'd hire the hit in advance on a post dated cheque in case I forgot.

[F5 Dave]

Hi all. I'm on holiday in Spain and it's making me so happy seeing all the motorcycles around. Plenty of rowdy two smokes in the streets too. Loving it. I wonder if I can carry on an engine on the way home.
If you could just pop along to the Derbi factory museum in a long overcoat. See if you can bring me back Youichi's bike. Probably only be 2suitcases worth.

[Sketchy_Racer]

As it is the bike is completely legal.

Once the turbo is put on it will of course suddnely become a 100cc bike :whistle:

I'm about to get back into working on that bike. We bought a new house and it's taken a bit to get things sorted but nearly there. Need to build a new bench for the drill press grinder and vice and we'll be pretty well done.

I'm looking forward to seeing yours go with a turbo! Have you got a RHB31?

[speedpro]

yeah, RHB31. The manifolds are more or less made and just need a few more bits glued together. The intake is actually finished & fitted and is possibly acting as a bit of a restriction unturbo'd. Need oil lines yet but saved a website selling them at a good price - http://www.kemotorsport.com/

[quallman1234]

yeah, RHB31. The manifolds are more or less made and just need a few more bits glued together. The intake is actually finished & fitted and is possibly acting as a bit of a restriction unturbo'd. Need oil lines yet but saved a website selling them at a good price - http://www.kemotorsport.com/

Thats who we got the AMR300 off.

[WilDun]

After reading Speedpros post, looks like I got it sort of wrong too...... ahh well ... :spanking:

Having reviewed all my statements, I have decided stay out of all the politics and stick to the stuff I actually can do, ie. until I know exactly what I'm talking about !:Oops:

[peewee]

hey guys you ever noticed on a cylinder reedvalver theres usually quit a bit of extra space on top,below and behind the reed cage ( in the area where the reed screws set when the block is mounted in the cylinder). im sure someones tried filling in some of this area with epoxy. anything to be gained from it ??

[Drew]

hey guys you ever noticed on a cylinder reedvalver theres usually quit a bit of extra space on top,below and behind the reed cage ( in the area where the reed screws set when the block is mounted in the cylinder). im sure someones tried filling in some of this area with epoxy. anything to be gained from it ??Ooooooohhhhhh, this one applies to one of my motors....I wait with no patience at all...:eek5:

[koba]

It's pretty tight once you bolt it altogether on most I've seen.
I've kept as little volume as possible when working in this area, seems logical.

[Drew]

It's pretty tight once you bolt it altogether on most I've seen.
I've kept as little volume as possible when working in this area, seems logical.Soooo, some blue-tac to see what sorta volume we're talking about when it's assembled, and then repeat with glad wrap and devcon if it's quite a lot?

[wobbly]

Again this is the old story of trying to put specifics onto a huge generality.
The reed cavity of course is connected to the case, and it depends entirely what the total volume is,as to the advisability of
filling in the so called dead areas.

I have found that unlike a full noise rotary valve engine there seems to be no power increase if the case volume is made bigger than a 1.3 ratio when using reeds
be they direct into the case or cylinder mounted.
And another generality seems to be that the crappyer the transfer ducts, the ratio should tend the other way toward a smaller 1.4 ratio.

If the case was too small to start with and you fill the reed cavity dead areas, this will make it worse, and vise versa, but as all the factories are now tending toward making the reed box
smaller and smaller it would seem that filling the cavities and also filling the volume in front of the reed ( to the point where you would think the flow would for sure be affected badly )
then I would say its a good thing AS LONG AS YOU ARE MEASURING AND CORRECTING THE TOTAL CASE VOLUME.

[koba]

Soooo, some blue-tac to see what sorta volume we're talking about when it's assembled, and then repeat with glad wrap and devcon if it's quite a lot?

Sounds like a plan!

My MB one is all part of a home made adaptor, tight enough to need screws with smaller heads, had to grind it out to fit thicker reeds!

Still, I'm no expert...

[koba]

Again this is the old story of trying to put specifics onto a huge generality.
The reed cavity of course is connected to the case, and it depends entirely what the total volume is,as to the advisability of
filling in the so called dead areas.

I have found that unlike a full noise rotary valve engine there seems to be no power increase if the case volume is made bigger than a 1.3 ratio when using reeds
be they direct into the case or cylinder mounted.
And another generality seems to be that the crappyer the transfer ducts, the ratio should tend the other way toward a smaller 1.4 ratio.

If the case was too small to start with and you fill the reed cavity dead areas, this will make it worse, and vise versa, but as all the factories are now tending toward making the reed box
smaller and smaller it would seem that filling the cavities and also filling the volume in front of the reed ( to the point where you would think the flow would for sure be affected badly )
then I would say its a good thing AS LONG AS YOU ARE MEASURING AND CORRECTING THE TOTAL CASE VOLUME.

Interesting.

I'm soon going to revisit all my measurements, I think I have underestimated the effect of a wee grind here, a little bit off there...

[Drew]

Interesting.

I'm soon going to revisit all my measurements, I think I have underestimated the effect of a wee grind here, a little bit off there...Isn't Wob saying that wouldn't really matter fuck all?

Re the 'dead' area though, does it matter? Why wouldn't the flow just treat it like a wall and sail right on by?...






considers putting blue-tac away, but likes squishing it around

[koba]

Isn't Wob saying that wouldn't really matter fuck all?

Re the 'dead' area though, does it matter? Why wouldn't the flow just treat it like a wall and sail right on by?...


considers putting blue-tac away, but likes squishing it around


S'bout volume and resonance a fair bit too, right?

[koba]

Wob, does it matter a shit? I just made mine tight as it seemed logical to keep minimal section changes in the inlet tract, as out of the way as it is...

[jonny quest]

Can someone provide the name of the electrical trigger box that's found somewhere in these 950 pages please? I've been looking for an hour and I didn't bookmark that page when I first ran across it.

I'm looking for a electrical device to shut off a electronic powerjet after a certain RPM, seeing as my CDI box doesn't have this capability

[husaberg]

Can someone provide the name of the electrical trigger box that's found somewhere in these 950 pages please? I've been looking for an hour and I didn't bookmark that page when I first ran across it.

I'm looking for a electrical device to shut off a electronic powerjet after a certain RPM, seeing as my CDI box doesn't have this capability

ignitech............

[speedpro]

For the area behind the reed stops, if fitted, it isn't going to make any difference to the flow, only to the volume of the cases. I've been very careful keeping the inlet tract as constant a cross section as I can manage. From where the tips of the reeds are at full open I've tried to keep the duct the same size as far as possible. It looks restrictive sometimes but I keep trusting that it's right. Same between the carb and reeds. Especially with a splitter and a bunch of devcon it can look quite restricted when the reeds are fitted and closed. With the reeds removed though it looks like a jet engine intake each side of the splitter and I can see how the air would flow nicely. Back to back tests with standard (old) Yamaha reeds on the dyno yielded good gains plus I could clearly hear a difference to the sound of the intake.

A thought I've had is that having solid reed stops or the equivalent built into the reed cavity, could actually impede the reed action, as the air trapped behind the reed as it reaches full open could slow the reed down as the air is squeezed out, or it could act like a spring and bounce the reed closed, or if the reed manages to get fully open against the stop it might hesitate to close as air struggled to return behind the reed as it starts to close. Or that effect might actually be a benefit. Friggin 2 strokes, who knows.

[wobbly]

EVERYTHING makes a difference in these fekin things, dont assume ANYTHING.
I have been wanting to try reed spacers on a KZ2 kart engine for ages, having spotted one on the grid fitted to the enemy's engine.
So prior to the Nationals at Easter I finally got our good TM onto the dyno to recheck the performance with a new "high inertia" crank.
The crank replaced the so called " factory special tune " version that costs some E600 from TM for a KZ10.
I got hold of the wheels for an old KZ9 that were very simple in that they are plain disks with only 1 piece of Mallory opposite the pin for balance - nothing else.
So I added two 19mm by 19mm Mallory slugs in each wheel, on centreline so the balance isnt affected, only the rotating inertia.
Short story is this mod lost 1 Hp all the way to 13200 where it crossed just under peak Hp - high inertia = harder to spin up ( I think )
After peak Hp the lines diverged, and at 14500 the thing made 6Hp more,up from 35 to 41, with a much smoother roll-off ie no " fall of the cliff " effect.
This enabled at least a 1/2 tooth to be added at the rear, well off setting the 1Hp loss with way faster off corner acceleration due to gearing torque multiplication.
I added a 5mm reed spacer and this lost around 2Hp below 11,000,gained 2 Hp between 11,000 and peak, then lost that 2 Hp and more after, getting progressively worse.
So I started playing with reed and backup tensions,using softer main petals I got back the loss under 11,000 and with wider/stiffer backups,spaced further away from the mains
I got back nearly all the overv loss.
So of course I then took the spacer out to recheck, and it made even more power everywhere,fucked if I know,enough to drive you up the wall - but hey it took the National title so who's complaining now.

[koba]

Yeah, I'm going slowly mad thinking about mine, have the ignitch pulgged in now, unable to improve on a straight 15 degrees all the way through.

I'm sure I could spice it up in the mid range and improve response more, main thing im looking for is over-rev though as that will net me the best return on the track.

I'd be convinced it is the pipe, but I've had more revs on the same one before, too much has changed to be sure but it may be the head.
I wish I had the resources to test each change properly, but I know that would likely lead to more questions and more madness.

[peewee]

the intention certainly wasnt to reduce case volume but its innevitably one of the side affects i guess. the reasoning was to reduce voids in the reed area that contribute to nothing. thats assuming the voids have no value but i dont know for sure. i thought about filling in some of the extra space above and below the reed stoppers also. if nothing else, atleast the reed screws wont ever fall into the engine :2thumbsup. anyways heres where im at now

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20140607_124058_zpse4f80d9c.jpg
http://i1081.photobucket.com/albums/j357/doddledo/IMG_20140612_171902_zps69099217.jpg

[ken seeber]

KERS for bikes

If we consider a 125 (2 stroke, of course !!) road racer weighing 140 kg all up undergoing maximum braking. Assuming that it might be travelling at 100 km/hr at this time and that it was de-accelerating at 1.4 g (an estimate) and all the braking was being performed by the front wheel only, then the tractive force being exerted by the front tire against the road surface can be calculated from:

Force = ma = 140 * 9.8 * 1.4 = 1920 newtons, or more understandably 196 Kg

At 100 km/hr, the actual braking power being dissipated by the front brake can be calculated from:

Power (kW) = F (newtons) * velocity (met/sec)

= 1920 * (100 * 1000/(60 *60)/1000

= 53 kW (= 71 hp). At 200 km/hr, this would be doubled.

At 100 km/hr, the wheel (assume 600 in diameter) would be rotating at:

= (100 *1000/60)/(pi * 0.6) = 884 rpm.

So, with all that in mind, let’s consider the additional following:

1. Any energy recovery from the back wheel is not available, as pointed out by Frits
2. Going back in time as kids on our pushies, we used to have lights that were powered by a small friction driven generator that was flicked across on to the side of the front tire and driven with a small serrated roller on the end of the generator. Crude & inefficient I am sure, but it did work.
3. Attached is a picture of a 6000 rpm 20 kW electric motor, weighing just over 4 kg. This has an outside diameter of around 110 mm. In this case, the actual body of the motor actually (& usefully) spins.
4. That any energy recovered during braking and can be returned to provide some motive force must be considered useful, assuming that any gains are not offset by any losses due to the extra weight, complication, cost etc
5. It would be very undesirable to add mass (eg, 4 – 5 kg) to the unsprung mass to the front wheel assembly

So, combining these technologies, we could have the outside diameter of the motor rubbing/rolling against the outside diameter of the tyre. See attached sketch. The electric motor/generator in this is shown to be mounted on an arm that is suspended from the frame near the steering head. Alternatively it could be suspended from the lower triple clamp (so that it rotates with the total steering assembly). The motor in this position would not add to the unsprung mass, but being at approx 90 degrees to the wheel centre it wouldn’t be to so sensitive to wheel up & down movement. At 100 km/hr it would be spinning at 4820 rpm, within its 6000 rpm range

Obviously it would require some means of actuating to apply pressure against the tire whilst braking (& accelerating). In absorption mode, it might only be taking a quarter or so of the total braking power required, so it wouldn’t dominate the overall braking feel.

