ESE's works engine tuner

[richban]

Im not forgetting the rider at all there Rick, just continuing the idea that less is more as far as power goes. I really was certain that the bike Avalon was riding had 24HP, but it goes to show that the race wins for ESE have all come on the shoulders of the lower side of the maximum power, and as a result gained rideabilty.

Am I correct in saying the fast 4T engines have around 24 HP at around 11,000 RPM?

24 at 12500. At the moment.

[SS90]

[/I]

24 at 12500. At the moment.

That is quite easy to achieve (actually beat considerably) from an air cooled 125 2T with open carb size... And given that it has been well proven that the 24 carb "restriction" is moot, There is no reason why it can't be pushed further, and from a lower rpm ceiling, and perhaps building a long fat peak power curve to say..... 11,500rpm.

[wobbly]

I dont get it at all.
Its been well proven and done for years with 125 engines - they are race reliable spinning to 14,000 all day.
Air cooled is irrelevant, old engine is irrelevant, the modern flat big end cage geometry is what makes it work with a 54mm stroke.
It is EASYER to make good power at higher rpm.
Remember Hp = Tq * RPM - so instead of going to 11500, spin it to 13500 and that equals a power increase of 2000/11500 = 17% if the
elements are designed to hold up the torque at that rpm..
And the sonic wave activity is stronger at higher rpm so getting an achievable, reasonably high bmep is, again, EASYER to achieve at higher rpm.
Having a 5000 rpm wide useable powerband from 8500 to 13500 is in fact alot EASYER to build, than having to design for a much higher bmep, to achieve the same power from 6500 to 11500.
Race reliability has NOTHING to do with the power being made, and in this case, NOTHING to do with the rpm being used, as both numbers are WELL within the limits of todays technology.

[richban]

[/I]

That is quite easy to achieve (actually beat considerably) from an air cooled 125 2T with open carb size...

Really! no shit. Well who would have thought that. Can you tell me how to build a 30hp 4 stroke please. Ta.

[speedpro]

SS90 is talking about a 2T Rich, NOT a 4T.

I don't think anybody is going to make rash claims about being able to beat your achievements regarding power from a 150cc(?) 4T with the technology we're using.

[F5 Dave]

Taumarunui 2

Attachment 275870

Water cooled TF100 CrazyMan 2T ???? rwhp ... 82kg

Attachment 275873

Kobas MC18 framed MB100 special rwhp??? ... 89kg

Attachment 275871

FarmerKen's MC18 TF125 rwhp???? but fast ... 85kg

Attachment 275872

Regans 24 rwhp FXR150 special ... 84kg

Attachment 275869

Rick52's 21 rwhp RS TF125 special ... 75kg

Attachment 275868

The Beast 27 rwhp 3LN FZR Suzuki GP125 ... weight ??????

My RG50 while it was still in the Rg frame. . . 59.5kg (was same on those scales up there too).
So how do you feel now?

Actually got slightly heavier in the RS chassis.

[TZ350]

My RG50 while it was still in the Rg frame. . . 59.5kg So how do you feel now?

.......... ... plump

[TZ350]

Jasons new bucket RS125 frame with CBR150 motor 22HP and 78 kg we hope?

RMS Eng has always talked about power and weight, and emphasized the light weight of his bikes.

Its not just about reliable hp and rideability of the bike, there is another essential piece to the jigsaw that TeeZee and more so RMSEng have been talking about.

Yes that's right ... RMS Eng has consistently talked about the importance of making a light bike and I am now totaly convinced he is right.



Rick plus Bike is about 145 kg all up and that works out at 7kg/hp power to weight ratio, Av and her bike are lighter with more hp.



Tim and the Beast (which is much heavier) work out to be much the same as the better 4-Strokes and so there is the answer to why the Beast was not leaping away from them like you would expect from a high 20's hp bike.

I was a bit indifferent before but after watching the bike at Tokoroa and Taumarunui I have become convinced that losing weight is as important as making the hp and power spread that I want.



I have a MC16 frame and could lose a lot of weight by making something new like FarmerKens MC18/TF125 special.

RMS Eng was on to it.

[TZ350]

Following the less is more principle for race winning power and reliability, Chambers is going for the old school approach.

[TZ350]

My super performance CVT bits turned up today, all in plain brown box's with none of the naughty words so everything is totally legal. I have found I can get an even shorter belt so everything will certainly fit in the chassis space available.

For anyone confused about this, the design plan is a solid 6,000 rpm power spread (or CVT equivalent) that equals the FXR's and more power every where for better top speed and punch out of the corners than the best of the 4-Strokes can manage.

Now I am working on three approaches to this.

