ESE's works engine tuner

[SwePatrick]

If you simply keep winding in advance and it keeps making more power every time , then it was way retarded to start with or the compression is too low - what is it ?
And something is seriously wrong if it looses power on Methanol " because its getting hot " when doing a back to back . That should never , ever be an issue on jungle juice.
You should be able to do 3 back to backs at a minimum with no power loss - again something is very wrong and it needs addressing.
One of the most important lessons I learnt from Jan was using EGT to get the tune dead the same every dyno run,
You need to find and settle on a specific egt the run ends on for every tune change - be it reed petals or ignition advance as the Exhaust temp in many cases has way more influence
than the change you did has.

You´re welcome to come sort it out, pm for adress! =)
It would be quite cool the instead read some positive text from you.

Well think of this:
It must not be the 'powerproducing' things that are making it loose power when hot(cylinders, carburetors, pipe, reeds, etc etc)
There are more things, that huge tire for an example, a rubber belt that might slip ever so slightly, and so on....(this stresses out the transmission parts a LOT, it´s made for about 20-25hp)
I need to dyno it with somewhat 'cold' engine/pipes, as it is this way it is run on the track, you know, no heating and just full throttle when the lights go down.

It might get your thoughts on a different track.

[JanBros]

built a new dyno for my MX moped (50cc) using a complete drive-unit of a reach-truck

so I needed new data and tested also all my exhausts again (runs are with the CVT blocked halfway, so it's only the engine).
one off them (the best one, RL the blue in the excel) I made some time ago with an excel from Coker Racing Products, but sadly I've lost that file so I do not know the specifics of it any more. So I've measured it up as good as I could and compared it to the best I've gotten using FOS (GY the green one), and allthough the power is quite similar, their shapes are very different :

So my question : how come and what to change on them to get even better.

don't read too much in the HP-numbers, the dyno is "calibrated" using a good stock engine and adjusting the MOI so it put's out 2.5HP. after all it's all about comparing.

Data on the engine :
39x41.4
exh 188°
transfer 120°
sq 50% CR 12.8


it is for Moped-MX, has CVT but I can not change the final gearring/ looking for power at higher rev's is useless, as there is usualy/sometimes only 1 long straight, but there are a whole lot of slow corners and we would lose a lot more comming out of slow corners than we would gain on the straight.

[wobbly]

SwePatrick - I wasnt being negative at all. Just trying to point out valuable lessons learnt the hard way.

But I fully stand by my comments about being able to suddenly wind in 3* of advance and a) be surprised it made more power and b) it didnt blow up.
To wind in that much advance it HAD to be retarded severely initially or the com is too low to begin with.
You didnt answer the question about what the static com actually is, and what is the peak power advance number now is just as important.

Methanol works best when at least 20% rich over stochiometric , and when its that rich you dont loose power nor get any power fade from it getting hot.
But what it does do is allow way more compression - safely with what would be regarded as a "normal " advance curve.
We have a member on here who wins 125 hydro races at 20:1 - alot higher than even the 18:1 that was used on 130 ELF in GP racing.
EDIT - this makes way more power than less compression and alot more advance.

So how do you know you have the best combination of advance/com/egt if you dont have the egt data.
The pipe must have been designed with a bulk gas temp in mind - so how do you know you are even close to that - apart from the fact it revs to some particular number.
But Methanol always revs harder than theory would predict - as it operates as though you were using a PWM powerjet solenoid because its not affected by the carb going rich over the pipe peak.

Imho you simply cant tune accurately and make informed decisions without sufficient data.
Ages ago I detailed what happened after Jan told me about having a target egt that you stick to that eliminates that effect from any change being made.
I tested a huge range of reeds and insert stuffers and one stood out as being the best by quite a margin.
But after going back and doing the test all over again , and changing jets each time to hit the same egt number , what was the worst reed/stuffer setup was now the best
as it needed alot less fuel to make alot more power ie a better bsfc ( Kg fuel/Hp/Hr ).
I hadnt even noticed that each time i made a change the egt was all over the place , and the good reed was down on power simply because the egt was 35*C lower.

Several others have made the comment about CVT being a nightmare to dyno accurately with , due to belt slip changing with heat, and some have resorted to locking out the CVT pulley.
And they were logging engine Vs drive rpm to generate a slip readout to tune the CVT.
But the fat tyre eliminates tyre slip on the roller so thats a positive effect.

