Wmscooby

iTrader: (24)

what the differnce between recirculating and atmospheric?

any help??

mark

nunosm

On lift off....the pressure produced either goes to the atmosfere (lost) or recirculates again to the induction system (after MAF).

Atmosferic dumps cause some fuel enrichment because the fuel was calculated based on the amount of air entered in the engine, and because that air is evacuated prior to the explosion, fuel isnt adjusted (could be good, to prevent lift-knock, could be bad if bore wash is produced, unburnet fuel explosion on uppipe, etc).

Either way, people exchange their dumps only if their engine is producing more boost (1.2B+) or just for the sound of the dump.

Bully3176

iTrader: (1)

Yeah
VTA Well, whenever the engine vacuum reaches the level the piston / diaphragm / spring is set for, the dump valve dumps the excess/pressurised air ( which the MAF has already measured and the ECU is now calculating the fuel for, etc. ) - this is brought about by the driver lifting off the accelorator ie the WWHHhhOOoooSSsshhhh you hear.

Rather than the recirc standard one passing it back into the exhaust and MAF sensor etc? Really its all down to a personal choice? Noise or not noise? Lots of argumets and threads posted on here about dump valves mate? Do a search on the threads and read away???