So, we have taken this percentage of braking power that is normally just lost to heat. If this recovered energy was then stored in some form of battery, probably a capacitor. Should the bike be driven thru the rear wheel electrically, then this energy could be transferred to that drive system. However, should it be a currently conventional mechanical drive , then the energy cycle could be reversed so the electric motor was engaged with the front tire again and the energy in the capacitor discharged via the motor to the front tire/wheel. Not sure if you would see tire smoke pouring from the wheel spinning front tire of a bucket though.

Even if it was grossly inefficient in terms of braking, then who cares, as we are still dissipating braking energy, just not all via the front brake.

What could you get out of it? Well, say there was a 10 second total braking period (for a one minute lap) and it was 80% efficient during braking and 80% efficient during acceleration, then we could experience a 20 * 0.8 * 0.8 = 12.8 kW = 17 hp hit under acceleration for 10 seconds each lap. This is on top of your 60 hp 125 cc Wobbly ported, Frits exhausted, 45 mm carb engine. Maybe the figures are a tad flaky, but I would consider that short power return to be useful.

So, possibly a touch of too much dreaming and not really suggesting that it might be feasible cos it raises all sorts of practical questions, but it embodies some of the principles that might be required to apply KERS to a race bike. Another option might be a shaft drive style rear hub at the front, driving a shaft parallel with the telescopic fork axis, with the elec motor/generator at the steering head area.

Your turn fellers.

Ken

[speedpro]

Yeah, I'm going slowly mad thinking about mine, have the ignitch pulgged in now, unable to improve on a straight 15 degrees all the way through.

EXACTLY what I got as well, straight 15 degrees was best on dyno, with only a slight gain by rolling off a few degrees right at the top.
Different combustion chamber shape would probably have changed the timing requirement though. My head has a small radius from squish to bowl.

[TZ350]

Page 960

Fuel Talk.


Re the fuel flashing off all its good light front ends.
Next time you go to a gas station have a look around and somewhere you will see several pipes stacked up in a row that are often over 6M high with a U bend on top so the outlet faces down.
These are the tank breather pipes, and the pressure head created in the tank by this high exit vent is there to contain the vapour pressure of the fuel.

When you have a 1/2 empty 20L container of petrol, within several hours the light chemicals in the fuel will flash off and create the vapour pressure you always have when opening a drum - this "good stuff " instantly dissipates to atmosphere as soon as you open the tin, and the more times you do it, the worse the fuel gets.

With fuel sitting in a kart tank, and a direct vent to atmosphere as you must have, the vapour pressure exits to atmosphere continuously, so overnight is plenty long enough to ruin the
already suspect pump gas.

The effect is much worse now that lead has been taken out, and all manner of really bad shit has been put back in to lift the octain to 98 especially.
The number of times I have seen mainly KZ2 but also KT100 and Rotax engines detoed to death by this effect is just amazing - but hey what do I know after all these years at the track and dozens of

National/World No1 plates .
The higher the tune/bmep the worse the effect you see from low octain fuel with low vapour pressure, so alot of racers get away with it, alot of the time - but with fresh fuel you can always rely
on your baseline tuning settings, without that assurance you have no chance against the guys really on the ball.


A superbike team here was pinged for running illegal fuel (not 98 PULP) they provided samples of the fuel, evidence of where/when it was purchased etc etc. The samples showed their fuel was not doctored but just very fresh fuel from a very busy servo on the Tullamarine freeway a mere stones throw from the Shell refinery.


Dead right that Avgas isnt so prone to causing issues with vapour pressure loss - this is simply due to the fact that the lead
content that has so much effect on the deto resistance,does not flash off to atmosphere.
Running the vent hose from a tank down lower than the fuel level, or into an airbox, simply means the flash off runs up, then down and out to fresh air. No free lunch.



At the petrol station the tank is underground so probably at a lower temp so maybe less vapour
the surface area of the petrol at the station is probably quite small in relation to the total volume of petrol in the tank so more light fractions are more likley to stay in the petrol. Do the tank vents in the petrol station let in more air than vapour out ?
Petrols vary widely but the RVP ( Ried Vapour Pressure ) can be upward of 9psi - thats the pressure you hear escaping when you open the drum lid.
Having the tank vent 6M up in the air creates a gas head of pressure above the fuel in the gas station tank.
The RVP climbs in the tank as the fuel evaporates until equilibrium is reached, and the rising column of gas in the vent tube continually keeps the tank under its own pressure.
A vent tube only a few inches above a kart tank does nothing.
Here is a good description of RVP and its effect.

" Now that I have the equipment to test fuel's RVP and it's relative "freshness" I have been testing almost every racer's fuel, and now am thinking about what is actually going on in everyone's combustion chambers. RVP readings indicate the presence of the fuel's "front ends" which are the first to initiate vaporization. Front (or "light") ends are critical to initiate and create fuel vaporization especially in low temperature (air and engine) engines! Remember--fuel will not burn until it vaporizes. Unvaporized fuel only displaces O2 in the combustion chambers and can short out spark plug electrodes. The misfire we hear when people "warm up" or "clean out" their race engines is a combo of lean net mixtures in the combustion chambers and unvaporized globs of fuel shorting out the plugs!

The AMA motorcycle flatrack pros say that they must now use spec fuel--Sunoco Supreme which is supposed to have RVP of 8.0psi, and sold to the racers in "sealed" 5 gallon pails. Connecticut AMA pro #2 Kenny Coolbeth was here with RLJ racing (Ron Jewell of Holley, NY) recently preparing for Daytona with a new modded Honda 450 (Ron Jewell never was able to get Kenny's Kaw 450s to quite match his 63+ hp Honda mods, so Kenny wisely jumped ship). His sealed pail of Supreme's measured RVP was only about 4psi instead of the published 8psi meaning that half of the front ends had escaped into the atmosphere between refinery and the pail! Sunoco tells me they do not put fuel in drums or pails, they only ship rail and truck tankers to wholesalers, and after that it's beyond their control. Once again we needed close to 12/1 A/F (wideband out the muffler) to make max HP at those high revs instead of the 13/1 that is most common with flattrackers who use higher RVP fuel. So surely more of the stale Supreme is going through Kenny's intake and combustion chamber in globule-form and ultimately vaporizing in the exhaust pipe.

So, if someone is tuned spot-on with his RVP pump gas blend at 13/1 out the pipe, then splurges for some of that expensive Supreme that he sees Kenny C pouring into his tank, his bike will probably slow down from suddenly being way too lean in the combustion chamber. "Over-Octaned" is the commonly offered, but incorrect explanation for the HP loss.

Lower than published RVP is very common--the last test I did on some VP Import fuel for a turbo two-stroke measured ZERO psi meaning it was DOA in a sealed pail. Yes, we were able to use it, but we were careful to have the engine smoking-hot (engine heat helps vaporize the stale fuel) and A/F in the conservative 11.5/1 range--staying far away of the 13/1 max HP A/F ratio".


And this is starting to answer the question I posted pages back about what was happening with my dirt bike that it often would run dreadful until it had passed through the gearbox then would run sweet. Yet 2stroke drag bikes run cold.

I was wondering about the physics of why.

Of course the dirt bike has old gas in it. Even some residue in the bowl, but has to use old gas and worst effect is when it is cold. Once the engine is hot the fuel will vapourise better.



I'm not keeping up, they were running leaner by exhaust reading to run richer in the blast pot?

NO - when globs of fuel do not vaporise, they pass thru the engine unburned and this gives rich readings on both egt and Lambda.
If this situation is " fixed " by the tuner jetting down, we then get a chemically lean condition in the combustion space but this then reads as "normal " for best power at say 13:1.

This is what happens to the KZ2 engines that regularly deto the piston and head to death,when crap fuel is being used with what the driver thinks are safe jets.
In the quoted article, they kept the bad fuel under control by not going leaner than 12:1,this saved the engine, but made alot less power.


Fuel vaporisation is very good with a carb such as the Lectron, and for years it has been seen that these carbs are way less sensitive to A/F ratio than your average VM round slide Mikuni for example.
If you read the marketing blurb by SmartCarbs, they are telling us that the fine mist from that carb is way better than that we get from what we would regard as normal injection.
But running super high pressures and or air over fuel as we see in Etec etc may ameliorate this , dunno.


To answer the two questions, yes fuel mist will drop out of suspension and become raw fuel sitting on the walls of the ducts.
Conventional wisdom tells us that in a 4T this can be minimised by making the inlet port walls surface finish equivalent to 180 grit wet and dry. Now this is interesting as in most cast 2T transfer ducts end up being around this number - and so called " beautifully " cast ones and those polished up by
expert tuners end up way smoother - loosing power in the process.

The other question around the SmartCarb fuel needle issues.
I told them right at the beginning that the only way to enable fine tuning of the carbs - especially when on a twin Banshee for example, was to run a powerjet with very small jet increments as Lectron
did with great success very early on.
But they are /were so enamored with their own cleverness re the insensitivity of the carb thus not needing to be fine tuned, I was ignored.

The possibility was / is there to finely emulsify the powerjet fuel using the so called AdjustaJet principal of having a variable air bleed into the powerjet suction circuit but sadly
some horses dont even like water.
Those carbs do work supremely well, but seems for now the only way to get fine tuning is to be fucking about sanding the needle tips with a digital micrometer in the other hand.


Sorry Frits I gave the wrong impression with that statement, but as per the article I quoted above ( from Dynotech Magazine a superb mine of info on 2T testing )
"unvapourised fuel only displaces O2 in the combustion space " so we do have excess fuel dropping the egt and if the engine is then leaned down it will deto due to the actual lean condition in the chamber.

But if using Lambda we cannot run fuel that has low amounts of light front ends at the "normal " best power ratio of 13:1 as the unburned droplets contribute nothing to the combustion process.
So the actual " burning " A/F ratio in the chamber is in effect lean.
As in the Dynotech example they gave they had to run under 12:1 or the engine would have been destroyed by deto in an instant, when running the new fuel with zero RVP.


I have done the tests on a Superflow and the so called HV Lectrons will outflow a size for size Mikuni or Kehin easily , and ,as say a 38mm HV has a 34mm venturi
behind the slide it acts like a much smaller carb at 1/2 throttle.
In Europe I know they are using 30mm Lectrons on 50cc race engines with great success.
The SmartCarb does not have a venturi, but has an egg shaped bore at the slide that probably does the same thing.

They also have an aux venturi above the top of the entry trumpet, that is connected to the bowl air space - and it is this that gives the carb its auto adaption to air density,be it weather or altitude.
This for sure works a treat, with no jetting change when climbing Pikes Peak - but at the moment they do seem to be having endless trouble getting the things into the ball park at sea level.
At this stage Lectron do have a huge range of incremental needles to suit any application and also have a powerjet with very fine flow sizing that makes fine tuning a twin super easy.
I have just got a 30mm SmartCarb here for a Giggle project , so if someone with 1/2 a clue wants to do some testing im sure we could arrange something.


Here is a link to DynoTech,that mentions stale fuel as well.
I have been using the copper tube deto detector into my dyno headphones for years, so as im in a good mood again today here is the detail
on how to do it and why.

http://www.dynotechresearch.com/blog/archives.asp?chosenMonth=4&chosenYear=2013#294

Nowdays, I like to use the Czech deto box running into the dyno data logger, so i can see at a glance where the deto occurred exactly.




I was dreaming late last night ( about 2Ts - what else ) and thought thru the statement that Frits was questioning ( a complement to a very skilled bullshit detector that man I must say ). Maybe the logic of " unvapourised fuel only displaces O2 in the combustion process " leads to the Ex gas then also being low in O2 so the Lambda reads rich ?

I dont know to what extent ie what % of O2 can be displaced by fuel that is never burnt, and if that level is then sufficient to affect the Lambda reading.

That then leads me to the question - wouldn't a continuously misfiring engine read rich on the Lambda, and isnt that then the same end result as unburnt fuel droplets passing thru an engine?
This is too early in the morning for this - I need strong coffee.
I hope you had that coffee, Wob. And as you are ten hours ahead of me, I suspect you are sipping something tastier by now.

First let's look at the 'logic' of unvaporized fuel displacing O2. The fuel is carried into the combustion chamber by the air; air and fuel are in there together and there's no way that the air could be forced away by unvaporized fuel droplets.

Unvaporized droplets won't be doing much forcing anyway because the volume of an unvaporized droplet is about a thousandfold smaller than the volume of a vaporized droplet.

Wob, detecting bullshit is quite easy if you produced that bullshit yourself in the past.
I once ran an engine on the test bench and the Lambda sensor said 'lean', or so I interpreted it at the time. So I jetted up.

Then the Lambda sensor said: 'now it's even leaner!' What really happened was: at the first test the engine was so rich it was misfiring. And no combustion meant: unused oxygen in the exhaust gas.
Naturally when I jetted up, the misfiring became worse, even more combustion cycles failed and even more unused O2 hit the Lambda sensor.

