if you follow the pipe work from the fmic on the right hand side lookin in the engine bay, there should be a tube thats blanked off around where the top mount would have been, i beleive you need an adapter that fits into the blanked off pipe, a dump valve and bov are the same thing, you can have 2 kinds, recirculating, and vent to atmosphere which is the one that makes the pssst noise.i don't think one is better than the other apart from the noise which is a personal thing, like or dislike