ESE's works engine tuner

[SwePatrick]

Well,, you have the answer

This summer i dynoed a small 50cc to 19.22hp, and we never started from standstill.
We rolled up into about 200rpm on the roller, then gave it hell

After a run there wasn´t almost any heat buildup at all.
In the future, try remember that, start from rolling.

This is much more less aggressive to the belt and gives more precise numbers from pull to pull.

Rgds.

[RomeuPT]

good video from VHM

https://www.youtube.com/watch?v=4KRwOObWCtA

[Frits Overmars]

If you monitor the exhaust return pulse, you can see whether it arrives at the exhaust port too soon, too late or just in time, and then you can adjust the ignition timing accordingly.
No need for rpm-throttle-advance tables anymore; not even a need for exhaust gas temperature measurement anymore.

What Frits if you have new exh. and make other cdi curve's all not respons better then OEM part ( cdi )

With my system there would not be any CDI-curves anymore. Instead of looking up the prescribed amount of ignition advance for a certain rpm and thottle position,
the CDI would constantly monitor the exhaust pulses and adjust the ignition timing accordingly. It would also automatically adjust to a different exhaust pipe.

Always had thought that this dellorto used in the Aprilia would be better then keihin and read at pit lane that it wasn't exacly that way. Was any component from the Aprilia made in Japan or other place besides Europe?

Spark plugs, piston rings and big end cages, as Jan wrote. And, funniest of all, Keihin powerjet valves on the very special (incredibly expensive) Dellorto carbs .

What would had happen in your opinion if the 125 2t was still at GP, do you think it would have achieved 60cv by now after more 6 years of R&D?

6 years? As from 2008, Aprilia had to make do without Jan Thiel. That's 9 years. And I think it would have been realistic to expect an improvement of 1 hp per year.
And what do you think would happen if a 2007-version of the Aprilia RSA125 was fitted with 2017-tires and turned loose on the Moto3-class? They might as well hand over the victory bowl to its rider before the start.

[lohring]

What is the red material. Nylon seal?

Sent from my SM-G900F using Tapatalk

It's a silicon seal material that can be changed by unscrewing the end. That way it will fit several stinger sizes. An o-ring containing end plate might be an alternative.

Lohring Miller

[RSC]

I've been looking into the MVX250 electrical system and noticed it has TCI instead of CDI ignition,as well as a field coil alternator instead of a permanent magnet one.Both seem kind of an unusual option,do they have any inherent advantages?

[adegnes]

Well,, you have the answer

This summer i dynoed a small 50cc to 19.22hp, and we never started from standstill.
We rolled up into about 200rpm on the roller, then gave it hell

After a run there wasn´t almost any heat buildup at all.
In the future, try remember that, start from rolling.

This is much more less aggressive to the belt and gives more precise numbers from pull to pull.

Rgds.

Thanks for the advice!

[Nath88]

With my system there would not be any CDI-curves anymore. Instead of looking up the prescribed amount of ignition advance for a certain rpm and thottle position,
the CDI would constantly monitor the exhaust pulses and adjust the ignition timing accordingly. It would also automatically adjust to a different exhaust pipe.

This is interesting and not so difficult to implement. Could the pulse timing feedback work between a maximum and minimum timing curve? So it could adjust for changes in pipe wall temp, fuel mixture and pipe design?

I still have a few electrical parts to get for my sensor, but the housing is finished, will test later today. It could do ignition timing feedback for sure, just measure time between pressure peaks and compare against RPM, output a signal for the CDI that corresponds with exhaust wave too fast or too slow. Why hasn't anyone done this yet?

[Nath88]

Just tested the pulse sensor. I think this will work well. Would be able to measure time between pulses if you wanted to.

[ken seeber]

Nathan,
That's pretty cool, well done. Can I presume the positive pressure pulses are shown as -ve in the Y axis? They do seem to correspond with a fire. I suppose the closer to the pipe the better in terms of response delays etc. Do you think the piezo could stand being faced directly to the pipe wall or embedded in the exh port duct?

[Nath88]

Can I presume the positive pressure pulses are shown as -ve in the Y axis?

Yep pressure rise is shown as -ve. I'll rig up an external trigger so I can speed the scope up and look at the pressure waves over a cycle.

Do you think the piezo could stand being faced directly to the pipe wall or embedded in the exh port duct?

Probably not possible without some isolation like a duct or hose. It's basically a brass disc with some crystals stuck on the back, the crystals are the limiting factor, they lose their formation/polarity like a magnet at temperature. If it was in a heatsinked housing you could get it closer. The hose length on mine will be 150mm, so about half a millisecond delay. The volume in the sensor housing is minimised so the amount of mass moving back and forth in the hose and conduction of heat should be minimal also. If you filled the hose with something other than air the response would be faster but obviously damped as well, could be a possibility if the concept proves to be good.

