ESE's works engine tuner

[SwePatrick]

Dr Evil does it, a F4 class legal water cooled 110cc engine.

Attachment 324038 ...... Attachment 324040

Finally, after several weeks of detailed finishing work the Frankenstein Mr Bigglesworth engine is ready.

Possibly the worlds first ever 1979 learner/commuter Suzuki GP100 engine fitted with EFI, digital ignition, a dry sump six speed gear box conversion, an oversize KE 175 rotary valve, a servo power valve and water cooling.

Attachment 324039

All that remains is to fit it into the frame. Being 12mm wider than the original five speed air cooled unit and needing a radiator, pump and associated plumbing, it is not a straight swap but hopefully I will get it all done this week.

Nice!

Next weekend will be first shakedown for my new engine(the downstroked kx250)
I feel that the gearing is a bit wrong, but maybe it´s me being heavy.
I´ve got a driver that is half my weight, hoping that will solve the problem
However, the engine seems crisp and sound.
It revves like a 85cc mx bike

[peewee]

hey guys ive started the drawings for the outer wall templates like what I did on the inner walls. tomorrow I can transfer these to thin alum and start grinding. since the entrance is so small (ive done everything I can short of splitting the cases and welding the gasket surface wider) this is how they'll have to be shaped but there is still a small amount of converging as the passage goes up. in the end it should be far better than the original passages

[TZ350]

Nice!

Next weekend will be first shakedown for my new engine(the downstroked kx250), the engine seems crisp and sound.
It revves like a 85cc mx bike

Thanks, and I look forward to some videos of the KX if you get to take a few.

hey guys ive started the drawings for the outer wall templates like what I did on the inner walls. tomorrow I can transfer these to thin alum and start grinding.

A great way of doing it, there are lots of interesting projects being worked on by people, I love it.

[Frits Overmars]

hey guys ive started the drawings for the outer wall templates like what I did on the inner walls. tomorrow I can transfer these to thin alum and start grinding. since the entrance is so small (ive done everything I can short of splitting the cases and welding the gasket surface wider) this is how they'll have to be shaped but there is still a small amount of converging as the passage goes up. in the end it should be far better than the original passages

Hi Peewee, I see you've chosen different center point coordinates for the inner and outer radii. In order to achieve still more conversion you might try to move those centers even farther apart, like in this duct geometry of the Aprilia RSA125 A-transfer.

[F5 Dave]

Should be interesting Rob. But I'd suggest you raise the seat so a human being can ride the bike. Well a European one over the age of twelve.

[Peter1962]

No worries Dutch, you missed nothing because there was nothing here to miss. I was never at liberty to post Roland's results; I only whispered in Wobbly's ear.

Frits, did the experiment at Modena let them draw conclusions or is the experiment still proceeding ? Do you forsee a practical use for this device in the future of 2 stroke competion engines ? Or is the rotary valve still the winning formula when ultimate power and a wide powerband + overrev is the goal ?

[Frits Overmars]

Frits, did the experiment at Modena let them draw conclusions or is the experiment still proceeding ? Do you forsee a practical use for this device in the future of 2 stroke competion engines ? Or is the rotary valve still the winning formula when ultimate power and a wide powerband + overrev is the goal ?

Conclusions? Hell yes: 10% power gain and far better overrev.
Still proceeding? I doubt it. Like Wobbly said, there's no way that the CIK (the international karting governing body) will permit anything breaking new ground. Old farts, the lot of 'm.
Do I foresee a practical use? I would have to, wouldn't I? It's my 24/7-idea.

[peewee]

Hi Peewee, I see you've chosen different center point coordinates for the inner and outer radii. In order to achieve still more conversion you might try to move those centers even farther apart, like in this duct geometry of the Aprilia RSA125 A-transfer.

frits im not sure what you meen by different center point coordinates but my passages cant be like the rsa because of the small passage entrance, which is dictated by the mating surface of the crankcase. ill get a photo so you can see the problem

the only easy thing I could of done was raise the bottom of the inner wall, where the bullnose corner is typically located. this may have allowed a more converging passage.

[Peter1962]

Conclusions? Hell yes: 10% power gain and far better overrev.
Still proceeding? I doubt it. Like Wobbly said, there's no way that the CIK (the international karting governing body) will permit anything breaking new ground. Old farts, the lot of 'm.
Do I foresee a practical use? I would have to, wouldn't I? It's my 24/7-idea.

Frits, there is 1 (one...) manufacturer that is still investing in 2 stroke technology, related to motorbikes : KTM. If this experiment gave proof of concept of the 24/7 induction principle, would this not be a great platform to build your device as an aftermarket solution ?
The number of 2 stroke MX and enduro bikes sold per year are in the thousands, this market is 10 times the total karting engine market. And it is the only 2 stroke competion where there are no retarded rules that inhibits all possible progress.
I do not know if Modena is active in other branches than karting, but with a sanctioning body like CIK we can forget all evolution in that particular branche of sport. Maybe a manufacturer like TM who are active in MX and enduro also would be interested ?

I mean, when was the last time that any manufacturer had an idea that gave their MX 250 cc a 10% gain in power, and gave a solution to the limiting factor of actual 2 stroke MX engines when compared to 250 4 strokes : too little overrev ?