Lesson learned: a Lambda sensor does not say 'rich' or 'lean'. All it says is: I see ogygen'.
Amazing Frits how complex logic can get, and more amazing that in reality its all simple when you finally get to understand. Of course Lambda only reads the O2, what a dumb shit.


FUEL DROPLET SIZE REALITY CHECK

Some pages ago, there was some discussion on fuel droplets. Got me thinking as to what size a fuel droplet might be.

So, using the RSA 125, 54 hp @ 12,000 rpm as an example. Rounding numbers as we go, this equates to 40 kW. Referring to an SAE paper 2004-01-3561, the instrumented dynamometer performance of a Honda RS125 engine was measured and compared to various computer predictions. This showed a best BSFC (brake mean specific fuel consumption or basically fuel mass flow rate per unit of power) of 400 gm/kWhr. Using this figure as a general guide, we can calculate a fuel flow rate of 40 * 0.4 = 16 kg/hr = 0.27 kg/min = 270 gm/min.

At 12,000 rpm, this gives us 0.023 gm/cycle. Using a fuel density of 0.74, this gives us a fuel volume per cycle of 0.031 mm^3.

If this was a cube of fuel, it would be of (0.031)^0.333 = 0.31 mm per side or if a spherical droplet, it would be of (0.031 *3/4 * π)^0.333 = Ø0.4 mm.

Pretty small stuff really, not something like the Ø3 -4 mm as one might imagine a droplet might be.

Taking this one stage further, if the A/F ratio was 12:1, this would mean 0.023 * 12 = 0.28 gm air was entering the engine per cycle. Using an air density of 1.2 kg/met^3 (at sea level & 15 deg C), this would give us a volume of air entering the engine of 0.000233 met^3 = 233 cc. From this the Delivery Ratio can be calculated at 233/125 = 1.87 : 1. This is pretty good, and sort of correlates with the DR indicated in the SAE paper of around 1.4 : 1, this engine under their test conditions was around 30 kW, not the 40 of the RSA.

Comparing the 233 cc to the volume in the cylinder at the time of exhaust port closure. This (trapping) cylinder volume at the time of exhaust port closure (based on a 120 mm rod, 54 stroke and 192 exh open duration, gives a stroke of 27.45 mm from port closure to TDC) would be 63 cc.

So, ignoring all temperature rises and pressure variations, this means we are stuffing 233 cc of air into a 63 cc volume, a ratio of 3.7 : 1. Some time ago on pitlane.biz, Frits (I think) stated that Jan Thiel took the entire exhaust off the RSA engine and tested it. Would have been a tad noisy I’d imagine. It obviously would have had no benefit of any harmonic supercharging (as with the expansion chamber) and resulted in a power output of 18 hp, compared to the 54 hp which is 3 times the power. Sort of matches the 3.7 : 1. Tells you just how useful the expansion chamber exhausts system.

There you go, a bit of rough trivia.

Ken




Ok my problem; along standing issue of ring seal and bore wear. MB100 running KT100 piston. Both steel bore std so ring are compatible.

There was an. Issue when the. Rod continued on its path extending the inlet port to the bottom. As I've case reeded it I've glued some ally in the hole to make a boost port fully formed. So I do have a question that this lack of support at the bottom could be affecting the bore at the top. But I've never had the ally crack it's epoxy or fall out and the barrel is complete for a cm below the ports so should be ok.

anyhow I always get a polished bore above the ex and the boost port. Always wears there and a hone won't bring it back round easily. The area is scooped out above the exh the longer it runs. I'm also seeing scooping above the boost port. Running 20:1 castor oil. Ex port is 68% width , heavily chamfered and very oval and symmetrical. Ring seal has never gotten better than 25% (often much worse) despite using torque plates and heating to operating temp before honing. KT runs say 8% as comparison . Barrel is water cooled now.

so the KT piston runs it's ring peg centrally at the back over the open back boost port which we all knows works in many engines from where I first saw it in the 256. A difference I'm wondering is that the Rotax and everything more modern is plated. Contemplating one more go last oversize moving the peg to between boost and transfers. Thoughts?
The rod angularity is at a max 1/2 way down the bore so if the lower skirt isnt supported properly the piston will cock over, dragging the ring edge into the bore and creating the wear pattern.

Dump the 18th century fish and chip cooking oil and get something in there that has at least a modicum of film strength. Whiiir.CLICK. ok we'll get to that later.

Ahh Wob, you have a way with words that makes me laugh. . usually at myself.

I'd only changed to Castrol R30 in an attempt to get better ring sealing. I thought the old bean oils were supposed to have surprisingly good film strength esp when hot (& teh bike was air cooled not that long ago).

Anyways, since it has a full reed conversion I trimmed the back of the piston from 56mm to 48 as it stuck down in the way at BDC. I'd noted the old aircoold YZs had most of the piston back missing and the KT100 .skirt was reasonably long and parallel. A few pages back you indicated that the most flow isn't happening at BDC. Perhaps I should go back to full length skirts (except on Saturday nights when its dark).


Most of the transfer flow IS at around BDC if the pipe is correctly designed to give max depression at this time.

Inlet flow occurs when the case starts to go negative ( and helped by the inlet length if its tuned correctly, as this goes positive ) due to the pipe suction pulling the mixture in the ducts into the cylinder,and this depression eventually opens the reeds via the case,near BDC as well. Thus piston holes, Boyesens and short skirts all help the initial flow as the piston starts to rise.

Bean oil always has had crap film strength, what it does have is the ability to give a nice smooth wear surface - as you said when things get real hot it retains this superior wear pattern, wheras a full synthetic disassociates into non lubricating shit chemicals.

But the new generation of oils based on esters that mimic castor but have the huge film strength of synthetics are way superior to both.

The best oil from much testing by many clever tuners for the air cooled KT100 now,is Elf 909, the most castor like of the new blends.

In my testing the best oil now for watercooled engines on pump gas that get close to being overheated by 640C in the header like we used to on Avgas, is Motul Kart at 20:1.

The super oils like Elf 927 were developed for unleaded race engines, as these run fastest when alot richer than a leaded setup and they never see the temps that killed full synthetics badly.

If you want to get the best cylinder surface on a new chromed bore, then slober R30 all over the place, mix it up at 16:1 and ONLY idle the new engine for 5 minutes.

This reduces the ring tension from high cylinder pressure, and the castor oil lets the ring/bore surfaces wear in to each other smoothly.

Once this is done, dump the castor and go racing hard on a semi synthetic.
Ive won dozens of titles with engines done this way.


How is the exhaust bridge? Seems like the problem that the gasgas has, pegging the ring in the bridge, solution was to drill 4 holes with 1.5mm chamfered to 2mm.

Or another note, what do you guys think about the shell racing M oil?
I can't run it on the 125, fouls plugs like there is no tomorrow, A747 doesn't do anything like that, but runs great in the cast iron 45mm CRM liner.


Well as I said, fully synthetics like 2T are not good when overheated in an engine that runs leaded race gas. Where the normal running temp needed to make the fuel work correctly, destroys the film strength - the only good reason to be running a full synthetic in the first place. And at 30:1 it would struggle in any real race engine.

I had no idea you could still buy A747 - easily the best oil made for leaded fuel, many years ago.
Shell M was developed in the stone age,for use with Methanol fuels, so no reason to be using it for anything else, or at all really.

I wouldnt put Amsoil in a race engine if it was given to me, and it ran at only 5,000 rpm.
Last engine I saw on Amsoil, was a microlight that had crashed, due to a skirt dropping off.
The other piston was OK, except for the 0.012" bore clearance after 3 Hrs in the air - running 100:1 like it said on the bottle.

Every RS125 by Honda should have 2 bridge lube holes and 1 each side of the boost,unless you want to be freeing snagged rings all the time.

A T port is absolute hell on any oil trying to keep the ring off the bore, even with super trick piston shapes and properly relieved bridge geometry.



Very good. Reeds are chipping a little even at modest revs with piles of oil.Motul 800 a similar brew as Castrol 2T but as I said the much later Motul Kart product seems to be a very good imitator of castor - the 800 certainly wasnt, with every engine I pulled down being very "dry" unlike Kart where everything is covered in a slobbery wet film. 20:1 shows gains in the aircooled KT100, but not so much in a watercooled, except in reed engines where the richer mixture always helps reed cushioning and prevents incipient tip chipping.


Ok I found something interesting. it says nothing about this in the ingredients on the data sheets

'Thanks to its high content in specially selected Ricinus oil, ELF HTX 909 provides exceptional
protection against gripping.'

http://www.nkp-karting.com/uploads/products/files/HTX 909 EN.pdf

revised 2-20-2014 http://www.quickfds.com/out/16986-29245-27967-017784.pdf


The 909 oil mix seems to be specifically directed at the 20,000 rpm direct drive 100cc kart engines, and as I said its for sure the best oil today for the aircooled
KT100 Yamaha, as I have done the direct testing for a customer who is one of the top tuners here.

Those guys are all die hard castor users, and it has taken several years to convince them the 909 is " better " but now they all use it.

Running the 976 full synthetic always lost power on the dyno when run very hard at 650 + in the header, as all top Yamahas do.

This was designed specifically for the unleaded GP engines, that dont run super hot like we did back in the day of full leaded rocket fuel, nor like they do in aircooled race engines.
Here is an old dissertation on how castor works.

http://www.go-cl.se/castor.html


So as I read that if you're aircooled run Castor or ideally 909. If yer watercooled run a decent synthetic ester oil.

I'm assuming you don't consider Av as being a hot burning GP like rocket fuel, its just all that we can run vs pump fuel.


AvGas runs best exactly like the old leaded rocket fuel, if you dont have 650*C in the header you aint doin it right.

So yes 909 is for sure the best in an Aircooled running hot at 650*, but is equally fine in a watercooled on AvGas - just dont use a full synthetic in anything
that runs AvGas properly.

Find some old A747, or stick with Elf 909 or Motul Kart.
If you are running unleaded properly at rich ie cooler temps, then spend up large on Elf 927 full noise synthetic if you feel the need..


I get Elf oils at distributor prices if any one wants some for T2 or T4 bikes


We used this castor mix oil for the first time when winning the KZ2 Nationals.
I havnt dynoed it yet, but will do soon after a rebuild is finished.

http://www.kartsport.org.nz/about-us/hot-topics/xeramic-kart-lubricants-now-available

Seems most top kart teams use this now, no one gets it free, so they must have tested it to death in Europe.


Huge EGT temps mean Jack Shit, I have seen idiots with a stock head TZ350 running 2 base gaskets that saw 1360 for 20 laps without seizing.
But funnily it was 5 seconds off the pace of a properly tuned one running 1245/1255 on AvGas.
Getting the max com and max advance possible for the fuel ,without deto is the key - and for AvGas or up to 110 race gas ,mid 1200s at max power means you are on the money.
One jet leaner , if it only sees around 20 to 30* hotter, means the optimum is back one jet richer, as the perfect scenario is 50 to 60* per jet change, as this always gets back to the max power available.
Sure the oil must be good with so many top teams running it, but telling me you have seen 1300 ( like some sort of red badge of courage ) just means the rider wasnt watching the gauges/and or ignored
the warning lights ( and should be shot ) or someone made a wrong tuning call on an engine that wasnt on the money to start with.
On unleaded it would be detoing unhappily around 100* richer at 1200 if tuned to the edge.
If it was really on the limit, it would have locked up at 1300 ,no matter what oil was on the bore.


That was a bit of a rant - but having riders tell me afterwards they saw over 1300 on the gauge, but dont understand why the bloody motor siezed
because they didnt change the jets ,from coming off the dyno really piss me off.

[Drew]

Page 960 already!!!

Dude, go into your settings and tell me how many posts per page you are showing. My feed says page 720 and no multiple of five makes that 690.

Edit, maybe I can since it's 960. My bad.

[TZ350]

Dude, go into your settings and tell me how many posts per page you are showing.

I see page 960 and thought the page numbering system was the same for everybody, but can people chose to display a different number of posts per page and therefore see a different total number of pages on this thread?

I ask because on most every tenth page I have been posting collections of links to the last lot of the better technical posts for easy reference for those of us that are interested in two stroke tuning and never thought that other people may have a different page numbering system to what I see.

[Drew]

I see page 960 and thought the page numbering system was the same for everybody, but can people chose to display a different number of posts per page and therefore see a different total number of pages on this thread?

