Hi I have just modified my Impreza 2008 Hatchback 2.5 Turbo with Induction kit and exhuast system including decat ready for remap.

Car still has standard recirc dumpvalve/BOV and since I have fitted the induction kit I am getting quite an annoying open air dump valve sound coming back through the induction kit when I let the gas off boost.

I was hoping to get a nice wastegate flutter but instead have this annoying hiss.

Is this due to the standard recirc valve throwing the unwanted boost back out of the air filter

How would I go about getting rid of this hiss without any detremental performance or issues?

Many thanks

 

Fitting an induction kit will amplify noises that would have been there before but were hidden by the standard airbox, to get the flutter you need to blank the DV off

 

Will doing the blanking the DV have any detrimental performance/running isses or anything I need to be mindful of?

 

No not really, general rule of thumb is that the TD turbo’s are a bit stronger compared to VF but I think problems are rare.

 

Possibly be looking for a new turbo. Generally the vf series turbos don't like to much compressor surge.

 

I guess removing the recirc bov will cause more compressor surge?

 

 

In all honesty stick with the recirc, it’s the best option until you’re 400/450 +

 

Running your car on gas might not help

 

I would be running off boost until I have had the remap if I were you, induction and decat is quite a lot variables changed.