I have a ebay "greddy" Type RS BOV and I just had MS installed so with the IAT in, we took off the AFM and there was compressor surge. I adjusted the nut on the BOV and tried to loosen it as much as possible, no luck.
I then took out the BOV and took it apart and took off the inner spring and left the outer spring in. I then put it all back together. Now there's flutterdump. Went around the block multiple times adjusting the screw and ended up at it's softest point. Still flutterdump. Like this:
but the delay is not as long.
I notice it only happening at lower RPMs, while the BOV make a "pew" sound. At higher rpm and when boost is around 6psi and up it makes a loud WHOOOSH sound, all bov no surge/flutter (sounds almost identical to the video around 0:50 sec)
My question is do I need a bigger/stiffer spring or smaller/softer?
I have yet to try to "inner spring" which is smaller, but just thought I'd ask anyways.