I ask because on most every tenth page I have been posting collections of links to the last lot of the better technical posts for easy reference for those of us that are interested in two stroke tuning and never thought that other people may have a different page numbering system to what I see.

Yeah, it's optional up to 80 posts per page. I had to change mine to try and line up with your count, but I seem to have failed.

[TZ350]

Yeah, it's optional up to 80 posts per page. I had to change mine to try and line up with your count, but I seem to have failed.

Ok ... I did not know that it was optional, makes sense though. Mine is just the default setting, whatever that is.

[Drew]

Ok ... I did not know that it was optional, makes sense though. Mine is just the default setting, whatever that is.

15 I think. Finally sussed it by restoring site default.

Now, where do I find the index?

[Haufen]

EVERYTHING makes a difference in these fekin things, dont assume ANYTHING.
I have been wanting to try reed spacers on a KZ2 kart engine for ages, having spotted one on the grid fitted to the enemy's engine.
So prior to the Nationals at Easter I finally got our good TM onto the dyno to recheck the performance with a new "high inertia" crank.
The crank replaced the so called " factory special tune " version that costs some E600 from TM for a KZ10.
I got hold of the wheels for an old KZ9 that were very simple in that they are plain disks with only 1 piece of Mallory opposite the pin for balance - nothing else.
So I added two 19mm by 19mm Mallory slugs in each wheel, on centreline so the balance isnt affected, only the rotating inertia.
Short story is this mod lost 1 Hp all the way to 13200 where it crossed just under peak Hp - high inertia = harder to spin up ( I think )
After peak Hp the lines diverged, and at 14500 the thing made 6Hp more,up from 35 to 41, with a much smoother roll-off ie no " fall of the cliff " effect.
This enabled at least a 1/2 tooth to be added at the rear, well off setting the 1Hp loss with way faster off corner acceleration due to gearing torque multiplication.
I added a 5mm reed spacer and this lost around 2Hp below 11,000,gained 2 Hp between 11,000 and peak, then lost that 2 Hp and more after, getting progressively worse.
So I started playing with reed and backup tensions,using softer main petals I got back the loss under 11,000 and with wider/stiffer backups,spaced further away from the mains
I got back nearly all the overv loss.
So of course I then took the spacer out to recheck, and it made even more power everywhere,fucked if I know,enough to drive you up the wall - but hey it took the National title so who's complaining now.

Thanks for this interesting insight. Did you / could you test the engine on a stationay dyno, also? Or did / were you able to change the spin up time on the inertia dyno? And if not, are you planning to do so? I think the results would be very interesting if the effect is due to inertia.

[F5 Dave]

but, what, how?:wacko:. If the crank weight can affect power curve, surely it would be different in every gear. It's all very odd.

but yeah dyno time usually raises more questions. Not so often power increases.

[Ocean1]

Short story is this mod lost 1 Hp all the way to 13200 where it crossed just under peak Hp - high inertia = harder to spin up ( I think ).

How can it be otherwise? It's work that has to be done in order to increase revs, same as the dyno load itself, and every other parasitic load in between. Most other motorsport disciplines find advantages in trimming rotating mass. I once made an alloy flywheel for a mini, which has a monster standard flywheel. No dyno, but against a known comparable machine over the same distance there was a couple of car lengths in it.

I understand crank mass was one of the variables Yamaha were trying to mess with in their analysis of comparable power characteristics between V twins and IL4s, they quantified crank inertia separately from "normal" power delivery and immediately their numbers agreed with real world track telemetry. They also mentioned the significant issues rotational inertia caused under brakes. All of the energy expended in spooling up the extra mass was completely lost on deceleration, a feature you also found on the dyno as you approached max revs, yes?


but, what, how?:wacko:. If the crank weight can affect power curve, surely it would be different in every gear. It's all very odd.

Why would the power curve be different in every gear? Power at the crank would be the same in each gear, no? And the difference in leverage represented by each gear change would apply to energy at the crank, no mater what shape it's curve.

[F5 Dave]

Yeah but if the work has been done and the power curve is falling surely it isn't storing 6hp and the load will be different

[wobbly]

The only difference the gearing makes to the power curve as seen off an inertia dyno is the run time.
In 1st gear it would spin from 6000 to 14,000 in an instant.
Not long enough to get the correct heat level into the pipe.
I usually run it in 4th gear as this acceleration rate is all but identical to what happens in the data readout on track.
After doing 3 full throttle pulls, the pipe surface is up to temp, I then do 2 recording runs back to back and overlay them.
They are usually then identical within 2/10 of a Hp so I choose one and delete the other.

There have been arguments for years over crank inertia in a racing 2T, with the basic theory being that with more inertia the in cycle speed variation is reduced.
At TDC where alot of work is done compressing the combustion charge, the crank slows down - to where it then accelerates very quickly toward BDC and speeds up as the
piston runs over the transfers.
This theory has been rubbished by some clever minds, BUT, bottom line is that it was discovered instantly when HRC offered total loss setups derived from A kit parts
that simply removing the flywheel lost ALL the overev power.
Ive done it, when I first started using Ignitechs on the old MX based RS125 Honda - ditch the flywheel and it simply WILL NOT rev out.
So the factory and VHM came up with so called " high inertia " cranks to be used with total loss where no flywheel was used.
This also then enabled lighter ones to be used for short tracks, favouring acceleration, or even heavyer ones for big tracks where overev power is king.

Jan has stated that he could find no advantage to so called heavy cranks on the Aprilia, but that I am sure is an artefact of the design being very " heavy " to start with
and making it higher inertia again simply ran into the law of diminishing returns.A very heavy crank is simply too slow to accelerate, and nothing worthwhile is gained in the top end against that loss.
A stock RS125/250 Honda has a VERY light crank compared to the Aprilia that is full of lumps of heavy metal.
I have recently built cranks for a couple of customers with very expensive Rotax derived tandem twins, using full circle wheels with no steps and full of heavy metal balancing like the Aprilia
and all report amazing gains in overev ability,cylinders and pipes etc being identical.

[Ocean1]

Yeah but if the work has been done and the power curve is falling surely it isn't storing 6hp and the load will be different

But it is storing energy, all of the energy it absorbed on acceleration. And that energy will be the same over any given pull, no matter what the gear, it's effect is just seen over longer times in higher gears.

As the power curve approaches peak the energy stored in the rotating mass begins to shed power back into the dyno load. That's the over-rev capacity Wobb's seeing with heavier cranks, it doesn't come from combustion pressure, that's declining.

Edit: Worth noting that the extra power delivered beyond peak power revs derived from flywheel mass is transient. A fact you won't usually see on an inertial dyno, because with a static, (invariable) load you can't hold peak revs long enough to see it flatten out. On a brake dyno you wouldn't even see it to start with, you normally collect data at constant revs.

[Ocean1]

The only difference the gearing makes to the power curve as seen off an inertia dyno is the run time.
In 1st gear it would spin from 6000 to 14,000 in an instant.
Not long enough to get the correct heat level into the pipe.
I usually run it in 4th gear as this acceleration rate is all but identical to what happens in the data readout on track.
After doing 3 full throttle pulls, the pipe surface is up to temp, I then do 2 recording runs back to back and overlay them.
They are usually then identical within 2/10 of a Hp so I choose one and delete the other.

There have been arguments for years over crank inertia in a racing 2T, with the basic theory being that with more inertia the in cycle speed variation is reduced.
At TDC where alot of work is done compressing the combustion charge, the crank slows down - to where it then accelerates very quickly toward BDC and speeds up as the
piston runs over the transfers.
This theory has been rubbished by some clever minds, BUT, bottom line is that it was discovered instantly when HRC offered total loss setups derived from A kit parts
that simply removing the flywheel lost ALL the overev power.
Ive done it, when I first started using Ignitechs on the old MX based RS125 Honda - ditch the flywheel and it simply WILL NOT rev out.
So the factory and VHM came up with so called " high inertia " cranks to be used with total loss where no flywheel was used.
This also then enabled lighter ones to be used for short tracks, favouring acceleration, or even heavyer ones for big tracks where overev power is king.

Jan has stated that he could find no advantage to so called heavy cranks on the Aprilia, but that I am sure is an artefact of the design being very " heavy " to start with
and making it higher inertia again simply ran into the law of diminishing returns.A very heavy crank is simply too slow to accelerate, and nothing worthwhile is gained in the top end against that loss.
A stock RS125/250 Honda has a VERY light crank compared to the Aprilia that is full of lumps of heavy metal.
I have recently built cranks for a couple of customers with very expensive Rotax derived tandem twins, using full circle wheels with no steps and full of heavy metal balancing like the Aprilia
and all report amazing gains in overev ability,cylinders and pipes etc being identical.

I don't see any contradiction in any of that. I helps me to visualise crank mass, (and every other rotating mass in the system) as a big bungy cord between my throttle and the back wheel, it only costs me overall acceleration potential if I let the bungy cord go before it's recoiled. If the type of racing in question doesn't lend itself to holding on to that bungy cord beyond peak power revs then low mass is the go. Like F1, not only zero flywheel but super light billet HT steel alloy cranks.

[Sketchy_Racer]

Head inserts on an air cooled motor?

How well will these work? I can only assume that the joins are going to make for a less efficient thermal path to dissipate heat from the combustion chamber. But how well will they work?

Has anyone here tried them?

[Frits Overmars]

Why would the power curve be different in every gear? Power at the crank would be the same in each gear, no? No.


But it is storing energy, all of the energy it absorbed on acceleration. And that energy will be the same over any given pull, no matter what the gear, it's effect is just seen over longer times in higher gears.True, the energy stored in the engine inertia only depends on the initial and final rpm and on the amount of inertia, irrespective of the rate of acceleration.
But the power generated by the engine is very dependent on the rate of acceleration and the rate of pipe temperature variation. This rate should match the rate of crankshaft rpm rise. As Wob said:
In 1st gear it would spin from 6000 to 14,000 in an instant. Not long enough to get the correct heat level into the pipe.

As the power curve approaches peak the energy stored in the rotating mass begins to shed power back into the dyno load.You struck me as a bright mind, so you might want to think this over once more :rolleyes:
Energy stored in any rotating mass does not become available until the rotation is slowed down. In racer's terms: when we don't want it any more.

[Frits Overmars]

Head inserts on an air cooled motor? How well will these work? Very well if you're looking for detonation. Not quite so good if you're looking for power.
I can only assume that the joins are going to make for a less efficient thermal path to dissipate heat from the combustion chamber.Right. And 'less efficient' is putting it mildly. I would describe it as 'catastrophic'.



But how well will they work? Has anyone here tried them?A mate of mine races a Suzuki T500 with head inserts. It is one of the fastest bikes in its class. But I keep saying it could be a lot faster still :yes:.

[TZ350]

Head inserts on an air cooled motor?

How well will these work? I can only assume that the joins are going to make for a less efficient thermal path to dissipate heat from the combustion chamber. But how well will they work?

Has anyone here tried them?

I have not tried a head insert, and I don't think the thermal interruption will be a help but if your determined to go air cooled. A copper head gasket that also forms the squish band and extends out to be a fin or a pair of fins like the one in the picture could help. As it gives the squish a very good cooling path (in air cooled terms) and if you have a flat face across the insert and head the copper will form a thermal path that marries the insert and head fins to a certain extent.

297875

Copper has twice the thermal conductivity of aluminium so will shift heat from the squish to the outer fins faster than it would have traveled through an uninterrupted area of aluminium of the same cross sectional area. The copper will also pick up heat from the insert face and transfer it to the outer head fins.

If I was going the insert way, I would make it as big as possible with large flat faces to maximize the joint area for greater thermal transfer. For head fins I like to use 2mm copper when I can get it and would try 3mm copper if I could find it.

Copper is not that suitable for making a complete head as its too soft and the plug threads pull and the head bolts tend to squish it out of shape over time. I once had 1.5mm of copper metal sprayed over the face of an alloy head so there was a good copper thermal path from the inner face of the combustion chamber shell out to the outer head fins.

The problem was that the polished copper in the combustion chamber oxidizes and goes black. Shiny copper is an excellent radiant heat reflector and black oxidized copper is an excellent heat absorber and is not what we want. But I found a good silicon car wax helped keep the polished copper combustion chamber shiny for a lot longer. The squish area does not seem to suffer from this oxidizing problem.

Because shedding thermal energy through air cooling is more efficient the hotter the radiant surface is, I started looking at copper as a way to shift more heat from the combustion chamber area to the outer fins and therefor run them hotter and get them to do more of their share of the cooling work than they would normally have done. With copper, in theory, if you can normalize the heat gradient more across the head by getting the outer fins to run a little hotter then the inner fins and combustion chamber shell will run a little cooler than they would have before.