(1) Improve the 4,000 rpm spread I already have with an ATAC valve and other cunning trickery.

(2) Trombone pipe.

(3) CVT.

So there is three engine development plans on the go at once, and a new 15kg lighter better handling rolling chassis being built for it too.

[jasonu]

RMS Eng has always talked about power and weight, and emphasized the light weight of his bikes.



Yes that's right ... RMS Eng has consistently talked about the importance of making a light bike and I am now totaly convinced he is right.


RMS Eng was on to it.

I thought it was obvious.

[cotswold]

Had to try mine for porkie-ness and by putting it in gear and standing it upright on the bathroom scales she came to a bit of a podgie 83.6kg.. this includes about 2ltrs fuel. (Old photo of the bike so all the bits that aren't on the photo are on the bike.)

Actually after checking the list it's not too bad, plus I machined many grams out of the new yet to fit go faster cases.

[TZ350]

Had to try mine for porkie-ness and by putting it in gear and standing it upright on the bathroom scales she came to a bit of a podgie 83.6kg.. this includes about 2ltrs fuel.

Thats 18kg lighter than the Beast ......

[TZ350]

B9 plug after Tokoroa.

The spark plug - why are you running a 9 in a Super Hot air cooled engine that is always going to be running up against the fins thermal ability to reject heat fast enough.
A KT100 making 18 Hp with more finning than you have will tolerate a 9 plug - just.
That is the reason there is no distinct burn line on the porcelain - as ALL of the porcelain is running too hot for an oil zone to form, and give you a reading.
I would be fitting a 10.5 - this is what the 28 Hp, 22,000 rpm 100cc air cooled kart engines HAVE to run or they seize instantly.The end of the earth electrode is blasted clean - that is heat induced deto, or as I said at the beginning, maybe this is causing pre - ignition.

B10 plug after Taumarunui

(2) B10H plug and an extra 4 deg auto retard on top of the TPS retard map did not cure the deto, so probably not an ignition timing or plug thing.

The B10 plug from Taumarunui after some hot laps and a proper plug chop before over rev deto set in. I would be interested in what Wob has to say about it.

(3) Deto in over rev, may mean, not enough blowdown time area for those rpm, Jan, Frits and Wob have talked about that.

(4) I might have to look at some way of automatically dumping pressure out of the expansion chamber when detoing in over rev.

Quite a bit on page 600 too.

Kel sent me this ......

jan thiel on part throttle deto

"I am 100% convinced our engine could have run for 6 hours at max power without seizing.
The problems arise when you close the throttle, or run part throttle!
The piston is mainly cooled by the transfer flow.
And at part throttle there is less transfer flow, causing detonation (auto ignition)
The entering fresh charge is ignited by the remaining, hot, burned gases!
You can see very severe damage to the piston after maybe 10 seconds at 20% throttle.
This still is an unresolved problem! I was thinking about a way to reduce engine power without closing the throttle. But how can you do this? I did not find a solution before I retired.
And nobody else was really interested.
At 100% throttle the engine was undestructible!
By making the transfer ports as wide as possible we had very good piston cooling."

No answer here but at least we are not alone with engines that fail on part throttle

I scraped the full coversation below from here:- http://www.pit-lane.biz/t3173p60-gp1...vermars-part-2

Brian Callahan
Jan or others, how did you control the tuned pipe wall temperature (or EGT directly?) when testing on dyno? This seemed the most difficult thing to mimic when testing either the GP engines at QUB or my R/C boat engines, in the lab. The inertial dyno or computer controlled brake seem to work best because we can match the test engine's acceleration with reality. On steady-state testing, EGT would simply climb 500, 600, 700, 750 °C until way past reality and the piston would seize.

Frits Overmars
This has always been one of Jan's greatest handicaps. He has asked for an inertial test bench over and over, but Aprilias race director Witteveen, or The Great Leader as we call him, never deemed it necessary....

Jan Thiel
When EGT goes up and up there should be some serious problem with the engine.
We never had pistons seize during our steady state tests.
Working on the dyno continuously 5 days a week!
I am 100% convinced our engine could have run for 6 hours at max power without seizing.
The problems arise when you close the throttle, or run part throttle!
The piston is mainly cooled by the transfer flow.
And at part throttle there is less transfer flow, causing detonation (auto ignition)
The entering fresh charge is ignited by the remaining, hot, burned gases!
You can see very severe damage to the piston after maybe 10 seconds at 20% throttle.
This still is an unresolved problem! I was thinking about a way to reduce engine power without closing the throttle. But how can you do this? I did not find a solution before I retired.
And nobody else was really interested.
At 100% throttle the engine was undestructible!
By making the transfer ports as wide as possible we had very good piston cooling.

