ESE's works engine tuner

[marsheng]

Wallace you are making too many assumptions ( errors waiting to be revealed ) when saying the Ignitech rpm sensing is affected by in cycle
speed variation.
This is not the case - the ECU measures the time taken between the voltage pulses from the trigger, with an algorithm that averages the previous
3 cycles and this predicts the current acceleration rate, that then calculates the rpm for the cycle about to be given a spark.
This is the trickery that allows the system to fire a spark before or after the static set base timing.
Thus its the time taken per complete rev that is used in the calculation, instantaneous radial velocity is irrelevant.

Point taken.

[nine-thirtysix]

Could it be that the Ignitech algorithm says "the soft limiter must always start before the hard" means they can not both start at 15000 and the soft is before that?
I have no idea but it clearly limited power! And with a engine with max. power at 11000 to 11500rpm seems hard to reach tho.

[Haufen]

Know some oddity:

I set the rev limiter soft and hard at 15000 since I thought I will never hit that. But found out that it misfires at about 11500 to 12000! After that I changed for 16000rpm and it reved more...now it is at 20000rpm and hopefully will never distract again. I don't know what happend there in the ignitech...

I messured mapping points from an YZ125 and I know this bike pulls extremly hard bellow 6000rpm and revs quite good.
And the odd: max. advance 27°! And this worked far better for my CR then the stock max. 37°.
Thoughts why?

Check for other active functions which may activate the soft limiter or rev limiter, such as acceleration threshold (set to max value the sw allows), deactivate everything you find, then test again. Also check for cables which might connect accidentially in your loom (eg start limiter).

Maximum power is usually achieved if the max. pressure inside the combustion chamber is in the range of 15° CA after TDC. If yours is eg 5° after tdc with 37° advance, then you are wasting too much energy while the piston is still on it's way up. Normally the max. advance is knock limited, but if the compression is low enough for the engine not to knock (your exhaust PV does go down completely?), then this is a typical behaviour.

[wobbly]

There are many variables to be taken into account but under the pipe ( with no PV ) having 30 to 35* advance is perfectly normal
and I emphasis " for a race engine " which a MX bike certainly isnt.
If you ride around on part throttle for any length of time with this advance it will simply deto to death.
With the PV down the cylinder pressure will be much higher, so 25 to 30* is normally all that can be run to achieve best power.
If the com is optimized for the fuel,and the overall tuning is well executed, then ALL race engines end up with near on 15* advance at peak power.
Then depending upon several factors like pipe length, having a solenoid PJ etc. you can end up with 3* of timing in the overev to get heat into the pipe - to make it rev on.
This is a tricky exercise to control, as then alot of the combustion energy is released late in the cycle and this makes the egt continue to rise with rpm.
If not being closely monitored then its easy to get thermal runaway, with fuel burning in the header,and you end up having to jet way richer to simply cool the piston, ie not make power.
Thus in many cases a flat line after peak of around 10* stops the egt from continually rising in the overev, and makes jetting much easier for those not fully aware of whats going on.

[F5 Dave]

Saturday and not much going on (except the smell of a smoked paprika and chorizo infused lasagne) so time for one of my music interludes. Today's earworm.

http://m.youtube.com/watch?v=4jZBwyG7HPs

[nine-thirtysix]

Check for other active functions which may activate the soft limiter or rev limiter, such as acceleration threshold (set to max value the sw allows), deactivate everything you find, then test again. Also check for cables which might connect accidentially in your loom (eg start limiter).

Maximum power is usually achieved if the max. pressure inside the combustion chamber is in the range of 15° CA after TDC. If yours is eg 5° after tdc with 37° advance, then you are wasting too much energy while the piston is still on it's way up. Normally the max. advance is knock limited, but if the compression is low enough for the engine not to knock (your exhaust PV does go down completely?), then this is a typical behaviour.

Thanks for your answer,
soft limiter and rev limiter is at 20000rpm and acceleration threshold is at 20000rpm/s. It can be set higher but couldn't try it yet...but seems hard to reach by now. There nothing unnecessary activated. and the loom is fully checked.
But for now I think it's working ok (except the one strange setup) since it's seems to be rev limited by it's gas dynamic, may be just because the iginition timing is still not spot on for the best overev behavier.

With the stock ignition on the dyno max power was at 11000 and timing is at 14° for now couldn't try more yet. I want to install the know gauge before.
My PV timing is set at 164°....OEM is 155° but the higher setting improved the transition on the OEM ECU. I'm not done wih all back to back testing so next time I will try the 155° again.