[koba]

Lapped taper around the circumference for maximum contact?

[Ocean1]

True, the energy stored in the engine inertia only depends on the initial and final rpm and on the amount of inertia, irrespective of the rate of acceleration. But the power generated by the engine is very dependent on the rate of acceleration and the rate of pipe temperature variation.

Yes I see that, but I was referring to just inertial energy, which as you said is purely a function of mass over acceleration, same on every pull.


You struck me as a bright mind, so you might want to think this over once more :rolleyes:
Energy stored in any rotating mass does not become available until the rotation is slowed down. In racer's terms: when we don't want it any more.

Not sure I see that. But I'm not very good at painting these sort of pictures... As revs increase beyond peak and power increase begins to drop is there a point where inertial energy begins to affect revs positively compared to the same engine with less mass?

Nevermind, the picture is clearer.

Edit: which means Wobb's over-rev capacity from heavier cranks can't be sustainable, if you could load the dyno to restrict revs to that over-rev limit you'd see power peak at those revs and then drop as the inertial energy was expended.

[jasonu]

The only difference the gearing makes to the power curve as seen off an inertia dyno is the run time.
In 1st gear it would spin from 6000 to 14,000 in an instant.
Not long enough to get the correct heat level into the pipe.
I usually run it in 4th gear as this acceleration rate is all but identical to what happens in the data readout on track.
After doing 3 full throttle pulls, the pipe surface is up to temp, I then do 2 recording runs back to back and overlay them.
They are usually then identical within 2/10 of a Hp so I choose one and delete the other.

.

This is how Chris and I more or less always did our dyno runs and we got some pretty consistant results. Other 'experts' recommended we do the runs in top gear for some unexplainable reason.

[wobbly]

I have seen inserts done for a aircooled that had something like 6 staircase steps on the mating surfaces.
Each of the steps OD faces were a press fit, and the accuracy was good enough that all the horizontal flat surfaces would also be in contact.
Dont know if this would be better or worse than a conical outer shape to the insert that mated against the same surface on the inside of the
head cover - with the head bolts clamping these surfaces together.
As both ideas support the inner dome over a wide area, maybe the insert could be done in copper to aid thermal transfer to the outer finned cover.

[koba]

Has anyone ever 'solid' mounted a carb before?
I mean running without any rubber Manifold.

I was thinking of recreating the standard MB style with some welding, it would have a plastic section as a thermal barrier but no rubber mounting.

I remember it a mates Rally car we had major issues with the fuel being shaken up in the side-draughts until we got them mounted with enough flex to slow the rattling.
I'm thinking we don't get quite the same shaking...

If it works I should be able to loose about 20mm from the inlet tract.

Anyone have good or bad experience here?

[Sketchy_Racer]

Has anyone ever 'solid' mounted a carb before?
I mean running without any rubber Manifold.

I was thinking of recreating the standard MB style with some welding, it would have a plastic section as a thermal barrier but no rubber mounting.

I remember it a mates Rally car we had major issues with the fuel being shaken up in the side-draughts until we got them mounted with enough flex to slow the rattling.
I'm thinking we don't get quite the same shaking...

If it works I should be able to loose about 20mm from the inlet tract.

Anyone have good or bad experience here?

Yep, I had a solid mount on a old dirtbike. Old XL125s etc all had solid mount carbs. The rubber inlets are usually just for easier manufacture of the reed stuffer on 2Ts I would assume

[koba]

Yep, I had a solid mount on a old dirtbike. Old XL125s etc all had solid mount carbs. The rubber inlets are usually just for easier manufacture of the reed stuffer on 2Ts I would assume

Sweet, I'll give this a go, I was just worried because if it doesn't work I'll have wrecked a carb.

[Drew]

Sweet, I'll give this a go, I was just worried because if it doesn't work I'll have wrecked a carb.

The GL motor didn't like it. But don't piston port bikes usually mount solid? The GT does.

[koba]

The standard MB does too, I think I'm just being a scaredy pants.

[TZ350]

297901297900297899

Finally got some time to work on the Beast. Fitted the generator set that Wob sent me, it needed a little modification to fit the GP but it worked out well and everything lined up OK. Changed the flywheel center for a KX80 one, as the KX80 taper fits the GP crank and the rivet holes lined up with the new flywheel. I used high strength epoxy resin to glue the face of the KX center hub to the flywheel and replaced the old rivets with shoulder bolts, hopefully this will work out OK. Will finish the wiring this week, then I will have power to burn for running the EFI fuel pump and the fancy cooling fans.

[F5 Dave]

The standard MB does too, I think I'm just being a scaredy pants.
Vibration can be a major concern. However Frits had posted up a version using an o-ring for a super short manifold, remind me sometime.

[TZ350]

Hi there,

297908

the results of the 8th & final round of the 13/14 season of AMCC bucket racing from today are attached, Tim will be updating the website.

Congratulations to the winners:
F4 Rick Ford
F5 Tim Fraser
B grade Pete Leahy
C grade Helene Conway
Sidecars Rick & Henk

No Diproses this season, even though Nathanael did win the last 10 F4 races in a row… (out of 16 total)
I guess if I want to win anything I should stop falling off my mountain bike.
Regards,
David Diprose

[TZ350]

Hi all,

The final round (round 8) of the Auckland Bucket Championship was held under sunny skies on Sunday June 15.

The detailed race results can be found on Mylaps here: http://www.mylaps.com/en/events/1034514

The final championship standings can be found on Mylaps here: http://www.mylaps.com/en/championships/31443

Congratulations to the new class champions:

F4 Rick Ford
F5 Tim Fraser
B-Grade Pete Leahy
C-Grade Helene Conway
Sidecars Rick & Henk

Two Strokes take out :first: :second: in F4 and :first: :second: :third: in F5

[speedpro]

Two Strokes take out :first: :second: in F4 and :first: :second: :third: in F5

and EVERY race on the day except sidecars

[TZ350]

The Beast is starting to snarl and it will pull away in top gear on the dyno from 3500rpm and WOT.

292749

Red line is the best ever using a carb with this old cylinder and the Blue line is where I am at with fuel injecting it. In all fairness for a proper comparison it needs a new head and a generator for the EFI. I am pretty excited about the Ecotrons fuel injection system as its starting to be very easy to work with. I think this EFI business is going to work out OK.

Well, we have a good head and just about finished wiring the generator and installing the four channel temperature data logger.

Dyno time soon .... :banana: hopefully have the Beast track ready for the new season.

[TZ350]

Two Strokes take out :first: :second: in F4 and :first: :second: :third: in F5and EVERY race on the day except sidecars

A two stroke side car with CVT is being built. Shishhhh ... you did not hear that from me.... :o

[husaberg]

Vibration can be a major concern. However Frits had posted up a version using an o-ring for a super short manifold, remind me sometime.

http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130375552#post1130375552

[TZ350]

297918

Just musing, but I have seen 2 into 1 expansion chambers before, they make a real weird noise. Anyway I was thinking of something different, a 1 into 2.

Because the new engine will have a power valve that changes the exhaust timing from 80 deg atdc to 90 and back I have been thinking of two expansion chambers with a butterfly in the header that switches between them so that whatever the exhaust timing the working chamber suits it.

Possibly a step better than an ATAC valve. Anyway, like I said, just thinking about it but you can see how possible it would be to put a butterfly in the header to switch between chambers.

[Frits Overmars]

Because the new engine will have a power valve that changes the exhaust timing from 80 deg atdc to 90 and back I have been thinking of two expansion chambers with a butterfly in the header that switches between them so that whatever the exhaust timing the working chamber suits it. I have been working on a ZABEL 700 cc two-stroke single for sidecar-MX. The guys with the heavy boots want power from 2000 to 8000 rpm, so I had to dive into power valve calculations once again (a trombone pipe would do much better, but I'm afraid it wouldn't last long in MX).
A good power valve may adapt exhaust timing to pipe dimensions and rpm; an average powervalve will spoil some of the exhaust pulse's energy so it won't do too much harm to the power curve when it returns too early at low revs, but all powervalves reduce the blowdown angle.area far more than is desirable, with consequent engine overheating.
A butterfly in the header to switch between chambers would be worth looking at. Ages ago I drew something along these lines for Solex racing, with a rotating drum, switching between a short and a long header. I can't find the picture any more but it was not unlike the variable-length inlet system found nowadays on some Audis.

[TZ350]

Thanks for the ideas ..... :)

[wobbly]

In the testing I did using an ATAC chamber with a flat throttle plate close to the header gave just over 30% more power on top of the extra
we already had from the powervalve , at the bottom of the powerband.
I have operated them with a servo using a rotating throttle plate, or you can even use a Rotax type powervalve diaphram pulling a flat blade with a port in it.
This worked even better with its spring return and a small compressed air bottle to solenoid valve drive it with ECU control.

[TZ350]

Great, thanks for that....

[Drew]

Ummm, how do ya get an instantaneous transition from one pipe to the other? There's potential for a wicked dead spot at swap time, followed by a big power jump as the new pipe comes on.

How many cycles does it take for a smoker to come right after a miss? I think I remember Wob or someone saying ages ago, but I cant figure out how to search for it.

[Yow Ling]

Would switching to the cold pipe give an advantage as it would appear longer when switched over then as it heats up get shorter so kinda tracking the rpm , a bit like a power valve does , I guess after a wee while on the pipe this effect would start to decay but maybe of some benefit when exiting a slow part of the track

[Drew]

Would switching to the cold pipe give an advantage as it would appear longer when switched over then as it heats up get shorter so kinda tracking the rpm , a bit like a power valve does , I guess after a wee while on the pipe this effect would start to decay but maybe of some benefit when exiting a slow part of the track

Sooo, is it possible to just cool the pipe rapidly when the PV opens?

[Rick 52]

Hi there,

297908

the results of the 8th & final round of the 13/14 season of AMCC bucket racing from today are attached, Tim will be updating the website.

Congratulations to the winners:
F4 Rick Ford
F5 Tim Fraser
B grade Pete Leahy
C grade Helene Conway
Sidecars Rick & Henk

No Diproses this season, even though Nathanael did win the last 10 F4 races in a row… (out of 16 total)
I guess if I want to win anything I should stop falling off my mountain bike.
Regards,
David Diprose

Thanks to the ESE Team for your help and advice over the season, winning the Auckland championship is not easy and I am over the moon .

[peewee]

I have been working on a ZABEL 700 cc two-stroke single for sidecar-MX.

ive wondered about the zabel engines. is it one with the reeds in the crankcase and whats your thoughts on the engine as a whole from a engineering standpoint. does it look like it has alot of potential ? i thought about picking up a zabel if i see a used one for a decent price

[TZ350]

A butterfly in the header to switch between chambers would be worth looking at. Ages ago I drew something along these lines for Solex racing, with a rotating drum, switching between a short and a long header. I can't find the picture any more but it was not unlike the variable-length inlet system found nowadays on some Audis.

Audi variable-length inlet system.

297966

http://www.autozine.org/technical_school/engine/Intake_exhaust.html

[Frits Overmars]

ive wondered about the zabel engines. is it one with the reeds in the crankcase and whats your thoughts on the engine as a whole from a engineering standpoint. does it look like it has alot of potential ? i thought about picking up a zabel if i see a used one for a decent priceYes, it has case reeds. This version won quite a bit of world championship titles but from an engineering standpoint there are always unfulfilled wishes.
It's a short-stroke engine (100*89 mm) which is not favourable for a two-stroke, and the con rod might have been longer than the current 146 mm, but those mods would result in a larger engine, so all in all it ain't bad (as long as you don't have to kickstart it yourself.)

[husaberg]

Audi variable-length inlet system.



http://www.autozine.org/technical_school/engine/Intake_exhaust.html
Ages ago I posted one from a bike same idea only simpler........
it will take me ages to find it...........

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=266019&d=1341619864

3553 picures............

[speedpro]

Audi variable-length inlet system.

297966

http://www.autozine.org/technical_school/engine/Intake_exhaust.html

Interesting - splayed intake valves

[WilDun]

.
It's a short-stroke engine (100*89 mm) which is not favourable for a two-stroke,

I notice that two stroke competition engines usually have a 'square' bore and stroke (as opposed to chainsaws etc. which are usually very much 'oversquare') and I'm sure that there must be a very good reason for that, - what is it?

[Drew]

I notice that two stroke competition engines usually have a 'square' bore and stroke (as opposed to chainsaws etc. which are usually very much 'oversquare') and I'm sure that there must be a very good reason for that, - what is it?