[husaberg]

built a new dyno for my MX moped (50cc) using a complete drive-unit of a reach-truck

[husaberg]

Kevin Cameron article about 2t scavenging and the Jante flow machine:

https://www.cycleworld.com/searching...nging-schemes/

Edit: another one

https://www.cycleworld.com/colliding...flow-symmetry/

In that cameron article with what it said about Kawasaki i can't help be reminded of how Jack Williams of AMC development fame used a homemade flow bench and added ink out of a airbrush to test for the areas with low flow that was mention in another cameron article.

They had to make their own flow bench as if AMC never made it they were not allowed to buy one, Typical pommy upper management.

Google found this

He was spraying ink into the airstream of the air/fuel mix going into the combustion chamber, and dynoing the results on an actual engine (using fuel/air, not air/ink !)
He found that if he could swirl the mix into the combustion chamber such that he didn't get any ink on the walls in the process, the bhp went up and up.

this came up when looking for it its from a camera built into a piston

[Larry Wiechman]

https://www.osti.gov/etdeweb/servlets/purl/317135

[SwePatrick]

SwePatrick - I wasnt being negative at all. Just trying to point out valuable lessons learnt the hard way.

But I fully stand by my comments about being able to suddenly wind in 3* of advance and a) be surprised it made more power and b) it didnt blow up.
To wind in that much advance it HAD to be retarded severely initially or the com is too low to begin with.
You didnt answer the question about what the static com actually is, and what is the peak power advance number now is just as important.

Methanol works best when at least 20% rich over stochiometric , and when its that rich you dont loose power nor get any power fade from it getting hot.
But what it does do is allow way more compression - safely with what would be regarded as a "normal " advance curve.
We have a member on here who wins 125 hydro races at 20:1 - alot higher than even the 18:1 that was used on 130 ELF in GP racing.
EDIT - this makes way more power than less compression and alot more advance.

So how do you know you have the best combination of advance/com/egt if you dont have the egt data.
The pipe must have been designed with a bulk gas temp in mind - so how do you know you are even close to that - apart from the fact it revs to some particular number.
But Methanol always revs harder than theory would predict - as it operates as though you were using a PWM powerjet solenoid because its not affected by the carb going rich over the pipe peak.

Imho you simply cant tune accurately and make informed decisions without sufficient data.
Ages ago I detailed what happened after Jan told me about having a target egt that you stick to that eliminates that effect from any change being made.
I tested a huge range of reeds and insert stuffers and one stood out as being the best by quite a margin.
But after going back and doing the test all over again , and changing jets each time to hit the same egt number , what was the worst reed/stuffer setup was now the best
as it needed alot less fuel to make alot more power ie a better bsfc ( Kg fuel/Hp/Hr ).
I hadnt even noticed that each time i made a change the egt was all over the place , and the good reed was down on power simply because the egt was 35*C lower.

Several others have made the comment about CVT being a nightmare to dyno accurately with , due to belt slip changing with heat, and some have resorted to locking out the CVT pulley.
And they were logging engine Vs drive rpm to generate a slip readout to tune the CVT.
But the fat tyre eliminates tyre slip on the roller so thats a positive effect.

I can´t remember i wrote somewhere or said in the clip that i was certain of anything....
And i recall that i didn´t want to push it on the dyno, i said something like 'we take it on the track'.
That should tell you that i know there is more lurking inside.
And still, i never said the 'engine' alone was hot, i said IT is hot!
That includes the whole bike.

And as i need to see if it have any response at all from almost dead cold i run it at about 25-30degree watertemp only when starting the pull.

Dragracing is a whole other way of tuning things, as it is the first ~100ft it needs to pull hard without hesitation when 'cold'
I run it somewhat low in compression yes(16-1), this to 'spill out' some energy through the exhaust, this to get some exhausttemp early in the run.
I am well aware that it would produce more power with say 18-1 och even 20-1 but this makes it harder to build heat and by that get the 'correct' engine powerband.
I use the fact that a 'cold' pipe pulls harder down low in the launch, making it easier to setup the cvt(it is tricky setting it up at high rpms).

We only run 201m(1/8), the run is over in ~6-6.5 seconds.
Tell me your builds produce good 60ft on the 1/8 with 25-30degree of watertemp and i will listen.
Dynonumbers are just numbers, but it should work on the track also.

And the dyno reports ~92hp to the crank, i would say that is darn good even thou it is not perfect tuned yet.
I´m guessing if putting in some more advance it will level out at somewhere in the area of 95-96hp to the crank.
95.5/198cc=0,48hp per cc

Aprilia RSA (roughly 59hp to the crank) on 124.7cc is 0,47hp per cc

Somewhere something is working quite good with these things that haven´t been professionally developed for years and years in an enginelab.
I do not need to know exactly all things with sensors and decimals, i read the plugs, as all dragracers do.

