At what RPM should you get some noise out of BoV?

[Nurokil]

Maybe this is a really dumb question but..... I notice that compared to my Brother in laws s14 SR and my Best friends s13 red top i have to get to much higher RPM to get some noise. IE. I will have to get to around 1k lower then re4dline to get noise and i get like wah wah wah noise where my buddy gets a phisssss. tell me what ya think all. Is that the right amount of RPM to get a escape of spool or should i be releaseing some tension on the spring.

[krazydriver]

yeah you definitely need to loosen it.. quite a bit it sounds like. The sound your getting is compressor surge.

Set properly the BOV will vent even when your not "in" boost, because any pressure greater then whats in the intake manifold will cause it to vent. ie. revving it, the turbo will start to push air. It's no over atmospheric yet, but if you drop the throttle the pressure will remain high enough it should vent the excess.

loosen it until it stops surging, then slowly start tightening it back up. Depending on the BOV. You may need to remove one of the internal springs on it. I've got a Greddy RS and had to take out the bigger spring, leaving only the smaller one with the adjustment set about half way to get rid of surge. I can get it to vent @ 1500 rpm if i stomp on it for a second then let off.