Am I correct in guessing it's because they sit at max revs/full song non stop. So the crank takes less of a hammering with a shorter stroke?


Hmmm. So if I went cvt on a bucket sidecar, this would be a handy thing to remember...provided my guess is right. Hello 13,000rpm 100cc twin cylinder two stroke.

[speedpro]

- what is it?

Lots of things. As usual there's compromises to be made. It's explained earlier in this thread somewhere.

[TZ350]

Hmmm. So if I went cvt on a bucket sidecar, this would be a handy, 13,000rpm 100cc twin cylinder two stroke.

There are rumors, so if you wan't to be the first, you may have to be quick .... ;)

[wobbly]

In a competition engine square bore/stroke gives the best compromise between revability - dependant upon the stroke length,and the bore angle area available.
A short stroke bore with the same timings as a long stroke has less angle area available, and this limit on performance is not outweighed by the basic notion that rpm
makes power due simply to P= T*RPM/5252.
With less angle area available in a short stroke/big bore the torque cannot be held up sufficiently to use the rpm advantage.
Yamaha tried forever to use the 56 by 50.6 setup in GP racing and finally saw the light of 54 square dimensions, allowing Jaques to win the 250 title in around 2000
after years of hamstrung engines.

There is probably some merit in the idea that a short stroke saw engine can sit at peak rpm with less crank/rod loads, but I think most saws have been increased in size
over long periods, and the easy way for a factory is simply to bore it out.

[peewee]

In a competition engine square bore/stroke gives the best compromise between revability - dependant upon the stroke length,and the bore angle area available.
A short stroke bore with the same timings as a long stroke has less angle area available, and this limit on performance is not outweighed by the basic notion that rpm
makes power due simply to P= T*RPM/5252.
With less angle area available in a short stroke/big bore the torque cannot be held up sufficiently to use the rpm advantage.
Yamaha tried forever to use the 56 by 50.6 setup in GP racing and finally saw the light of 54 square dimensions, allowing Jaques to win the 250 title in around 2000
after years of hamstrung engines.

There is probably some merit in the idea that a short stroke saw engine can sit at peak rpm with less crank/rod loads, but I think most saws have been increased in size
over long periods, and the easy way for a factory is simply to bore it out.

ive been trying to understand angle area more. is it simply the amount of port area for every degree of crank rotation ? just for example can we say a short stroke engine has 1mm of port area for every 1 degree of crank rotaion and a long stroke engine might have 2mm of port area for every 1 degree of crank rotaion ? ive seen the term angle area used alot in books but never found a simplified explanation of what it is

[monkeyfumi]

Interesting - splayed intake valves

5V heads, 3 intake, 2 ex (just like Yamaha used to have)

[TerraRoot]

5 valve head i believe

edit, too slow :Oops:

[husaberg]

So they have 5v heads 5 cylinder engines and buggered er up the Logo at bit.

[Haufen]

I notice that two stroke competition engines usually have a 'square' bore and stroke (as opposed to chainsaws etc. which are usually very much 'oversquare') and I'm sure that there must be a very good reason for that, - what is it?

I can see a lot of win/win situations following each other in making a chainsaw engine oversquare.

I suppose one of the main reasons is vibrations and engine size. The latter is beneficial for a lower weight, too, which is very important for a hand held tool. Apart from that, the short stroke allows for low piston speeds and thus the usage of crappy oils while enabling high engine speeds. High engine speeds and a (relatively) big bore are beneficial to trapping efficiency in that high speeds provide less time for the mixture to escape the exhaust port unburned, and a big bore allows for a longer path the scavenging column has to travel inside the cylinder. This reduces fuel consumption and hydrocarbon emissions (which the latter is regulated by legislation). Running at a maximum BMEP of around 4 bar, there is no need to worry about insufficient angle area on these.

On the technical side, an even smaller displacement square engine would be interesting in terms of power to weight ratio, too, of course.

[WilDun]

Thanks for the answers on square bore and stroke and I'm sure all these questions have been addressed before somewhere in this forum but for a relative newcomer, finding these can be a bit of a mission, (but thanks to TZ for trying to make that easier).
While on the subject of chainsaws I was thinking that with the 'complete' cylinder barrelI/ head approach,this setup could possibly solve a lot of the problems associated with seperate cylinder heads. I realize it might make it difficult for experimenters etc. of course! but would it have any merit here at all?

Will.

[wobbly]

Yes the angle area issue only raises its ugly head when you are at the limits of power production for a particular engine size.
Unlike STA that takes time derived from rpm into account - angle area only describes exactly that, the area times the crank angle/displacement.
For a fixed displacement, as the bore increases the piston area increases as the square power of the diameter, but the wall area is only increasing by the bore times
a constant Pi.
Thus as we go further oversquare we increasingly loose available port area when multiplied by the correspondingly shorter stroke and its reduced piston sweep per degree
of crank rotation.
I think Frits has explained this better before somewhere.

[Frits Overmars]

For a fixed displacement, as the bore increases the piston area increases as the square power of the diameter, but the wall area is only increasing by the bore times a constant Pi. Thus as we go further oversquare we increasingly loose available port area when multiplied by the correspondingly shorter stroke and its reduced piston sweep per degree of crank rotation.
I think Frits has explained this better before somewhere.This is what I managed to find back:
An oversquare engine is not a good idea for a two-stroke; I will try to explain this with an exaggerated example.
Let us assume an engine with a bore and stroke of 40 mm.
Now we make the bore twice as big: 80 mm. That means that all ports can be twice as wide. But if we want to keep the cubic capacity the same, the stroke must be 10 mm instead of 40 mm. And that means that all ports will be ¼ as high.
So all port areas are halved, as are the rpms of maximum torque and maximum power. If we assume that the quality of the cylinder filling remains the same, the oversquare engine develops only half as much power as the square engine...

[WilDun]

This is what I managed to find back:

Guess that all explains why the Royal Enfield two stroke racer engine of the late sixties managed to hold it's own with its competition.
As I remember, it went against the flow by having a long stroke 'under square' engine (in those days everyone was beginning to favour short stroke for more revs). I should imagine that the conrod length would also play a big part here?

[TZ350]

298070 24mm inlet with boost bottle feeding the opening side of the inlet port just behind the RV so the returning pressure wave from the BB kick starts flow into the crankcase.

298071 On board generator for powering the Ignitec ignition and EFI system.

298073 New injector manifold to direct the fuel streams across the transfer ducts.

298074 There will be three 126 g/min injectors, with the middle one firing first then the outer ones come in when the engine gets up on the pipe. The center injector is angled up so as to cool the underside of the piston crown by squirting through a slot in the piston skirt. The outer two injectors are splayed out and down so they more properly spray horizontally across the transfer streams. Before, when they were square on to the barrel the outer two squirted at the back of the cylinder sleeve.

298076 Ball inlet valve and TPS.

After what seems like months of work the Beast is back on the dyno.

298075

It was pretty easy to start up so hopefully that is a good sign and I will be able to dial it in easily enough, then hopefully I will be able to run it on the track at the next Bucket meet at Mt Wellington.

There were three main objectives in using the EFI system. (1) Directly cool the underside of the piston by squirting fuel on it.

(2) To be able to more accurately control the fuel curve, especially in the area of over rev where a carburetor tends to go rich,

(3) Allow for a possible return to the plenum idea as the previous problem with it was fuel dropout building up in the bottom of the plenum and affecting the fueling making the engine run rich/lean at the wrong times, and leaving a lot of oil behind that should have found its way into the engine.

If I can make the plenum idea work then the poxy 24mm carburetor restriction will mean even less than it does now, which is sweet FA.

[F5 Dave]

And yet you'll scream and grizzle if anyone suggests a mm more oversize for the 100s.:whistle:

[TZ350]

<iframe width="560" height="315" src="//www.youtube.com/embed/Mxa3tuJ6Otw" frameborder="0" allowfullscreen></iframe>


And yet you'll scream and grizzle if anyone suggests a mm more oversize for the 100s.:whistle:

I have won my gains by hard work, not a rule change, but for the same reasons as the 100's I would like another mm too and have no problem with the 100's wanting theirs, so long as its the same deal for all the Bucket classes.

There is another thread devoted to thrashing out this issue.

[Frits Overmars]

298070 Matching the teeth orientation on the primary and clutch gears might give you another couple of horses:whistle:


The center injector is angled up so as to cool the underside of the piston crown by squirting through a slot in the piston skirt.The piston will appreciate it, but don't forget to cool the big end .



298076
If I can make the plenum idea work then the poxy 24mm carburetor restriction will mean even less than it does now.The bellmouth throttle allows you to make the inlet tract really short and then you don't need the boost bottle.
You can have a 38 mm (or thereabouts) entry to the inlet disk and a bellmouth with a 24 mm restriction at the plenum entry where the air flow can be almost continuous.

[TZ350]

Matching the teeth orientation on the primary and clutch gears might give you another couple of horses:whistle:

Good spotting, it turns out that a Chinese Honda clone has straight cut primary gears with the same center distance between them as my 125.


You can have a 38 mm (or thereabouts) entry to the inlet disk and a bellmouth with a 24 mm restriction at the plenum entry where the air flow can be almost continuous.

Yes, that was the original plan some 600 pages ago and I think the plenum is going to be worth another visit when I get the EFI thing working properly.

http://youtu.be/YxiEo8cgopg

http://youtu.be/p4ef-WUO1Qs

A couple of early clips of the magic vacuum cleaners 1st ever start up with the plenum.

[TZ350]

The plenum re visited ...


You can have a 38 mm (or thereabouts) entry to the inlet disk and a bellmouth with a 24 mm restriction at the plenum entry where the air flow can be almost continuous.

298098

Pretty much what we tried. The problem was, with the carb on the outside we got excessive fuel dropout in the plenum, EFI should cure that.


The bellmouth throttle allows you to make the inlet tract really short

298100 298099

With a real short inlet tract there were problems with resonance in the plenum at low RPM that I called the Blarrrs and that the motor could barely pull through and it needed a longer inlet tract to cure that.

298101 298102 298103

Then I tried an automated way of halving the area of the inlet tract at low RPM. This worked a treat and it was surprising how high the power curve would go before falling over (Blue line).

[TZ350]

Plenum Inlet Revisited ...

298104


The bellmouth throttle allows you to make the inlet tract really short. You can have a 38 mm (or thereabouts) entry to the inlet disk and a bellmouth with a 24 mm restriction at the plenum entry where the air flow can be almost continuous.

I think I can do this and make it work without increasing the inlet tract length by fitting a variation of the variable inlet tract idea behind the Bellmouth inlet. And having a stop that only allows the Bellmouth Inlet to open 50% until the revs are approaching maximum torque at which point the throttle will be able to be opened all the way.

298106

One of the things Thomas and I found when we were exploring ways to improve the flow through a 24mm carb, was that a big carb with a 24mm insert flowed much more air than a smaller one did, but any carb with an insert flowed better than a plain insert with a bellmouth entry did.

298107

We figured that a bigger carb with a 24mm insert acted like a flow straightener aligning the air column before it negotiated the 24mm restriction. But in practice the 38mm carb was to big and stalled the fuel flow when opened to quickly at lower rpm. A 28 or 30mm carb with a 24mm venture insert worked best on the Dyno and Track.

298105

If it does not have to meter fuel, the big carb with a 24mm insert could be worth a revisit for the inlet side to the plenum as it flows a lot of air and as it would not have to meter fuel it could be left fully open all the time.

Anyway for my plenum with a 38mm RV inlet to work I have to get the fuel injection idea going properly first.

Tomorrow ....... hopefully.

[jasonu]

298073 New injector manifold to direct the fuel streams across the transfer ducts.

298074 There will be three 126 g/min injectors, with the middle one firing first then the outer ones come in when the engine gets up on the pipe. The center injector is angled up so as to cool the underside of the piston crown by squirting through a slot in the piston skirt. The outer two injectors are splayed out and down so they more properly spray horizontally across the transfer streams. Before, when they were square on to the barrel the outer two squirted at the back of the cylinder sleeve.

298076 Ball inlet valve and TPS.

After what seems like months of work the Beast is back on the dyno.

298075

It was pretty easy to start up so hopefully that is a good sign and I will be able to dial it in easily enough, then hopefully I will be able to run it on the track at the next Bucket meet at Mt Wellington.

There were three main objectives in using the EFI system. (1) Directly cool the underside of the piston by squirting fuel on it.

