I have the greddy turbo kit with a Type S bov on my 97 civic Ex. When I build up to zero vacuum and then into boost and let off the gas, the turbo or bov is making a flutter sound while blowing off(similar to the drag turbo shutter). I cant decide if its bov flutter or compressor surge. I've loosened up my bov quite a bit, but it still does it. The car is running good and I dont feel anything funny in the peddle though. Is this normal and ok, or is there a problem that needs to be looked at? thanks

 

my friend had the same problem with his the exact same BOV on his DSm. What I would do is check the vacuum lines for any leaks or holes and just replace them. One other thing is that you might have a bad spring in the BOV. How much boost are you pushing anyways?