Tuning in dyno with cvt isn´t hard, you just set dyno up a little bit different(locks the gearratio), and setting up the cvt different from actual setup on the track.
Just put in some weight to get the cvt the change the gearratio early in powerband, by this you get the 'peak', setting cvt up for high rpm you might go past the peak and not getting the numbers at a lower rpm.

I run early in the pulls only ~250degree exhausttemp, it raises during the pull to about 400degree, pulls are taking ~4.5s.
Somewhere in the area of 430+-20degree seems to be the sweetspot
'cold' this engine peaks at ~13300rpm, and with some serious heat it peaks at ~13800-13900rpm.
But the torque cold down at 10500rpm is HUGE compared to 'hot'
Can´t remember the number on top of my head now thou.

[jonny quest]

You set up retarded ignition for when clutch is pulled in revving waiting for light.

This gets pipe hot for your run

[Frits Overmars]

I run it somewhat low in compression yes(16-1), this to 'spill out' some energy through the exhaust, this to get some exhausttemp early in the run.

Makes sense.

I am well aware that it would produce more power with say 18-1 och even 20-1

Not necessarily. It depends on how efficiently the pipe deals with the exhaust gas energy.

Tell me your builds produce good 60ft on the 1/8 with 25-30degree of watertemp and i will listen.

I do not expect Wobbly to loose much sleep over whether you are listening. We offer what we have to offer and what you do with it is your choice.

95.5/198cc=0,48hp per cc. Aprilia RSA (roughly 59hp to the crank) on 124.7cc is 0,47hp per cc. Somewhere something is working quite good.

The fuel maybe?

[wobbly]

Not interested in a flame war but I believe you are overlooking a couple of factors in the drag engine performance envelope.
Running Methanol it is technically normal to gain around 9% Hp simply due to the combustion energy increase of over 1/2 the A/F ratio.
With all out mods it is easily possible to double that increase - been there/done that.
So putting your 100cc cylinder back on petrol like the RSA that reduces the power to something like 0.39Hp/cc from the mechanical part development.

And why is it that in every form of drag racing the consensus is to be reving the engine right up to its mechanical limit ie 500cu in V8's going to 11000 + rpm
to take advantage of the gearing torque multiplication.
You are running the 100cc to 13000 , same as the 125 RSA peak Hp - seems to me you are leaving a shit ton on the table as using that 39Hp/100cc this would simply ratio up by 39*16000/13000 = 48Hp
if you maintain the torque at that rpm.
Plus add the fuels induced efficiency = 48*1.18 = 57Hp*2 = 114 crank Hp - and 16000 rpm is 25M/s piston speed on a 4.7cm stroke , very easily achievable and reliable even in kart scenarios - now you are getting
serious @ 0.57Hp/cc.
Then add in the gearing multiplication for way faster acceleration and or terminal speed, seems a no brainer - even if you halved the rpm increase to only 14500.

Edited to show the piston speed @ 4.7cm stroke - safe as hell.

[F5 Dave]

Those 100cc Roost barrels do look fantastic though. Far better than the 1978 rubbish we thought trying to triple port case reed was pushing the envelope. Pah . They would have been good to use, if maybe a planet away from the 'Spirit' of bucket racing.
But that was just rambling of a codger who didn't wish to push the written rule book.

[lodgernz]

Those 100cc Roost barrels do look fantastic though. Far better than the 1978 rubbish we thought trying to triple port case reed was pushing the envelope. Pah . They would have been good to use, if maybe a planet away from the 'Spirit' of bucket racing.
But that was just rambling of a codger who didn't wish to push the written rule book.

Says the codger whose 50 is still the fastest F5 bike in NZ.

[aljaxon]

in a nutshell
will a longer belly/shorter rear cone combo deter over rev more than a shorter belly longer cone?
same tuned lengths. same percentages.

ive realised i dont want to totally kill over rev in my ideal pipe for the puch road bike project.

[wobbly]

In a nutshell , a steeper rear cone has increased amplitude over a shorter duration = less front side and overev , more peak.
In fact a longer rear and shorter mid may be the go to in this case.

[Frits Overmars]

a steeper rear cone has increased amplitude over a shorter duration = less front side and overev , more peak.

Yup, up to a point. If the rear cone is too steep, the return pulse can turn into a shockwave before it reaches the cylinder and then you will have less of everything.
Al, you next question will probably be 'how steep is too steep?'
I've tried to incorporate the optimum rear cone ratio in my FOS exhaust concept. You can go shallower if need be, but going steeper won't do much good.