(2) To be able to more accurately control the fuel curve, especially in the area of over rev where a carburetor tends to go rich,

(3) Allow for a possible return to the plenum idea as the previous problem with it was fuel dropout building up in the bottom of the plenum and affecting the fueling making the engine run rich/lean at the wrong times, and leaving a lot of oil behind that should have found its way into the engine.

If I can make the plenum idea work then the poxy 24mm carburetor restriction will mean even less than it does now, which is sweet FA.

It looks to me that the 24mm restrictor on the RV inlet will mean sweet FA because you have other injectors that feed into the transfer ducts that are not restricted in any way. Do all of these injectors combined flow meet the 'equivalent to a 24mm carb' rule and will you be able to prove it?

[Drew]

It looks to me that the 24mm restrictor on the RV inlet will mean sweet FA because you have other injectors that feed into the transfer ducts that are not restricted in any way. Do all of these injectors combined flow meet the 'equivalent to a 24mm carb' rule and will you be able to prove it?

Pretty confident no one is going to protest if he's running it too rich.

[Yow Ling]

Pretty confident no one is going to protest if he's running it too rich.

Why would it run rich ? it has plenty of air going through the 38mm inlet

[Drew]

Why would it run rich ? it has plenty of air going through the 38mm inlet

Still limited (turns out by fuck all) by the 24mm ball valve. Feeding it more gas doesn't change that.

[Ocean1]

We figured that a bigger carb with a 24mm insert acted like a flow straightener aligning the air column before it negotiated the 24mm restriction.

I vaguely recall test data related to output corrections to orifice plate based flow meters that showed that across a significant velocity/viscosity range an orifice plate returned lower overall pressure differential than a staged reduction in cross section. In other words a flat plate with a hole flowed better than an hourglass shaped restriction.

Put that together with the fact that a reduced bore gate valve usually flows better than a reduced bore ball valve at partial openings and the fact that you don't actually need a venture in your "carb" and you might have a case for experimenting with a thin flat gate slide over a thin 24mm orifice.

[Yow Ling]

Still limited (turns out by fuck all) by the 24mm ball valve. Feeding it more gas doesn't change that.

the ball valve is 38mm
the inlet to the plenum is 24mm
the disk valve is shut aprox 50%of the time
when the disk valve is open the inlet is 38mm
while the disk valve is closed the 24mm hole is constantly flowing
seems you chose the wrong 24mm orifice drew

[TZ350]

298120298118298119

Given up on the big carb idea, inlet tract becomes to long and its hard to package.

298115

but could this work? a 24mm carb feeding into a plenum chamber and the 34mm rotary valve inlet feeding directly from the chamber to the motor. That way when the motor takes a gulp (duration 200 deg) it sucks full atmospheric pressure through a high flow 34mm bell-mouth and the restrictive 24mm carb has much more time (duration 360 deg) to refill the plenum.


298116

The motor ran OK and it drove well on the track too.

http://youtu.be/YxiEo8cgopg

http://youtu.be/p4ef-WUO1Qs

It was fuel dropout building up in a big puddle in the bottom of the plenum and doubts about how much oil was actually finding its way into the motor that stopped the project and got us looking at EFI.

Also the realization that there was not as much of a power increase as expected for the increased inlet area and that pointed to restrictions somewhere else.

298117

So power dramatically improved when we increased the transfer port area by opening up the rear transfers. But its looking like the time is coming where another look at the plenum might be worth while.

I have elected to go the EFI way but a plenum arranged in such a way as to drain dropout fuel into the motor might work well, but its probably easier to fit something like that to a more conventional piston port engine than my RV carb on the side setup.

[TZ350]

I vaguely recall test data related to output corrections to orifice plate based flow meters that showed that across a significant velocity/viscosity range an orifice plate returned lower overall pressure differential than a staged reduction in cross section. In other words a flat plate with a hole flowed better than an hourglass shaped restriction.

Put that together with the fact that a reduced bore gate valve usually flows better than a reduced bore ball valve at partial openings and the fact that you don't actually need a venture in your "carb" and you might have a case for experimenting with a thin flat gate slide over a thin 24mm orifice.

Good idea, I have a copy of the old British Standards somewhere and now you mention it, I recall early mechanical fuel injection manifolds had a thin slide throttle plate.

298121298122

[husaberg]

Good idea, I have a copy of the old British Standards somewhere and now you mention it, I recall early mechanical fuel injection manifolds had a thin slide throttle plate.

So how come you are not using the slide throttle come variable timing Neil made up first? As it is much shorter than the ball valve.
<img src="http://i1056.photobucket.com/albums/t380/uniflow/0c93ef14.jpg" width="240px"/><img src="http://i1056.photobucket.com/albums/t380/uniflow/c0231e31.jpg" width="240px"/>
I will not accept to many variables ALREADY as an answer Rob;)

[TZ350]

That is on Neils F81M, and was for varying the closing point of the inlet valve. He is currently working on something similar which will be a fly by wire throttle. I am using the Ball Bellmouth throttle with TPS he made for me.

[Ocean1]

Good idea, I have a copy of the old British Standards somewhere and now you mention it, I recall early mechanical fuel injection manifolds had a thin slide throttle plate.

298121298122

Perfect. Be interested in any experimental results you might find.

[jasonu]

Still limited (turns out by fuck all) by the 24mm ball valve. Feeding it more gas doesn't change that.

My point is that only some of the fuel supply is restricted by the 24mm restrictor/carb/??? If you have another set of injectors outside of the 24mm restriction as prescribed in the rule book then surely that is outside of the rules.

[husaberg]

That is on Neils F81M, and was for varying the closing point of the inlet valve. He is currently working on something similar which will be a fly by wire throttle. I am using the Ball Bellmouth throttle with TPS he made for me.

It does both,........... add restrictor, hello throttle tps and 24mm intake in one ultra short package

[TZ350]

It does both,........... add restrictor hello throtal tps and 24mm intake in one ultra short package

But I want a short 38mm intake.

[F5 Dave]

My point is that only some of the fuel supply is restricted by the 24mm restrictor/carb/??? If you have another set of injectors outside of the 24mm restriction as prescribed in the rule book then surely that is outside of the rules.
Yes you are totally right. He should restrict the inlet by the flow size of the injectors too. 23.95 ought to do it.

[husaberg]

But I want a short 38mm intake.

So where is the intake restrictor going to be then?:confused:

HE GOES BACK AND LOOKS A PICTURE....
Then he laughs and says oh thats dubious. fiendish........
So an airbox feed by an 24mm "dummy carb" flowing just air..........mmmmmmmmmmmm.....

It was on PG100 Rob.

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=150925&stc=1&thumb=1&d=1258102202

[TZ350]

So an airbox feed by an 24mm "dummy carb" flowing just air..........mmmmmmmmmmmm.....

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=150925&stc=1&thumb=1&d=1258102202

Yes it used to flow air and fuel, and with EFI it will be the same equivalent amount of air, and the fuel gets added elsewhere.

298138

So ... Yep, an old 24mm carb is pretty much equivalent to a 24mm carb.

[Flettner]

You need one of these Rob,

http://i1056.photobucket.com/albums/t380/uniflow/c1d60c9b.jpg

I would machine a 24mm restrictor, totally smooth with no throttle piston at all, best air flow and absolutly legal! You might want to add some more volume up where the old aircleaner fitted, more volume is better, but who am I to tell you.

[Frits Overmars]

I have a copy of the old British Standards somewhere and now you mention it, I recall early mechanical fuel injection manifolds had a thin slide throttle plate.

298121298122The drawing on the right contains a written warning: it was designed by the Prince of Darkness :facepalm:.

[Frits Overmars]

It looks to me that the 24mm restrictor on the RV inlet will mean sweet FA because you have other injectors that feed into the transfer ducts that are not restricted in any way. Well, as long as these injectors don't inject air... I haven't got the bucket rulebook at hand but I imagine it stipulates (because that is how my rulebook describes it) that all oxygen used for combustion must come from ambient air and all this air must pass through restriction(s) with a total area equivalent to a 24 mm orifice.
Now if you would use the Orbital injection system, whereby fuel is pushed into the combustion chamber by means of pressurized air, that would be a different kettle of fish. My rulebook specifically allows the Orbital system because I want to promote fuel injection. Some smartass may start using a huge blower 'for this purpose' but we'll deal with that when it happens.

[Frits Overmars]

But I want a short 38mm intake.You can have both. You don't need to put the restrictor in the disk valve cover; you can use the plenum entrance for that, as Husabergs sketch shows.
I would machine a 24mm restrictor, totally smooth with no throttle piston at all, best air flow and absolutly legal! You might want to add some more volume up where the old aircleaner fitted, more volume is better.Way to go!

[TZ350]

OK had a play with the EFI on the dyno tonight. Sort of went OK, got the lower end to 8,000 rpm working OK but the old problems at the cross over point are back. At least now I know not to worry and with a bit of patience I will get it sorted.

The real problem is, is that I have no idea what the numbers mean or what a Alpha-N map for a 2T should look like and what worked before does not work now that I have a more symmetrical triple injector setup that points in the right directions.

298151 performance curves from an old Bridgestone motorcycle

I have been modeling my Alpha-N or TPS/RPM based map on the torque curve so it got richer as the torque and rpm increased. But the break specific fuel consumption drops off, so I am a bit confused.

298157 http://www3.telus.net/CarTunes/home/fuel injection operation.htm

""It is clear to see where peak torque is on the engine from the injection map, the large bump on the fuel map is at 6500RPM this is where cylinder filling is best and therefore is the point of maximum fuelling and maximum torque.""

More info on setting up an actual MegaSquirt system here:- http://www.extraefi.co.uk/MAP_Alpha_N.htm


"" One thing you have to always remember with alpha-N is that you don't actually know where the effective WOT is anymore (i.e., when you have enough throttle that opening it further doesn't affect the amount of air being ingested). At low RPM WOT could be only 20% throttle. ""

Hopefully get another crack at it tomorrow night.

[ken seeber]

Frrits, good to see you encouraging DI for 2 strokes

At Orbital, we initially started with a 3 cyl 1.2 litre engine and this first used a 30 cc compressor, but later went to a 36 cc, more for reasons of emissions rather than power chasing, these being of 2.5 & 3% of engine displacement. In this case, the compressor drew its air via the engine intake system.

When we did the 50 cc scooters, we used an eccentric on a crank wheel, essentially the full diameter of the wheel. This drove a small direct acting compressor piston (using a small roller against the eccentric) with a spring return. The piston was dia 25 mm * 5 mm stroke (well, pretty close to this...memory loss occurring here) equating to say 2.5 cc, around 5 %. In this case, the air for the compressor was ingested from the inside the crankcase, which was handy as, being oiled air, it both lubricated the compressor (and its bearing), plus the detergents in the oil assisted in keeping the injector clean.

Frits, you mention your rulebook. Is this the Freetech 50 regulations? I have looked and have been waiting for these to come out in English, but when translating, it doesn't seem to include the Unlimited class rules.

Thanks

Ken

[husaberg]

Well, as long as these injectors don't inject air... I haven't got the bucket rulebook at hand but I imagine it stipulates (because that is how my rulebook describes it) that all oxygen used for combustion must come from ambient air and all this air must pass through restriction(s) with a total area equivalent to a 24 mm orifice.
Now if you would use the Orbital injection system, whereby fuel is pushed into the combustion chamber by means of pressurized air, that would be a different kettle of fish. My rulebook specifically allows the Orbital system because I want to promote fuel injection. Some smartass may start using a huge blower 'for this purpose' but we'll deal with that when it happens.

The MNZ rules are pretty ambiguous
F4 2 stroke engines over 104cc are restricted to carburation equivalent to a single 24mm carburettor,

You can have both. You don't need to put the restrictor in the disk valve cover; you can use the plenum entrance for that, as Husabergs sketch shows.Way to go!
It was robs sketch from nearly 900 pages ago,
I am a bit confused so is the restrictor better at the air entry to the engine or at the plenum/air box entry. Frits?
I seem to remember Leon Moss selling spacers for some filters as part of the Ledar kits as the intakes were to short and the solid backed foam filters being allegedly esp problematic...
So I wonder if Robs Plenum based on a std GP outer case will suffer from having the solid wall to close to the intake, could this have contributed to the fuel drop out he suffered previously..........
What ever Rob does I think maybe some of that Russian rocket paint (ok house paint LOL) might be a good idea for the inside to stop the heat transfer from the cases to the intake............


The insulating capacity (http://www.emot.nl/specials.php)of this stuff is simply amazing !
The factory claims 1mm of paint equals 50mm of glasswool.
I did tests with a aluminium plate half covered with the coating on the coocking plate.
While the uncoated side is hot enough to bake an egg ,you can touch the coated side by hand !

