I finally got around to installing my new TD05-16G. Everythings hooked up right (i think) and Im running 9-10 psi. When I let off the throttle it sounds like a rally car; the bypass valve makes a fluttering noise. Its the stock bpv, and I know a few people here have a similar setup. Any ideas of whats causing this and how to fix it?

Thanks,
Jim

i dont htink thats compressor surge, i believe that is simply a BOV flutter. its rather normal. I asusme your venting to ATM?

Also, there are many vehicles that run about 8psi w/o a diverter valve from the factory. So many of us suggest that it is semi-safe to run 8psi w/o a BOV at all.

Rember also that the WRX Diverter valve is desgined to recirculate. Are you getting a check engine light right now, and a rough idle? If so, its probably because the BOV is leaking at idle. If you can confirm this, than you need to "Crush" the bov.

-Jake

Well, the fluttering noise from the blow off valve is the audible part of compressor surge. You can read about it on the Go Fast Bits website, or the book Maximum Boost.

Im using the stock recirculating bypass valve of the legacy turbo, which is probably too small in the first place. Even at 8-10 psi, the TD05 can push alot more air than the stock VF11.

-Jim

sooo where did you find the td05 ...

When I installed my VF22 I thought the same thing. The turbo was SOOO much bigger and made such a diff sound, I thought I was getting compressor surge. I switched over to an HKS SSQ BOV at the same time and thought I was hearing what you think you are hearing.

If you have installed a larger IC as well (which I also did) there is a LOT more air under pressure- even if you are running the same general PSI. Your volume of air under pressure is greater, even though the pressure hasn't changed. The blow off takes longer and sounds different cuz there is simply more air. Think of it as 10 cubic feet of air at 15 PSI versus 1 cubic foot of air at 15 PSI. It's the same pressure, there is just more to blow off.

Dunno if that is your issue, but it sounds like it to me.