turbo noise??

[aisekulic]

hi all just question, i have a 2003 mk4 gti, just recently got it flashed with GIAC, and installed an APR R1 DV. everything else in the engine is stock. when i accelerating and then back off the throttle i hear a flutter and whooshing sound? it kinda sounds like either a blow off of pressure, or maybe the turbo turbine is making the sounds. either way im not sure if its supposed to be there as i havent owened a turbo vehicle before, i love this car, and want to make sure everything is as its supposed to be. any feed back would be appreciated.

[sleg]

sounds about right, do you have a cone filter on? It makes the sounds from the turbo louder

[aisekulic]

the air intake is standard, i can hear the sucking noise on the right from the SIMIC, but the other sound is from the left where the turbo is i think ( correct me if im wrong) ive only noticed it since doing the GIAC upgrade

[AusScare]

ive only noticed it since doing the GIAC upgrade

Because the boost was raised quite a bit.

Sounds awesome hey

[aisekulic]

it does sound awesome... and it goes like a cut snake!!! so if thats what its meant to do... than that **** is bananas

[Merlin8r]

Yeah it's the diverter valve. When you come off the throttle the turbo has generated a nice slug of compressed air that you don't need anymore, so it has to get rid of it. Cars without a MAF sensor use a blow-off valve, which is that irritating vvvvvvv-PSSSSSSH you hear from ricers. But a MAF equipped car has already accounted for the air in the intake, so the valve just diverts it back to the start of the intake cycle.

On my stock GTI I can hear it between gear changes, and I like the subtlety. If you put a pod filter or CAI on I believe it gets a lot louder.