And yes I am expecting commission from Martijn

[Frits Overmars]

Frits, you mention your rulebook. Is this the Freetech 50 regulations? I have looked and have been waiting for these to come out in English, but when translating, it doesn't seem to include the Unlimited class rules.Ken, I was referring to the rulebook for dutch mopedracing (www.sobw.nl (http://www.sobw.nl)). Freetech50 is just what it says; neither the limited nor the unlimited Freetech50 classes have any limit on carburation.
The Freetech rulebook contains a part dedicated to the limited class and a common part. There are no specific rules for the unlimited class; if you wish to build a 50 cc engine with four cylinders and fourteen speeds, be our guest!
The English version: I am still hoping someone with a decent grasp of English will step in and translate it. I simply can't find the time (spend too much of it on two-stroke forums :msn-wink:).

[Frits Overmars]

... is the restrictor better at the air entry to the engine or at the plenum/air box entry, Frits?The best you can do with a restrictor is to maintain a constant flow velocity all of the time. That means: a large plenum between it and the pulsating engine suction.


I think maybe some of that Russian rocket paint (ok house paint LOL) might be a good idea for the inside to stop the heat transfer from the cases to the intake.Certainly. And while you're at it, try to coat the insides of the crankcase and the transfer ducts.
Too bad this Russian stuff isn't fuel-resistant; you will have to coat the coating, which makes it a bit less easily applicable.

[TZ350]

298249

First move was to mark the flywheel at 15 deg BTDC.

298251

Then using a timing light, adjust the Ignetec's base advance so the 15 deg advance line, lines up with the mark on the flywheel.

298250

Started work on the fueling map, things are starting to come together, but probably making adjustments in to big a steps. More patience is required.

When I shut the throttle after a 12k pull the motor sounded like a hive of angry hornets, to lean on over run.

The big learn of the night was the truth of the quote below.

"" One thing you have to always remember with alpha-N is that you don't actually know where the effective WOT is any more (i.e., when you have enough throttle that opening it further doesn't affect the amount of air being ingested). At low RPM WOT could be only 20% throttle. ""

298253

I am still not sure if the torque curve is the ideal thing to follow because its just the air that's trapped, what about the air that is lost out the exhaust it must carry some fuel with it to so the fueling curve would need to be bigger than the torque curve in the areas the torque curve is lower???? Ie the fueling curve would need to be a higher flatter line than the torque curve is at lower rpm????

298254

Its interesting that at lower rpm and above 35% the torque curves nearly match each other,this must be where the effective WOT thing is happening well before the throttle is actually wide open.

[teriks]

OK had a play with the EFI....<snip>

I have been modeling my Alpha-N or TPS/RPM based map on the torque curve so it got richer as the torque and rpm increased. But the break specific fuel consumption drops off, so I am a bit confused.
Yup, fuel efficiency rises when everything is starting to work together..
Anyway, in case you have missed it, you can plot fuel flow in EngMod. Could give some decent clues of where to start.

[Haufen]

Certainly. And while you're at it, try to coat the insides of the crankcase and the transfer ducts.
Too bad this Russian stuff isn't fuel-resistant; you will have to coat the coating, which makes it a bit less easily applicable.

too bad, what about hot gearbox oil? Can it cope with that?


"" One thing you have to always remember with alpha-N is that you don't actually know where the effective WOT is any more (i.e., when you have enough throttle that opening it further doesn't affect the amount of air being ingested). At low RPM WOT could be only 20% throttle. ""

298253

I am still not sure if the torque curve is the ideal thing to follow because its just the air that's trapped, what about the air that is lost out the exhaust it must carry some fuel with it to so the fueling curve would need to be bigger than the torque curve in the areas the torque curve is lower???? Ie the fueling curve would need to be a higher flatter line than the torque curve is at lower rpm????

298254

Have a look at trapping efficiency to get an idea about the relative ratio between torque and fuel flow.

Did you not kind of auto-calibrate the FI using a lambda probe some time in the past? Sounds like a good idea to get a baseline calibration for the fuel map to me.


Yup, fuel efficiency rises when everything is starting to work together..
Anyway, in case you have missed it, you can plot fuel flow in EngMod. Could give some decent clues of where to start.

Do you know if that value includes the amount of fuel leaving the cylinder unburned?

[2T Institute]

The plenum re visited ...



298098

Pretty much what we tried. The problem was, with the carb on the outside we got excessive fuel dropout in the plenum, EFI should cure that.



298100 298099

With a real short inlet tract there were problems with resonance in the plenum at low RPM that I called the Blarrrs and that the motor could barely pull through and it needed a longer inlet tract to cure that.

298101 298102 298103

Then I tried an automated way of halving the area of the inlet tract at low RPM. This worked a treat and it was surprising how high the power curve would go before falling over (Blue line).

Have a look at a late model Ford Falcon engine they have a large variable length inlet that works by vaccum. A simple butterfly valve closes the long runner at 3800.

[TZ350]

Some definitions.

DELIVERY RATIO.
Mass of fresh charge supplied to the cylinder during scavenging divided by the mass of atmospheric air which would be contained in the swept volume ( not the trapped swept volume ) of the engine.


TRAPPING EFFICIENCY.
The ratio of mass of delivered charge which has been trapped to the total mass of delivered charge. Remember that some of the latter exits the exhaust port before combustion starts, ie during scavenging. This turns out to be approximately equal to the scavenging efficiency divided by the mass based scavenging ratio.

CHARGING EFFICIENCY.
The mass of fresh charge trapped in the cylinder during scavenging divided by the mass of atmospheric air which fill the entire cylinder volume when the piston is at Bottom Dead Centre. It is equal to the Trapping Efficiency times the mass based Scavenge Ratio ( nearly equal to the Scavenging Efficiency ).


BSFC. ( Brake Specific Fuel Consumption )
This is the fuel consumption in kg/kw-hours. If the engine has a power output of 5kw, a BSFC of 0.5kg/kw-hour, and runs for 10 hours, it will consume 5 x 0.5 x 10 = 25kg of fuel.


298281

Dratio Black line: DELIVERY RATIO
Ceff Green Line : CHARGING EFFICIENCY
Teff Red Line : TRAPPING EFFICIENCY
BSFC Blue Line : BSFC (Fuel Consumption)

298282

Ok this is where my thinking is at tonight, possibly wrong but there you are. So I am none to sure about how useful the BSFC would be as it looks more rpm and engine efficiency than load dependent.

But what interests me is the Delivery Ratio as I think this is the total volume of air that is passing through the motor and as we all know fuel and air needs to be mixed at a set ratio, even if some of it gets wasted out the exhaust.

298284

Now as you can see, not all the mixture that gets delivered actually stays in the cylinder long enough to be trapped there when the exhaust port closes. But with a carb all the "Delivered" air has had fuel mixed with it.

So that is my starting point, and the beauty of EFI is I can time the injection end point and reduce some of this wasted fuel, even better would be direct injection into the cylinder after the exhaust port is closed but that is another step for later.

298283

A series of throttle position Delivery curves simulated using EngMod2T.

Now all this air would normally have fuel mixed into it at a set ratio, so I am going to use these curves to develop my next Alpha-N fueling map. You can see the WOT point is about 45-50% of the real throttle opening up to about 8,000 rpm, so the map will have some flat areas on it.

[TZ350]

Ok, the map making went better but no matter how big the numbers I put in the map I could not get the thing rich enough to stop detonating at 10K plus rpm so I guess :scratch: the secondary injectors are not big enough. Have another look tomorrow night....

[speedpro]

Did the injector pulse widths top out at the rpm you were testing?

[teriks]

Do you know if that value includes the amount of fuel leaving the cylinder unburned?

I would _assume_ so.
The help files are rather short on the subject:
"Fuelflow The fuel flow in cc/min".
It can be found under Performance plots, you get a nice graph on fuel flow vs RPM.

[TZ350]

Did the injector pulse widths top out at the rpm you were testing?

Hard to watch the gauges and run the bike at the same time. I will check the fuel line pressure but yes I think your right, it is probably a timing thing.

This is how I understand it.

As a 2T has only half the time of a 4T to get things done, my 2T at 13,000 is equivalent to a 4t doing 26,000rpm.
298316 298315

The maximum time available to inject fuel is the time it takes to go through one revolution or 360 degrees less the time it takes to actually open the injector and get it fully flowing and the time to close it again and also a bit of down time so it does not over heat.

All of this open-squirt-close-rest has to be done in the time it takes to go through 360 degrees and at 12,000 rpm that is only 5ms and if you take out the open-close-rest time you only have 1ms left for full on squirt.

Every thing works OK at 8,000 rpm where the injector can be fully open and flowing for 3.5ms but there appears to be no where near enough fuel delivered with only 1.5ms available at 11,000 let alone only 0.6ms at 13,000.

Making the Alpha-N map numbers bigger only made things worse, I guess it brought the system into conflict with the time required for the injectors to be open compared to the time required for the injectors to actually open/close and have some down time.

[husaberg]

Hard to watch the gauges and run the bike at the same time. I will check the fuel line pressure but yes I think your right, it is probably a timing thing.

This is how I understand it.

As a 2T has only half the time of a 4T to get things done, my 2T at 13,000 is equivalent to a 4t doing 26,000rpm.

The maximum time available to inject fuel is the time it takes to go through one revolution or 360 degrees less the time it takes to actually open the injector and get it fully flowing and the time to close it again and also a bit of down time so it does not over heat.

All of this open-squirt-close-rest has to be done in the time it takes to go through 360 degrees and at 12,000 rpm that is only 5ms and if you take out the open-close-rest time you only have 1ms left for full on squirt.

Every thing works OK at 8,000 rpm where the injector can be fully open and flowing for 3.5ms but there appears to be no where near enough fuel delivered with only 1.5ms available at 11,000 let alone only 0.6ms at 13,000.

Making the Alpha-N map numbers bigger only made things worse, I guess it brought the system into conflict with the time required for the injectors to be open compared to the time required for the injectors to actually open/close and have some down time.

Remember the PSI Cagiva used (Later 180PSI)incidently what was the PSI Aprilia used Frits?

[Drew]

I'd fake it with ramped fuel pressure in the rail. Mind, mental maths (known for error more than accuracy) says you want to nearly triple the pressure if not more. Your injectors won't like that one little bit, even if your pump can handle it.

Hmmm, another two injectors squirting in from the front/sides?

Not an easy one to overcome without causing a whole new set of problems.

[Drew]

Remember the PSI Cagiva used (Later 180PSI)incidently what was the PSI Aprilia used Frits?There ya go, four times the pressure at least. Bloody hell, injectors to run at that sort of pressure would need to come from something modern and common rail direct...or a diesel.

[Yow Ling]

There ya go, four times the pressure at least. Bloody hell, injectors to run at that sort of pressure would need to come from something modern and common rail direct...or a diesel.

errrr car fuel injection is modern and common rail, the big advantage with modern diesel is the piezo injectors which are capable of up to 7 separate injection events per power stroke in a modern engine , although that can be done over a much longer time both before and after tdc to maintain pressure in the cylinder

[Drew]

errrr car fuel injection is modern and common rail, the big advantage with modern diesel is the piezo injectors which are capable of up to 7 separate injection events per power stroke in a modern engine , although that can be done over a much longer time both before and after tdc to maintain pressure in the cylinderCommon rail direct is what I was getting at there. Can't imagine there's a big upside to squirting fuel at that sort of pressure, at the back of a mostly closed valve.

[husaberg]

mmmmmm..of course Cagiva were throttle body injection though....
What pressure can Robs system handle and how many injectors? bigger ones I guess are progressively slower responding......
Neils link I guess is a lot more sophisticated but that comes at a price of course.....

[Drew]

mmmmmm..of course Cagiva were throttle body injection though....It really seems this is how Cagiva went about fixing the same issue, based on the fact that there can't be a great advantage in squirting high speed fuel at closed surfaces.

What pressure can Robs system handle and how many injectors? bigger ones I guess are progressively slower responding......
Neils link I guess is a lot more sophisticated but that comes at a price of course.....This was talked about earlier, but I still have no fucken clue on how to use the search function for this thread.

[husaberg]

It really seems this is how Cagiva went about fixing the same issue, based on the fact that there can't be a great advantage in squirting high speed fuel at closed surfaces.
This was talked about earlier, but I still have no fucken clue on how to use the search function for this thread.

search thread use a few words like psi injection pressure and results come up.
I often search by pictures relating to the posts using view thread images.
I did find this though, it's out of pitlane. I have posted it before. From memory both Robs and Neils was both about 40psi


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.