1G BOV leak during BLT

[NeMiZiS]

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Doing a boost leak test before I attempt more tuning. It seems at about 15psi my BOV is opening. Does it mean the diaphragm is leaking? Or is it possible I ran a vacuum line wrong?

 

[kmetiuk]

Unfortunately, the 1G BOV's do leak after a certain point due to their design.....and also they are 20+ years old now so they prolly wont hold as much as they once did.

I have run 3 different 1G BOV's....

1st one was a crushed by mean and was good upto about 25 psi and then it would only leak a tiny tiny bit. I ran it at about 18 psi for a year-ish and then suddenly wouldn't hold more than 5-8 before cracking open a bit.

2nd one was a crushed by someone else and wouldn't do more than about 20 on a test but held 18 fine.... about 6 months-ish.

3rd one was unmolested and wouldn't hold more than about 12 psi....at this point I figured if I keep buying 1G BOVs after a few more I coulda just bought a decent tial or something.

I ended up with a Synapse Synchronic BOV which will hold 100+ psi on a bench test from with a compressor.

The main issue with the 1G BOV is its push type meaning its got a spring holding it down like a wastegate does. Exceed the pressure its designed for and it will open. That's why peeps crush them, it squeezes that spring down harder to hold more boost.

The thing a like about the Synapse is its a pull type meaning the more boost you have the harder it seals. Never have to worry about it leaking again....plus its built with O-rings you can just buy at the local hardware store so rebuilding its a breeze if it does happen to leak due to worn seals.

 

[007jimmy]

Maybe it's time to bite the bullet and pick up a new bov. Sure you can crush it and squeeze out a little more but you are also compromising part throttle operations. It won't open as easily and causes airflow to come out the compressor housing possibility damaging the turbo.

 

[mitsubishikid]

I'd recommend you get a nice after-market bov, I've been looking at the NGR units myself.

 

[pauleyman]

Why don't people pressurize the vacuum line whenever a boost leak test is performed? Under boost there is pressure on the top part of the diaphragm. From what I have seen in a typical boost leak test there isn't

 

[RipperXX]

Why don't people pressurize the vacuum line whenever a boost leak test is performed? Under boost there is pressure on the top part of the diaphragm. From what I have seen in a typical boost leak test there isn't

This right here! With the top line disconnected my 1g recirculation valve aka bov will open around 8-10psi. But connect the top line to the intake manifold and allow boost pressure to go to the top as it would while driving and it holds 18psi before cracking open.

I recent just got a Evo IX unit as it should be stupid easy to swap out. They reportedly hold 25psi fine...someone slightly crushed the unit soo probably more. And it only cost me $90 off e-bay....and it's still a Mitsubishi OEM part that maintains the "quick open" function.

 

[NeMiZiS]

Thanks for the replies.
I have a few other BOVs I can swap it out with.
Will swap it out and give it another try.
The line going to the nipple on the BOV is hooked up, only thing not connected is BOV recirculating tube.

 

[murr1979]

This right here! With the top line disconnected my 1g recirculation valve aka bov will open around 8-10psi. But connect the top line to the intake manifold and allow boost pressure to go to the top as it would while driving and it holds 18psi before cracking open.

I recent just got a Evo IX unit as it should be stupid easy to swap out. They reportedly hold 25psi fine...someone slightly crushed the unit soo probably more. And it only cost me $90 off e-bay....and it's still a Mitsubishi OEM part that maintains the "quick open" function.

My issue I'm having is I'm getting pressure from the vacuum line going into BOV when I pressure tested my system. I pressurized the system with 5psi and I get air coming out of the end of the vacuum line. I know I have a boost leak and I don't think that's normal. Does anyone know why that would happen?

 

[Brembo]

Is it me or something is wrong. You disconnect the hose from the bov during blt and you complain that it leaks? I don't disconnect any hoses during blt and it's holding fine. I did crush the bov and it leaks a little internally from the seal on the shaft but other then that it's good to go. The best saying I read on this boards goes like this: crush it and calibrate it with a hammer. I just crush it and monitor during the crush with vacuum pump to see when it cracks open. Holding like 25 psi now. Now drivability has degraded do to bov but it is what it is.

 

[Brembo]

Take a picture of the line you talking about

 

[murr1979]

Take a picture of the line you talking about

I'm sorry we're you talking to me? I'm new so just realized the post I was replying to was a while back and I had a thread deleted for thread jacking. Apparently that's a thing. So don't want to don't again. Wasn't complaining but yes the BOV leaks due to air coming through that vacuum line. The question I was trying to get answered was should air be coming through that tube/vacuum line going into the BOV and I found out that it's supposed. It's a basic question but I didn't know. I unplugged it just to make sure it was coming from there and not through the bottom of the BOV.