ok i know what you guys mean.
Well firstly when i am between 2,000 and 4,000 rev's and i let go of the gas i get a Flutter sound.
So that's how i am preety sure its a compressor surge..
as the sound come's out first from the POD Filter and then from the BOV....
Read on a few other forum's that it's a compressor surge which is :
Compressor surge is a condition caused, generally when a car with a turbo has a BOV that fails (or no BOV at all). When the driver slams the throttle plate shut, there is still compressed air in the charge pipe.
The turbo, however, has no power to spin, b/c theres no load on the motor ( ~0-5% TPS) so theres no exhaust.
This causes there to be more pressure on the turbocharger to backspin than spin in a forward direction.
Can any one relate to this from having a similar issue?