[wobbly]

Peter, I agree that KTM ( and TM as well ) may be a viable end use for the 24/7 concept as they do build MX bikes, but the lack of " overev " in the 250 - 2T is limited by the
crank, not any particular tuning element like the reeds.
The 4T engines are very oversquare, and will rev to the moon with the pressure lubed big end - then it destroys a number of engine parts worth more than the whole bike to replace.
In the 2T the pipe/ports/undersquare crank are designed specifically to give a wide useable powerband that then drops off violently to prevent
sticking the needle roller big end thru the case.
The 72mm stroke used in all 250 - 2Ts will rev to 11,000 with a very limited race life.
The MX bike engines are all severely power limited past 10,000 to give an acceptable service interval.

[Peter1962]

Peter, I agree that KTM ( and TM as well ) may be a viable end use for the 24/7 concept as they do build MX bikes, but the lack of " overev " in the 250 - 2T is limited by the
crank, not any particular tuning element like the reeds.
The 4T engines are very oversquare, and will rev to the moon with the pressure lubed big end - then it destroys a number of engine parts worth more than the whole bike to replace.
In the 2T the pipe/ports/undersquare crank are designed specifically to give a wide useable powerband that then drops off violently to prevent
sticking the needle roller big end thru the case.
The 72mm stroke used in all 250 - 2Ts will rev to 11,000 with a very limited race life.
The MX bike engines are all severely power limited past 10,000 to give an acceptable service interval.

Wobbly, when tuning an MX 250 engine, is it possible to use better quality bearings so that the 10.000 rpm limit can be breached in a more safe way ? Or is it the crank itself that can not support these rpm's for a longer period ? When you are working with a ktm engine for kart use, do you retain the original crank ?

[wobbly]

The bearings used these days in 2T - MX cranks are all flat construction , silver plated cages, so the quality isnt the issue.
Its the inertial loads of stress reversal at BDC and TDC, and the inability of the cage to accelerate fast enough to prevent skidding ( instead of rolling )
by the needles.
Pressure fed, shell bearings, as used in a 4T dont have these issues, and the bottom ends are pretty bullet proof.
As I said, by giving up service life, the 72mm cranks can be spun to 11,000, but be prepared to change the big end VERY regularly.
I have changed just the cage/needles on a KZ2 crank 4 times with no issues as the rod and pin dont wear at all.
Its the cage scuffing that causes failures, no matter how much, or how good the oil used.

Gas Gas 250 engines used in kart road racing are 68mm square, and they are bullet proof at 11.000 - the normal MX crank are severely marginal.

[shnaggs]

The bearings used these days in 2T - MX cranks are all flat construction , silver plated cages, so the quality isnt the issue.
Its the inertial loads of stress reversal at BDC and TDC, and the inability of the cage to accelerate fast enough to prevent skidding ( instead of rolling )
by the needles.
Pressure fed, shell bearings, as used in a 4T dont have these issues, and the bottom ends are pretty bullet proof.
As I said, by giving up service life, the 72mm cranks can be spun to 11,000, but be prepared to change the big end VERY regularly.
I have changed just the cage/needles on a KZ2 crank 4 times with no issues as the rod and pin dont wear at all.
Its the cage scuffing that causes failures, no matter how much, or how good the oil used.

Gas Gas 250 engines used in kart road racing are 68mm square, and they are bullet proof at 11.000 - the normal MX crank are severely marginal.

Ski-doo's new 850 etec has pressure fed shell bearings.
Maybe this will trickle down to the MX world? Wishful thinking.

If the crank is the issue to the MX 250's rev limit, then can we tune the engine to produce more low-end, so the spread of power is more but just the other way, plus not have the over rev hit a brick wall?

I've seen the trombone pipe, but I have been thinking of another way to make a variable length pipe, but simplified. Will it work? Have no bloody idea...but it's fun to think about.

[shnaggs]

I have just completed a huge number of sims for the KZ10 with all manner of different reed blocks, the only way to get a meaningful result was to set the petal thickness for every block
such that the 1st harmonic rpm was 10,000 with engines natural peak power at 13200 ( as in reality ).
This then shows the real effect of the reed block geometry on the power - not the differences due to the varying petal thickness - as this is easily changed during the subsequent dyno confirmation process.

How did you come up the 10,000 harmonic rpm? Was that just the natural freq of the stock reeds, or was this an ideal freq that you determined?

[wobbly]

As I said before, if the reeds are too thin they loose control at peak rpm.
The KZ2 engines will run happily to 15000, and peak power is at 13,000 or so.
In the sim if I went 0.01mm thinner than 0.45 petal thickness on the stock cage ( the petals are actually 0.35,but have backups on top as well )
the power would drop dramatically past 14,000, where the tip lift started to go very weird.
When simming the Blaster/Banshee VF4 the petals needed to be at 0.3mm, and in both cases the 1st harmonic was at 11,000.
Sorry i said 10,000 before ( just checked ).
With the 1st harmonic set at 11,000 ( same case with the Boyesen asymmetric cage I simmed as well ) the petals were stable up to 15,000 when simming at that rpm.
So - run the reeds as thin as you can,with the thickness set by keeping tip lift under control at the peak rpm you will use when running.
And this will give you the best power at the lowest and highest rpms.
Reeds are a hugely complex area of tuning - and to write workable code for, as thin petals, by themselves are useless.
They flutter and go spastic very easily and you end up with big power losses and chipped tips in no time.
But with combinations of backup stiffness/length/shape and the use of rev plates, huge gains in power are just one more dyno run away ( he says after doing 3 days non stop
testing just that on SKUSA Honda CR125 ).