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In theory it should handle any boost level I would have thought. The valve has the same pressure on both sides of it at all times when your on boost.

Only when shifting can it be a problem, and event then the down side is that the bov doesn't flow enough to allow it to stop a pressure spike back through the intake plumbing and reducing turbine speed.

ive been told the standard bov will leak at 14psi, when i got my car tuned by hitman he said i had a boost leak somewhere and all of my pipes were perfect.

i bought a 2nd hand gtr bov which can handle way past 1 bar :)

Does the gtr bov bolt up with no mods or?

I recently blocked the std bov's bleed hole and boost went up a psi.

GTS4Newbie,

Only when shifting can it be a problem, and event then the down side is that the bov doesn't flow enough to allow it to stop a pressure spike back through the intake plumbing and reducing turbine speed.

Give this a shot.. Block your bov off. Run no bov.

Take it for a drive and experience your turbo doing the exact opposite as to what you suggest. The car really does get up and go much quicker after a gear change when running no bov.

My own thoughts are that yes there is a pressure spike but not having the bov release the pressure essentially prevents the lag that you experience with a bov when the turbo has to spin up and fill the ic piping and fmic again. With no bov the majority of the air is still there so the turbo quickly spins up a little and is up on boost quicker.

This is what I experienced. Give it a shot. :)

I did however experience a horrible jerky driveability issue when changing gears at part throttle and low rev's. Changing up at 3500rpm or so and driveability was fine.

I also had the odd stall under certain circumstances but nothing I couldn't work around.

The results with the blocked off bov were that good that I'm tempted to put up with the jerkyness when changing up at 7psi or so with part throttle at 2000rpm. It really did feel like it was instantly on boost when grabbing the next gear.

Anythin above 15psi the bov will leak and not do its job!

My changes are so much smoother with a decent bov + plumback section set up, mind you i do run 20psi through a bigger turbo which is producin alot more air-flow than the stocker would!

If you are runnin 1+ bar id change it even on stock turbo...

If you are runnin 1+ bar id change it even on stock turbo...

If your running 1+ bar on a stock turbo, you'll need Gilly out back to catch that turbo wheel!

I have heard of several stock GTS-t BOVs dying on not much more than 12psi so I would upgrade to GTR or aftermarket for 1bar+.

Well guys i run the stock GTR plumb backs, and i boost nearly 2 bars. so the GTR BOV does its job in my application, it flows enought to take 23psi of T04Z pressure, cuz i dont get any surge issues.

My son and I tested his stock BOV on his R33.

We made up bungs, plugs etc, removed the BOV recirc. pipe and pumped up the complete inlet pipework including FMIC to 2.0+bar.

Results were fine. Just a slight leak which remained at 2.0bar or 0.5bar.

Then we swapped the BOV for my old R32's one and exactly the same story.

With ingenious valving we snapped the BOV open and shut and the tiny amount of leaking continued, it's only a metal to metal valve seat after all.

At 1.3bar, his 2835 had heaps in reserve to more than compensate for the BOV leak, but if you're pushing a stock turbo to 1.0+bar, you'll have more to worry about than a BOV leak.

Did you plug up the std bovs bleed hole?

No, the BOV was as installed but with the recirc. hose off so we could gauge how much air was leaking.

I run a std r33 bov on my car which runs up to 20psi. Its simple physics unless the bov is completely f**ked it cant possibly leak. The plenum side has pressure on a larger area than the pre-throttle body pressure, it cant leak.

there are benefits of leaving that hole unblocked. 1 is that when at WOT there is a small amount of air being released through it back into the intake. this negates a vacuum effect happening which would suck the bov open at higher boost pressure.

hrmm not so sure on that theory Mad082.

If there was enough vac to over come the spring pressure + the added equalised boost pressure some thing would be quite wrong with the intake pipe.

From my own experience all it does is smooth out throttle making it nicer to drive, with the blocked its very on/off and can cause a bit of a jolt under certain circumstances.

With it blocked it makes boost earlier and without touching anything else it makes 1psi more once on boost.

It also won't release the bov when making boost at say 1/2 throttle then backing off to 1/4 throttle, the turbo just keeps boosting, very noticeable driving up hills as its difficult to keep off boost where as before cruise up a hill and providing acceleration was steady it would be off boost.

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