As Frits has written, I would have liked to have also a dynamic testing possibility, with a flywheel.
In my opinion you should simulate a straight, starting at around 10.000 rpm, and shift through the gears
until you reach top speed. And with the airbox as used on the bike, with a ventilator that simulates the raising
air speed as it would be on track! Maybe it is interesting to know that without a ventilator the engine gave
less power with the airbox fitted.

I was told that such a testing system was too expensive.
And unnecessary as we won anyway!

I can also see a disadvantage of 'dynamic' testing.
Because the duration of the test is so short you can get away with very extreme (too extreme?) settings,
without damage.

GrahamB
Remember that retarding the ignition is used at high rpm to increase exhaust temps and effectively shorten the pipe. So it's likely to increase the heating of the front edge of the piston...

Haufen
Yes I know, but part load egt is usually lower than full load egt. And I think most of us would prefer higher part load egt over part load detonation. Of course, how far one could go and how far one would need to go would have to be tested, and how much would be needed would depend on the engine.

Mic
How about much larger travel on the exhaust power valve.
With a shorter exhaust port duration power is lower. And this is already controlled with the stepmotor over the ECU.

Jan Thiel
This causes detonation (auto ignition)
The problem is that the burned gases do not exit the cilinder!
Retarding ignition also does not make sense.
As you have an AUTO-inition problem!
So the engine does not 'listen' to its ECU anymore!
What you would need is the same fresh gas flow, but with less HP!
Not easy to achieve!
A variable tailpipe might help.

Jan Thiel
Haufen, We also had such a test bench at Aprlia.
The prototype of this test bench was developed by Apicom in collaboration wit Aprilia.
So we had it first, and now anyone can buy it.
It was helpful but not what I wanted.
A so-called step test.
And without the airbox!

Frits Overmars
Like Jan wrote, a shorter exhaust duration will worsen the detonation. What happens is this:
During normal operation, the blowdown time.area of the exhaust ports is sufficient to drop the cylinder pressure below the crankcase pressure before the transfer ports open, even at high rpm.
At part-throttle that cylinder pressure will drop to the same level, but now the crankcase pressure is much lower and exhaust gases will enter the transfer ducts, contaminating and heating the fresh mixture even before it enters the cylinder.
A theoretical solution would be a power valve that enlarges the normal exhaust timing instead of lowering it. But that is impractical as it would ruin the shape of the exhaust duct and it would cause cooling problems in the cylinder's exhaust area.
A variable tailpipe area, like Jan says, can be a more practical approach. I designed a simple solution, shown in the drawing below, but then two-stroke development at Aprilia was terminated because of Dorna's ban on two-strokes

Howard Gifford
Another way to lower HP without sacrificing piston cooling would be to richen the mixture when you want to lower the power. With a signal to a fuel enrichening solenoid you could achieve a power range. It would then be instantaneous and programmable. Not enviornmentally friendly but would work for racing. The mixture ratio difference from high power to low power would need to be just rich enough before a misfire and just lean enough for sustained high power.

The variable tailpipe idea will work but I suspect the pipe temperature would drop off and it would take several seconds to regain full power. But then again rich mixture may have the same problem.
Two strokes are like redheads. Hard to figure out and very temperamental. But when they are happy they are a lot of fun!
HG

Jan Thiel a écrit:
The entering fresh charge is ignited by the remaining, hot, burned gases!
You can see very severe damage to the piston after maybe 10 seconds at 20% throttle.
This still is an unresolved problem! I was thinking about a way to reduce engine power without closing the throttle. But how can you do this? I did not find a solution before I retired.
And nobody else was really interested.

Institute of TwoStrokes
On aftermarket ignitions I use there is a mode I can switch on where a number of indivdual sparks are cut, depending on throttle position. It is now only configured for cutting 1 in every 3 sparks on over run(tps <10% with high rpm). Would that sort of system solve the part throttle detonation? If the number of sparks cut could be varied along with TPS for this to begin and end? If it would be helpful I'm certain the manufacturer would only need a software change to do this.

Jan Thiel
I certainly thought about cutting sparks.
But remember: the problem was AUTO-ignition!

GrahamB a écrit:
Remember that retarding the ignition is used at high rpm to increase exhaust temps and effectively shorten the pipe. So it's likely to increase the heating of the front edge of the piston...

Jan Thiel
Indeed, retarding too much caused detonation!

