Adaptability of the KA24de ECU

[jdzumwalt]

Is anybody familar how the ecu adjust for timing fuel delivery. On my WRX the ecu will advance timing to the threshold point of knock. If pipng accors it will pull timing till the car runs perfect.

It seems to me that my ecu has been advancing the timing since I installed my turbo kit. Does it learn the timing curve or is preset?


Gregg

[orion::S14]

It's something like:

Throttle position + airflow = a "load" value, from a map.

Then the "load" value is plotted vs RPM to determine ignition timing advance/retard.

That may not be exact, and the terminology may be off, but it illustrates the basic setup.

- Brian

[orion::S14]

Oh yeah...and if a Nissan ECU senses knock under ~4000rpm (I forget the exact RPM #), it will retard timing.

Above that, and the KS is ignored.

Our ECU's are not like a DSM ECU, with active knock control.

For the KA24DE in a 240SX, the ECU assumes a base of 20, and makes changes based on that. That's why it's so important to PROPERLY set the base timing, with the TPS unplugged. It's also why you can "trick" the ECU by setting the base low, and having the whole curve backed off by 2*, or whatever.

Hope that helps - Brian

[jdzumwalt]

so does the ecu have the ability to advance timing from the base map. Meaning that the longer you drive around it will learn a new timing curve and peak timing in certain locations within the map.

The reason I asking this is. If you increase timing you potetialy could start to create more boost off of the same duty cycle(with a boost controller) IE: My car was boosting .4 bar right when I started up took it around the block,. For two days I couldn't get it over .4 bar with the stock wastgate. Now it's starting to boost up to .6 and then coming back down.

My guess is that the stock computer has advanced the timing causing issues with the waste gate not being able to flow enough?

Any thoughts?

Gregg

[Maeda]

Ditch the O2 sensors, have it run in closed and fuck with it all you want on the dyno. Cheers.

[DuffMan]

Originally Posted by Maeda

Ditch the O2 sensors, have it run in closed and fuck with it all you want on the dyno. Cheers.

Worst
Advice
Ever!

[sr240mike]

Yes the ecu has learning capability. Im not sure how good the stock timing/fuel maps would be with a turbo. You are putting more load on the engine with a turbo so the ecu is probably advancing timing. You should try retarding the base timing a few degrees and see how it runs. Have you considered some type of engine management?

[Maeda]

Originally Posted by DuffMan

Worst
Advice
Ever!

Sarcasm my friend.

Ironically this is also what i'm running(long story).