BPV orientation.. What do you guys think?

**Saturnine** · 07-29-2004 09:07 PM

Soo.. I posted this thread earlier today..

My post from earlier in the day

Im still not sure what's the best way after reading the posts on my thread, and the posts on this additional thread:

Awahl63's forge bpv post

I have always thought that the BPV should be installed in the mannor that explained in my post in the B6 forum..

JMG and Hass both pointed out that Forge bpv's work in the OEM position, but all the other valves (with some exceptions of course) seemed to be installed in "reverse". I dont understand how the forge valves (and others that are positioned in the OEM fashion) can work efficently and effectivly..

In this pic you can see how the internal piston on the bpv moves.. The red arrow is the movement of the pistion, and the purple arrow is the route of the air that gets diverted back into the intake. Pressure from the IC hose pushes the piston up and the air gets rerouted back into the intake track..

How can a bpv work if its placed in the OEM position??

Disscuss please

**DDQ** · 07-29-2004 09:36 PM

Well, the concensus is that all BPVs will work in both positions, no matter what. But, for the "best" performance (read: millisecond response time that you'll never never ever notice), then you want to orient the BPV facing the direction that holds the most pressure.

This site is the only one I found that did actual testing of the BPVs with pressure tests: http://dv.mistertam.com

I think the biggest reason people are concerned about which direction to install is that the rubber diaphram BPVs are prone to tearing if intalled in the incorrect direction. For example, with the 710N, it is recommended that you install it with the spring loaded end facing the IC piping. I did it that way, and it has been very reliable.

**alen** · 07-29-2004 10:57 PM

you mean like this? in a 2000 1.8t.

**JMG** · 07-29-2004 10:58 PM

Am I not looking at that right or is the pic different from OEM? OEM position has the intake rerouting on the opposite side of the vac line.

Anyway, a Bailey in this position:

The vac line controls the pistion position. With the throttle closed the vaccume in the vac line opens the piston to allow flow to the intake return hose.

It's the same in reverse because all the BPV is a open/close switch. In vaccume the BPV is opened to allow flow to the intake return hose, but this time the flow will be reveresed. The resistance tests in DDQ's link tests which side has the most resistance. It is this side that should face the IC hose. This is in hopes that the greater resistance will hold more boost and also close faster, therefore result in less lag in boost recovery.

**JMG** · 07-29-2004 11:08 PM

Saturnine, I think you might have it reversed. The Forge and Strat DVs work best in the non-OEM reversed position with the spring loaded end facing the IC hose. This is the same for the 710N (like alen's). Stock, Bailey, and Porsche BPV's are installed in the OEM position.

With that said, it looks like the Bailey in the pic you posted should be turned around. It is currently in the reversed position.