ESE's works engine tuner

[Peter1962]

Fu$%king rubbish carburetors, who needs them.

What we need is a MK2 kit, for the ktm-husqvarna-gasgas 250 and 300 TPI's. That is where the two stroke market is. They sell more than 50.000 of those TPI's per year. In fact, the KTM group is selling more 2 strokes then 4 strokes, not counting the 50cc mopeds.

In the hard-Enduro world championship, more than 50 % of the field are ktm-husky or gas-gas two strokes.

There are now a couple of firms who do a 'refllash' of the existing TPI chip, but that is not real evolution...

[ken seeber]

Below is a consolidated update on the DCI project. Taken a while, but lots of other stuff going on.

Like all good things, there is a happy ending.

Was pointed out that you need to pause on the various text cards to fully read them.


https://youtu.be/ae8qOvGoWgM

[jonny quest]

That is really cool Ken!

I'll re watch video when I have more time... but

Ultimate goal is heating air to expand.

Why do you think it seemed to rev quicker and higher with such a small carb via DCI? How is it getting enough VE through such a small hole compared to standard carb arrangement?

Are we wasting that much airflow through tunnels? Are we creating too much VE under piston to cause pumping losses?

[Flettner]

Below is a consolidated update on the DCI project. Taken a while, but lots of other stuff going on.

Like all good things, there is a happy ending.

Was pointed out that you need to pause on the various text cards to fully read them.


https://youtu.be/ae8qOvGoWgM

There is so much to still to be learnt, 'Ken the doer'. This is real intetesting. Keen to see the next step.
Might be interesting with a form of TPI.

[Flettner]

https://youtu.be/av-pdf2Gt5g

[Muhr]

.
Attachment 349566Attachment 349567Attachment 349568

Actual crankcase MAP sensor readings at idle 1.8k rpm, and 4k rpm and 10k rpm.

MAP sensor, Blue line. 500mV a division. 0-5V = 0-2.5 bar MAP sensor. The MAP sensor has a 1ms settling time which is common for these types of sensor.

Interestingly, at idle the crankcase pressure rapidly drops at TPO transfer port opening but at higher rpm and load this is not happening.

interesting reading

https://www.diva-portal.org/smash/ge...FULLTEXT01.pdf

[Frits Overmars]

interesting reading
https://www.diva-portal.org/smash/ge...FULLTEXT01.pdf

It certainly is. Thanks Muhr

[philou]

I cannot find the messages concerning the injection on the aprilia 250.

according to a certain Francesco who would have worked on it. It worked very well with 2 podiums.

with only one injector per cylinder, that seems weak.

[Frits Overmars]

I cannot find the messages concerning the injection on the aprilia 250.
according to a certain Francesco who would have worked on it. It worked very well with 2 podiums.
with only one injector per cylinder, that seems weak.

To the best of my knowledge no fuel-injected Aprilia 250 ever achieved a podium finishing, or any finishing for that matter. And unless I'm very mistaken, the picture in the left shows an Aprilia-500, not a 250. The RSW500 had four injectors: two in the throttle bodies and two in the crankcases. So I suppose your Francesco may have some explaining to do...

[philou]

I was wrong, he talks about the rsw 2 which is indeed the 500.

he maintains that there is only one injector. I do not believe it. one cannot be enough to feed properly

[TZ350]

.


I would much prefer to work with fuel injection but for now my 50 has a 30mm carburetor. A bored out 24mm OKO.



I hesitate to call my modification a pulsed power jet. But here is my attempt at a fuel enrichment device that can be PWM. The Ignitec ignition allows for mapping the pulse width against rpm. So if it works I can enrichen the fuel curve at peak torque and lean it off for over rev.



I am using a small air solenoid. Here is hoping that the fuel does not melt the seal and plastic parts.

[jamathi]

To the best of my knowledge no fuel-injected Aprilia 250 ever achieved a podium finishing, or any finishing for that matter. And unless I'm very mistaken, the picture in the left shows an Aprilia-500, not a 250. The RSW500 had four injectors: two in the throttle bodies and two in the crankcases. So I suppose your Fransesco may have some explaining to do...

It was unrideable, so they went back to carburetors...
No 250 Aprilia was ever raced with injection!
Injection was tried on the dyno, on the 125 engine, with no positive results...

[JanBros]

.
for now my 50 has a 30mm carburetor. A bored out 24mm OKO.

so is there any venturi left at WOT ?

[Condyn]

Looking for some guidance in understanding the fundamentals of two stroke ignitions and their relationship to compression. I know its a vague request, however even after much reading I am still questioning whether an engine with say 11:1 compression would be happy with the same advance as its 15:1 counterpart.

[Frits Overmars]

Looking for some guidance in understanding the fundamentals of two stroke ignitions and their relationship to compression. I know its a vague request, however even after much reading I am still questioning whether an engine with say 11:1 compression would be happy with the same advance as its 15:1 counterpart.

The seemingly simplest questions often require the most in-depth answers, Condyn. In today's two-strokes much depends on the exhaust pipe. A higher compression ratio before TDC means a higher expansion ratio after TDC; a greater part of the energy in the combustion gases is used in pushing the piston down. In itself this is fine, but it also means that less energy is left in those gases when they enter the exhaust pipe. And if that pipe is not fed with energy, it won't do anything useful in charging the cylinder for the next combustion cycle.
So a high compression ratio may give a stronger push on the piston, but the next cycles will suffer and the nett result depends on how efficient the pipe deals with the available energy.
Personally I am in favour of a low compression ratio for a competition two-stroke. A good pipe can triple the power of such an engine, as Jan Thiel has proven, so let's give that pipe something to work with.

Where does the ignition timing come in? The later you ignite, the later the combustion phase will be complete and the less expansion will take place between the end of combustion and exhaust port opening. So retarding the ignition is another way of transfering energy to the pipe.
An 11:1 compression ratio with early ignition may well behave just like a 15:1 compression ratio with late ignition, but once again it depends on the efficiency of the pipe.

If we were talking four-stroke, all would be clear. A poppet exhaust valve opens with an initial velocity of zero, so the initial exhaust pulse coming from a four-stroke is quite weak in comparison to a two-stroke pulse, where the exhaust port opens with an initial velocity of about 1,5 times the mean piston velocity, releasing a mighty big bang.
A four-stroke does not depend nearly as strong on pipe effects as a two-stroke does, so it needs all the compression ratio that can be built into it. But it will never be a match for an equal-capacity two-stroke.