divil

I did some tests on this and I wanted to check that I tested it the right way. First, I checked that the small port on the top holds vacuum....that part was fine. Next, I wanted to see if air would leak form the side port (intercooler outlet) to the bottom (j-boot). I've read in a few places that if you remove it and try blowing though, it should be sealed in every direction. What I found was that with nothing connected to the little top port, some air does indeed leak through from the side to the bottom (not with me blowing, but with a few psi from a compressor). But, with the same pressure applied to the top *and* the side, it seals up fully and nothing comes out the bottom.

I'm not sure if this means it ok or not. I had assumed that there should always be the same pressure in both lines, but then I thought that since one is before the throttle body and one after, does that mean there is a delay before the full pressure arrives at the top of the BOV? That would mean air would be leaking back into the J-boot for a short time while boost is building.

Willard Bridgham 3

If you can blow in it anywhere, it's bad.

divil

I definitely can't blow through it, but I can make it leak with a little pressure from a compressor.

TurboTommy

If you don't have the little vacuum port connected, then a few psi of pressure (whatever it takes to overcome the spring inside) will indeed open the the valve. It's supposed to do that. (The little vacuum/pressure port is not connected so it won't equalize the pressure on both sides.)