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Fooling the ECU (timing) - Is this possible???

gtstii

By gtstii,
in Engines & Forced Induction

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gtstii Collaborator

gtstii

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I was just wondering what input it is that the ECU uses to retard timing etc when we all make mod's.

Is it the factory boost sensor/gauge? Does it determine if boost is above the factory level, and then the ECU retards timing and overfuels to compensate?

If this is the case, for the people who already have SAFC's to control their A/F ratios, would the following work?

- bleed air off the line going to the factory boost sensor/gauge so that it see's less boost and therefore the ECU won't retard the timing etc....

- Then use the SAFC to tune fuel ratios and should find that the ECU isn't retarding timing b/c of too much boost.

Is this possible???

thanks

Cubes Grand Master

Cubes

Posted
Posted

It is all based on the AFM basically. The AFM measures the volume of air entering the engine and then refers to the maps in to the ecu then the ecu dumps fuel in to the cyclinders and possibly pulls a little timing if it thinks that the air entering the engine seems a little od.

Its all stored in the ECU's little brain. :)

From what i've seen on the R33's is that the SAFC is good up until around 220rwkw then it seems to run out of adjustment ?!? not sure but power dips start occuring which is not good for acceleration.

gtstii Collaborator

gtstii

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so is there no way to "fool" the ECU into not retarding the timing?

By having an SAFC and adjusting the A/F ratio that the ECU sees from the AFM, wouldn't this mean that the ECU would then not retard the timing because it "thinks" the Air/Fuel ratio is ok??

b2barker Enthusiast

b2barker

Posted
Posted

The knock sensor is the one that retards the timing. You are braver than me if you want to fool that one. Address the cause (ie. charge air temp, boost, compression). Trying to fool the boost limit is another one to avoid. It doesn't take out timing it cuts fuel.

The 220rwkw is the limit for a number of things, like AFM range, turbo and injector flow. It's not the SAFC that's the limitting factor

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