ESE's works engine tuner

[lodgernz]

I need to make something to let me map the curve in the stock box on my 2015 KTM 250SX engine, since I've been unable to find that information anywhere and I suspect it may not be suitable for pavement use.

I've hopes of figuring out how to use an Arduino and sensors to capture both the RPM and the spark event, but since my small amount of programming is 30 years in the past I've got a lot to learn.

It sounds like it might also be possible to use a signal generator to trigger the box and not have to build a mechanical test bed, but electronics are magic to me since I can't see the electrons moving. I bought a digital USB o-scope but I need to get one of my EE friends to walk me through how to use it.

Try this: https://kokoraskostas.blogspot.co.nz...ug-sensor.html

[Brett S]

I need to make something to let me map the curve in the stock box on my 2015 KTM 250SX engine, since I've been unable to find that information anywhere and I suspect it may not be suitable for pavement use.

I've hopes of figuring out how to use an Arduino and sensors to capture both the RPM and the spark event, but since my small amount of programming is 30 years in the past I've got a lot to learn.

It sounds like it might also be possible to use a signal generator to trigger the box and not have to build a mechanical test bed, but electronics are magic to me since I can't see the electrons moving. I bought a digital USB o-scope but I need to get one of my EE friends to walk me through how to use it.

Check out the BRC Racing Facebook page, Riley put up the 250 SX 2012 timing curve a few weeks back.

[Michael Moore]

Thanks Brett, the 250SX curve shown by BRC is a 2012 ignition that may be different from what my 2015 engine has but that is 1000% more information than I had before. It appears the stock ignition may not be bad at least as a starting point.

cheers,
Michael

[Jannem]

Having read here about the painstaking efforts of equalizing flow across the reed petals I came up with an idea that I decided to implement to the case I’m working on. A vertical reed channel splitter sandwhiched to the case halves between the reed and crankcase. Haven’t seen that done, but it should put the biggest pressure differentials right in the middle of the 2-petal reed openings and also direct the bulk of the flow around conrod after it has exited the reed block. I’ll post pics when I’m done, but wont test it separately as it’s pain to remove. Thought about attaching to the reed block exit and may test that in the current case, but not confident about the attachment being good enough to keep it from being digested by the engine in the long term.
Anyway, thoght I’d share fwiw.

[41juergen]

Many strobe lamps are designed for about 3000 rpm and at high revs they can suffer from an unknown amount of delay, or they overheat and perish, or both.
But you don't need a strobe lamp at all.
My setup (still in Italy, alas I have no pictures of it) looked a lot like yours but instead of a degree wheel I used a nylon spool of 114,6 mm diameter with a metal measuring tape glued around it. Figure out the necessary length of tape and you'll understand.
The spool with the measuring tape was stationary, the spark plug cable was connected to the tape, and the rotating shaft carried an indicator needle that ran
close to the tape. In order to avoid the spark current from pitting the bearing races, a carbon brush made up the connection between the rotating shaft and earth.

Frits, of course you are right. I use a strobe without any electronics and it looks like it works ok up to 12500 rpm. I had some detailed discussions with Borut from Zeeltronic how he had setup the tester he is using for his CDI development. And as I'm an mechanical engineer I went the less elecrtonical way....

And of course physics is the same in Germany and the Netherlands (or Italy ) the strobe heats up and I have damaged 2 lamps trying to run the whole curve from 2000 up to 12500 rpm in one shot...

[wax]

Me 2 Frits, at Lake Havasu running the Jetski Worlds i had a blanket over me looking at the timing with my trusty old neon.
Then I had to use one to see the old Win 98 laptop screen as well.
The team decided as I was ugly and a cripple to boot, the blanket should remain in place wherever we went cheeky bastards.

Im off to lake Havasu this year to race the world finials in vintage wobbly

[motogpdriver]

Frits, of course you are right. I use a strobe without any electronics and it looks like it works ok up to 12500 rpm. I had some detailed discussions with Borut from Zeeltronic how he had setup the tester he is using for his CDI development. And as I'm an mechanical engineer I went the less elecrtonical way....