[nine-thirtysix]

There are many variables to be taken into account but under the pipe ( with no PV ) having 30 to 35* advance is perfectly normal
and I emphasis " for a race engine " which a MX bike certainly isnt.
If you ride around on part throttle for any length of time with this advance it will simply deto to death.
With the PV down the cylinder pressure will be much higher, so 25 to 30* is normally all that can be run to achieve best power.
If the com is optimized for the fuel,and the overall tuning is well executed, then ALL race engines end up with near on 15* advance at peak power.
Then depending upon several factors like pipe length, having a solenoid PJ etc. you can end up with 3* of timing in the overev to get heat into the pipe - to make it rev on.
This is a tricky exercise to control, as then alot of the combustion energy is released late in the cycle and this makes the egt continue to rise with rpm.
If not being closely monitored then its easy to get thermal runaway, with fuel burning in the header,and you end up having to jet way richer to simply cool the piston, ie not make power.
Thus in many cases a flat line after peak of around 10* stops the egt from continually rising in the overev, and makes jetting much easier for those not fully aware of whats going on.

Thanks for all the informations,
for now I can just watch the piston and plug...
I'm currently working on an LCD-modul to show the value of a thermocouple where I have some laying around. But they have a responce time (change from -40 to 1100°C) of 33s so I'm not sure how much the temperature will change and how long it will take to see it on the screen.
How much is the life reduced if I peel them?
I scrumple a little bit to do that since you know they are not cheap!


If you can use a power valve what minimum timing do you use?

Thank you!

[wobbly]

The only thermo's worth using are the exposed tip type made by EGT Industries.
The response time is very very fast and they are the only probes with a 2 yr guarantee, only cost 62USD.

[SwePatrick]

You're mixing up two things. The rpm redline is not the rpm where an engine delivers its maximum power but the maximum rpm that an engine will sustain without flying apart. Hence my reference to the Ryger that refuses to fly apart even at 54,5 m/s.
Of course a conventional two-stroke can have its maximum power at greater piston speed than 23,6 m/s but that maximum power will probably be lower than that of the Aprilia RSA because, as you rightly say, the blowdown and scavenging time areas will become too small.

In this mythical engine Ryger..
Has someone ever questioned the flamefront´s speed?
When tuning foulstrokengines you can actually rev the engine faster than pressure can build, and there´s when the engine suddenly makes no power anymore, it just 'hits the wall'.
Common problem with Big V8 engines in dragracing.

[crbbt]

Ive got it!

the Ryger is a pulse detonation engine

[dark art]

In this mythical engine Ryger..
Has someone ever questioned the flamefront´s speed?
When tuning foulstrokengines you can actually rev the engine faster than pressure can build, and there´s when the engine suddenly makes no power anymore, it just 'hits the wall'.
Common problem with Big V8 engines in dragracing.

That doesn´t seem to be a problem in f1 cars (old WTCC cars comes to mind as well). Maybe because they run lower compression or fuel diferences?

[wobbly]

Maybe flame front speed comes into play past 20,000 rpm where the power is dropping due to
time/area constraints as well.
But as the Ryger makes it 70Hp at 17K, this is obviously not affecting efficiency at all.

[Frits Overmars]

In this mythical engine Ryger.. Has someone ever questioned the flamefront´s speed?

Maybe flame front speed comes into play past 20,000 rpm where the power is dropping due to
time/area constraints as well. But as the Ryger makes it 70Hp at 17K, this is obviously not affecting efficiency at all.

If there is a flame front, its speed will come into play long before 20.000 rpm. But in the Ryger there does not seem to be a flame front as we know it, which is very beneficial to efficiency, plus it will effortlessly rev past 30.000 rpm.

EDIT: I was going to attach a comparative video of Spark Ignition, Diesel and HCCI combustion modes, but I can't upload the 5230 KB GIF-file nor the 5103 KB ZIP-file. Suggestions, anybody?

[Dutch Fisher]

Frits all ICE have flame fronts, even gas turbines do.
The speed of the front is down to the intensely and size the of the turbulence regime.
As the species get smaller the front wrinkles are greater and the front area itself increases.
The greater the front area the faster the fuel/air volume is burnt.
As rpm rises the turb rises too staying ahead of any wall hitting.
A large % of why very high revving engines need less anti-knock octane


Want to know more.. then google Taylor Microscale, and Kolmogorov's theory

EDIT: I was going to attach a comparative video of Spark Ignition, Diesel and HCCI combustion modes, but I can't upload the 5230 KB GIF-file nor the 5103 KB ZIP-file. Suggestions, anybody?

Video Gif maybe uploadable to YT

[Flettner]

Ive got it!

the Ryger is a pulse detonation engine

Perhaps truer than you think. Maybe Harry has learned how to control HCCI, would answer a lot of questions.