[Frits Overmars]

With my system there would not be any CDI-curves anymore. Instead of looking up the prescribed amount of ignition advance for a certain rpm and thottle position,
the CDI would constantly monitor the exhaust pulses and adjust the ignition timing accordingly. It would also automatically adjust to a different exhaust pipe.

This is interesting and not so difficult to implement. Could the pulse timing feedback work between a maximum and minimum timing curve? So it could adjust for changes in pipe wall temp, fuel mixture and pipe design?

Working between upper and lower timing safety limits would be no problem. And changes in pipe wall temp, fuel mixture and pipe design would not even come into play.
All the system would do is check wether the exhaust return pulse arrives just before exhaust port closure. If the pulse arrives too late, retard the ignition which will raise the EGT and the speed of sound. If the pulse arrives too early, advance the ignition timing. And yes, it would be good to have a limit set for safe maximum advance.

I still have a few electrical parts to get for my sensor, but the housing is finished, will test later today. It could do ignition timing feedback for sure, just measure time between pressure peaks and compare against RPM, output a signal for the CDI that corresponds with exhaust wave too fast or too slow.
Why hasn't anyone done this yet?

My original idea was to use a crank angle decoder, but your idea of measuring the time between pressure peaks and comparing it against rpm is much simpler.

Why hasn't anyone done this yet? I could not do it on my own because my electronic skills are insufficient, and the works reaction was: "We are winning anyway. Why complicate things?" My claim that substituting EGT measuring with a more direct, effective approach was not a complication at all, could not persuade the bean counters.

[adegnes]

Working between upper and lower timing safety limits would be no problem. And changes in pipe wall temp, fuel mixture and pipe design would not even come into play.
All the system would do is check wether the exhaust return pulse arrives just before exhaust port closure. If it arrives too late, retard the ignition which will raise the EGT and the speed of sound . If the pulse arrives too early, advance the ignition timing. And yes, it would be good to have a limit set for safe maximum advance.

My original idea was to use a crank angle decoder, but your idea of measuring the time between pressure peaks and comparing it against rpm is much simpler.

Why hasn't anyone done this yet? I could not do it on my own because my electronic skills are insufficient, and the reaction at Aprilia was: "We are winning anyway. Why complicate things?" My claim that substituting EGT measuring with a more direct, effective approach was not a complication at all, could not persuade the bean counters.

Clever!
..........

[dutchpower]

Working between upper and lower timing safety limits would be no problem. And changes in pipe wall temp, fuel mixture and pipe design would not even come into play.
All the system would do is check wether the exhaust return pulse arrives just before exhaust port closure. If it arrives too late, retard the ignition which will raise the EGT and the speed of sound . If the pulse arrives too early, advance the ignition timing. And yes, it would be good to have a limit set for safe maximum advance.



But then you most have a hell of a good engine Frits

[Frits Overmars]

But then you most have a hell of a good engine Frits

That's what I'm aiming for anyway Dutch. But the scheme should work on any two-stroke engine.

Just tested the pulse sensor. I think this will work well. Would be able to measure time between pulses if you wanted to.

Nathan, the time between the primary pulses, generated at exhaust port opening, will equal one crankshaft revolution. But what we need for ignition timing control, is the time between a primary pulse and its return pulse.
If I take the Aprilia RSA engine as an example, the primary pulse is generated by an exhaust port releasing a cylinder pressure of up to 12 bar. The return pulse generates a cylinder pressure of about 2 bar. Do you think it is feasible to distinguish the return pulses between those violent primary pulses?
Maybe like this: a pulse that is registered more than half a revolution-time after the ignition spark (and before the next spark), occurs after BDC, so it must be a return pulse.

[shnaggs]

Working between upper and lower timing safety limits would be no problem. And changes in pipe wall temp, fuel mixture and pipe design would not even come into play.
All the system would do is check wether the exhaust return pulse arrives just before exhaust port closure. If the pulse arrives too late, retard the ignition which will raise the EGT and the speed of sound. If the pulse arrives too early, advance the ignition timing. And yes, it would be good to have a limit set for safe maximum advance.

My original idea was to use a crank angle decoder, but your idea of measuring the time between pressure peaks and comparing it against rpm is much simpler.

Why hasn't anyone done this yet? I could not do it on my own because my electronic skills are insufficient, and the works reaction was: "We are winning anyway. Why complicate things?" My claim that substituting EGT measuring with a more direct, effective approach was not a complication at all, could not persuade the bean counters.

Frits, If 2 strokes were in F1 I think they would have done this. That statement "We are winning anyway......" is a passive answer, which is not how to better the 2 stroke. But I guess If I was a team manager with the big money people looking down on me, I might do the same....Why screw with something that is currently working???

Frits, If I win the Lotto, we (ie, you, Wob, Jan, and I'll just be there for fun) are going to build the most badass 2 stroke ever!!!!!