I have an evo 8 with barely anything done to it, it is tuned but it has the metal evo 9 BOV and it is really loud. I'm pretty sure I don't have any boost leaks all I did was take the plastic one off and put the 9 one on. It almost sounds like the batmobile in the new batman movies when its going sideways and the tires make that noise on the cement, if that helps lol.

I feel like somethings not right. my buddy has a 9 with a tial bov and that thing just sounds quiet compared to mine.

EDIT: I also just switched from a electronic boost controller that was failing to a MBC. and it seemed to happen around this time.

 

installed backwards?