Institute of TwoStrokes a écrit:
Jan Thiel a écrit: The entering fresh charge is ignited by the remaining, hot, burned gases! You can see very severe damage to the piston after maybe 10 seconds at 20% throttle.
This still is an unresolved problem! I was thinking about a way to reduce engine power without closing the throttle. But how can you do this? On aftermarket ignitions I use there is a mode I can switch on where a number of individual sparks are cut, depending on throttle position. Would that sort of system solve the part throttle detonation?

Frits Overmars
As Jan pointed out, once you have auto-ignition, the engine does not listen to its ECU any more. So you would have to start skipping sparks well before the onset of detonation.
In a foul-stroke your proposed system does work, but a two-stroke would react far from linear. For example, if you skip 1 in 4 sparks, you will loose much more than 25% of engine power because that one missing spark will cause the gasdynamics processes to collapse. The main problem would be to realise a smooth transition from intermittent to full ignition.


Jan Thiel a écrit:
Retarding ignition also does not make sense.
As you have an AUTO-inition problem!
So the engine does not 'listen' to its ECU anymore!
What you would need is the same fresh gas flow, but with less HP!
Not easy to achieve!
A variable tailpipe might help.

Haufen
I think I expressed myself unclearly. What I meant was the following:
Imagine your engine with the throttle opened just above the auto-ignition range. Then you have sufficient transfer flow, but too much power. To lower the power, now retard the ignition. Then you still have sufficient transfer flow, but with less power.

I think Honda used auto-ignition to their advantage on two-strokes. As far as I remember they did it with a (very) variable exhaust power valve.

Frits Overmars a écrit:

Mic a écrit:
How about much larger travel on the exhaust power valve. With a shorter exhaust port duration power is lower. And this is already controlled with the stepmotor over the ECU.

Frits Overmars a écrit:
Like Jan wrote, a shorter exhaust duration will worsen the detonation. What happens is this:
During normal operation, the blowdown time.area of the exhaust ports is sufficient to drop the cylinder pressure below the crankcase pressure before the transfer ports open, even at high rpm.
At part-throttle that cylinder pressure will drop to the same level, but now the crankcase pressure is much lower and exhaust gases will enter the transfer ducts, contaminating and heating the fresh mixture even before it enters the cylinder.
A theoretical solution would be a power valve that enlarges the normal exhaust timing instead of lowering it. But that is impractical as it would ruin the shape of the exhaust duct and it would cause cooling problems in the cylinder's exhaust area.
A variable tailpipe area, like Jan says, can be a more practical approach. I designed a simple solution, shown in the drawing below.

Attachment 269228

Haufen
I think I have not gotten behind the variable tailpipe idea, yet. What would you like to vary with it and to achieve which effects? At little throttle openings the pressure inside the exhaust pipe is already very close to atmospheric pressure (if not even) on most engines. And if you had say 100mbar inside the pipe at the critical throttle opening, then the engine might have had more power with a bigger tailpipe.

Attachment 269228

Frits Overmars
'Opening' the end of the reflector will cause a substantial weakening of the reflected pulse and thus less charging of the cylinder. Izze simple, no?

Haufen a écrit:
Variable transfer timing would be nice also, if feasible.

Frits Overmars
That would be my ideal. Lowering all the transfer roofs would shorten the transfer timing and lengthen the blowdown timing, so the cylinder pressure would drop further before the transfers would open. It would cure the hig revs/low power-detonation and it would improve the power band because a too early-returning exhaust pulse would have less opportunity to push the fresh cylinder contents back into the crankcase.
A controllable transfer height would even make a throttle valve unnecessary.
There's only the little problem of how to build it...

Jan Thiel
Haufen, Auto-ignition usually occurs between 10 to 40% throttle at high revs.
In fast, non full throttle corners.

Retarding the ignition was tried to diminish power.
This makes the exhaust very hot.
Then, when you need full power, it is not there because the exhaust temperatures are wrong.
This takes a little time, when the engine is back to full power you are already at the end of the straight!
The same goes for water injection in the exhaust.
It was tried by Rotax about 25 years ago.
There was a LOT more power at low revs, so the rider had to take it easy when opening the throttle.
But the engine revved a little bit less, because the exhaust temperature did not recover at high revs.
And lap times became actually slower.
After a day of testing the system was switched off.
Lap times immediately improved!

A very important thing when accelerating is the power you have after changing gear.
Spark interruption may be not so good for this!
As I did not have the dyno I wanted this gearchange effect could not be tried on the dyno, very regrettably!
Retarding the ignition and weakening the mixture by powerjet can also have a negative effect on this.
The exhaust temperature should be 'Right' for the No. of revs after you change gear.
If the temperature is too high there will be less power!
So it is REALLY complicated!

[cotswold]

Thats 18kg lighter than the Beast ......

Thats quite a lot of pies