And of course physics is the same in Germany and the Netherlands (or Italy ) the strobe heats up and I have damaged 2 lamps trying to run the whole curve from 2000 up to 12500 rpm in one shot...

found these:
https://www.youtube.com/watch?v=JkMFbGb6hEs

http://www.magnet-valreas.fr/style/m...ge-karting.jpg

http://www.magnet-valreas.fr/style/m...umage-kart.jpg

[Frits Overmars]

Me 2 Frits, at Lake Havasu running the Jetski Worlds i had a blanket over me looking at the timing with my trusty old neon. Then I had to use one to see the old Win 98 laptop screen as well. The team decided as I was ugly and a cripple to boot, the blanket should remain in place wherever we went cheeky bastards.

It's a cruel world Wob. I hope you insisted on a set of custom-made company blankets .

[Carel H]

I never thought of LEDs Carel. Surely they now must be cheaper than neon tubes, let alone amplified strobes. What can you tell us about their delay?

Being semiconductors, they're instantaneous on and off. A quick Google search mentions nanoseconds, not microseconds. And of course you are free to use as many leds as you wish and with short pulses: overvoltage.

[Frits Overmars]

Being semiconductors, they're instantaneous on and off. A quick Google search mentions nanoseconds, not microseconds. And of course you are free to use as many leds as you wish and with short pulses: overvoltage.

At 12000 rpm a 1 nanosecond delay equals a deviation of 0,000072 crankshaft degrees. I think I can live with that . Even a 1000 nanosecond delay would be fine.

[TZ350]

.
I have been trying to figure out a way of determining the relative air flow through my 2T motor.

From previous experience we know mass air flow meters don't work and that using the Ecotrons MAP sensor to measure the pressure in the crankcase or pipe just wound up with an average that slightly reduced below ambient as the motor came onto the pipe and flow through the motor increased.

I tried measuring the residual pressure pulse in the cylinder just before exhaust port opening. That worked well but did not tell me anything meaningful about air flow and fuelling requirements. Only whether the motor had fired or not. The best I could do with that information was to arbitrarily reduce fuel on the next cycle.



My new line of thinking is to use a pressure sensor and an Arduino to determine the difference between the maximum and '
\minimum crankcase pressure each cycle and feed this value as a MAP signal to the Ecotrons EFI CPU for processing. I am picking this difference in pressures will be a good indication of mass air flow and therefor fuelling required.

Dyno runs taken in reducing 10% throttle position steps.

If the pressure difference idea works then I might be able to use the Volumetric efficiency VE map with the Ecotrons EFI system for the troublesome area below the 20% TPS region and the Alpha-N map for power. From experience I know that Alphan-N works well above 20% TPS.

Determining an indication of the mass air flow by finding the difference between maximum crankcase pressure as the piston descends and the minimum pressure as the pipe sucks the air/fuel mixture from the crankcase. This pressure difference must say something about the mass air flow and therefor the fuelling required, and I am guessing the pressure differential will follow the torque curve.

Hopefully, anyway if this does not work, there is always booze ....

[F5 Dave]

We live in the country with possibly the best Sav in the world. And for a starter maybe the best craft beer.
Yup. There's plenty to be said for drowning your sorrows.
Geez must get to the Dyno.

[SwePatrick]

.
I have been trying to figure out a way of determining the relative air flow through my 2T motor.

I had a thought when reading your post, what type of airmass sensor did you use?
Heated film or hot wire?

Why not go 'backwards' and use the older ones cars used, with a 'flap' inside that turns a potensiometer:



These are almost mechanical and quite easy to build a smaller one if needed.
Thare are older japanese cars with quite small ones.
The one on picture is about 3" where you clamp the hose.

[F5 Dave]

We live in the country with possibly the best Sav in the world. And for a starter maybe the best craft beer.
Yup. There's plenty to be said for drowning your sorrows.
Geez must get to the Dyno.

Oh yeah
Panhead (Yeah I know) XPA. Fantastic.
followed by Spy Valley Sav.
With bbq smoked eye fillet steak and chicken bacon sausages
Life doesn't get much better.
Well. . Depending how the rest of the night goes. . .

[F5 Dave]

Oh. Where are my manners?

Saturday night musical interlude.

https://youtu.be/3lw6MZBmY-U