Where Can There Be A Leak In Bov System?

[Kwyjibo]

I have a basically stock R32 gtst, only real modification is 3" turbo back exhaust. It currently runs at a bit over 11psi. The back of the car gets really dirty after about a week of driving, I had a friend drive behind me and the only smoke he could see was a puff of black smoke whenever I backed off. My car has also been backfiring sometimes when I back off.

Anyway I found out that the standard BOV had been blocked off at the crossover pipe, which is the most likely cause of this(coils and plugs are basically new, no misfires).

The problem is whenever I remove the piece of metal blocking the BOV the most boost my car will run is 9 and that is only for a split second and it drops off to 8. I have tried it with another BOV that was working fine on another car and the same thing is happening.

Where would there be a leak? The only place I can think of is BOV > intake piping(after AFM), but I wouldn't have thought this area would hold boost anyway since it goes right out to the filter. Could it be the vacuum hose leaking that leaves the BOV open or something??

Thanks for any help.

Adrian

Edited August 18, 2007 by Kwyjibo

[BHDave]

The factory bov has a bypass in it to make the operation a bit smoother. That may be causing your loss of boost (though 2 psi does seem excessive). You can mod the stock bov to block up this hole.

You haven't introduced a leak when changing bovs have you? and it is plumbed back right?

[Kwyjibo]

Well I figured that but I also remembered the BOV I borrowed had a screw in the bottom of it(which I understand effectively blocks off that leak). Either way it should still be running at least standard RB20 boost, not 8. Yeh it is plumbed back into just after the AFM.

[Cubes]

The back of the car gets really dirty after about a week of driving

All bets are on having a gutted or no cat.

Backfiring is caused by the blocked off bov.

If the cat isn't already gutted my bets are on it being stuffed due to the backfiring etc.

Have you connected up the pressure feed to the bov correctly? It may be that its blowing open a touch if its boost feed isn't connected.

Block the bov back off; use a coke can, chop it up and see how u go. If it holds boost then the problem lies with the bov.

[Kwyjibo]

Have you connected up the pressure feed to the bov correctly? It may be that its blowing open a touch if its boost feed isn't connected.

Block the bov back off; use a coke can, chop it up and see how u go. If it holds boost then the problem lies with the bov.

Yeh I've put the piece of metal(it probably was a can of some sort) back in a few times and each time it fixes the problem. Another BOV didn't fix the problem. I'll check the pressure feed but it looks fine to me. Any idea how to check if my cat is working?