shailet

Now, correct me if I am wrong in my logic here but I think having a BOV and full decat will minimise det. If a BOV vents excess air to atmos then the ECU is overfuelling, and if a full decat causes the mix to run lean (i think?) then they should compliment each other and bring the F/A mix to acceptable levels. Am I right or wrong about this?

ScrappyDoo2

wrong

alloy

If only it was that simple

ScrappyDoo2

As alloy said - it isn't simple to explain or prevent and there are many different causes. I understand your thinking (ish) but remember det tends to occur under load and when the engine is working hard in high boost,hot running due to high boost/lean mixture, and or high rpm scenarios. The slight and momentary enrichment you talk of with a BOV happens when you've come off the revs and change gear or are on/off feathering the throttle and therefore has absolutely no influence on whats going on between the gear changes when det is possible.

RedScoob

It doesn't quite work like that..... The BOV isn't there to prevent overfueling, but to prevent pressure build up and turbo stalling. If you mean running rich because of an air leak (which some BOVs apparently do) then you are loosing turbo eifficiency anyway.... I guess in that situation, you may get back the stoichiometric (ideal air/fuel mixture) balance by leaning the mixture as a by-product of decatting the exhaust, but the odds against it would make it pretty unlikely that it would be spot-on.
I think that's accurate, I'm sure someone will pipe up if it's wrong.....

shailet

cool, appreciate the info chaps. I guess really best thing is to remap once a full decat is installed to avoid any probs with fuel/air mix etc.

Redscoob, reg BOV and overfuelling - I meant that the excess air is being vented instead of recirculating back, so the ECU is basically putting in the amount of fuel it thinks it needs for the amount of air BUT it doesnt compensate for the air that has been vented by the BOV resulting in overfuelling.