Leaking Stock 1g Bovs

[Nelsons91AWD]

my friend has new intercoooler piping flanged for a 1g BOV recirculated back into the intake.

He has his external wastegate set at 7 PSI and can only build 4 PSI.

When we pressure tested the system air was coming out of the blow off valve, so we thought the valve was bad so we replaced it.

its still doing the same thing, its not leaking out of the gasket area, its leaking out of the actual open nozzle.... SEE BELOW

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Any Ideas????

 

[pooker]

Is the vacuum line running to a proper source from the bov like the intake manifold? It could be a possibility that both are wrong but that seems unlikely at this point.

 

[BigPapa240sx]

The vacuum source I'm using is the Brake booster line. I was thinking of crushing the BOV, and seeing if it would hold the boost then. What do you guys think?

 

[Talesin]

That sounds rather stupid and dangerous. Turbo DSMs have a dedicated pressure nipple from the intake manifold to the CBV. It should not be teed into. And your brake booster line sure as hell shouldn't be teed into.

When doing your boost leak check, make sure that your throttle is open, so the pressure can get in and pressurize the CBV feed line. It needs pressure on both sides to stay closed... kinda like your ear when you go up a hill, it needs to equalize. At that point the CBV should stay closed.

And unless you're on an aftermarket turbo or wastegate, you're not going to see 7psi, other than from the stock gauge which lies. OEM wastegate spring pressure is 10psi actual. With a real boost gauge, that'll be visible. The stocker is just a guess by the ECU as to what the pressure is, based on engine RPM and intake flow numbers from the MAS. It will NOT give you accurate boost numbers. That's why the first mod on the tech list is an aftermarket boost gauge.
On the up side, it makes it easy to guess when someone doesn't have one. They always think their car's boosting at 7psi.

 

[BigPapa240sx]

This is a custom setup on a 240sx running 7psi from a turbonetics evolution wastegate. I think i will try a different vacuum source first.

 

[Nelsons91AWD]

This is a custom setup on a 240sx running 7psi from a turbonetics evolution wastegate. I think i will try a different vacuum source first.

Yep that is correct...

 

[SBstar]

Just to add my 1g bov started leaking the same way at 5psi, I put in a Forge BOV and it doesn't even think about leaking like that. I crushed one of my 1g bovs as well to see if it fixed the problem and it held until about 10psi and started leaking again. (I had two and both did the same thing) The Forge BOV is still holding strong with as much boost as I can throw at it with the 14b.

 

[Nelsons91AWD]

So we are going to try to crush it and run a different vaccum source to see if it solves the problem.

Any other ideas in the meantime?

we will keep yall updated.


thanks

 

[BigPapa240sx]

Yeah, I only plan on running 7psi, so if crushing it holds that without leaking, that'd be fine.

 

[turbo16]

Mine is crushed and starts leaking around 5 psi slightly. You might as well crush it, see if that helps you out, if not get an aftermarket one.