Possibly a bad 1g BOV?

[LegacyCore]

Installed a used crushed 1g bov on my 2g Eclipse today that I got off ebay from a guy who ran it at 22psi on his Talon. At first everything was working fine, except for the fact when I hit boost I would spike around 20psi. I tried lowering the pressure with an NXS MBC, but it never made a difference. It would spike around 20psi and hold around 18psi. Then on the final attempt I accidently took 2nd gear to 7500RPM and the car backfired. I noticed right after that the 1g BOV stopped opening and I would get compressor surge.

After getting back home I checked all of my vacuum lines, checked for boost leaks. But found none, but then I noticed while at idle if I blipped the throttle the BOV whistled. So I then removed and capped the vacuum line from the intake manifold to the BOV and blipped the throttle again. This time no whistle from the BOV. I've heard of some 1g BOV being slightly open at idle on a 2g. I'm assuming that is why it suddenly started to whistle...

So I reinstalled my 2g BOV and removed the MBC taking it all back to stock, and everything is running fine now.

So here is what I was wondering. Is it possible that the previous owner of the 1g BOV crushed it to much? And at lower boost levels there is not enough pressure to open the BOV? Thus why I was spiking at 20psi after installing the crushed 1g BOV?

What else can cause this issue?

 

[bryanwheat]

Installed a used crushed 1g bov on my 2g Eclipse today that I got off ebay from a guy who ran it at 22psi on his Talon. At first everything was working fine, except for the fact when I hit boost I would spike around 20psi. I tried lowering the pressure with an NXS MBC, but it never made a difference. It would spike around 20psi and hold around 18psi. Then on the final attempt I accidently took 2nd gear to 7500RPM and the car backfired. I noticed right after that the 1g BOV stopped opening and I would get compressor surge.

After getting back home I checked all of my vacuum lines, checked for boost leaks. But found none, but then I noticed while at idle if I blipped the throttle the BOV whistled. So I then removed and capped the vacuum line from the intake manifold to the BOV and blipped the throttle again. This time no whistle from the BOV. I've heard of some 1g BOV being slightly open at idle on a 2g. I'm assuming that is why it suddenly started to whistle...

So I reinstalled my 2g BOV and removed the MBC taking it all back to stock, and everything is running fine now.

So here is what I was wondering. Is it possible that the previous owner of the 1g BOV crushed it to much? And at lower boost levels there is not enough pressure to open the BOV? Thus why I was spiking at 20psi after installing the crushed 1g BOV?

What else can cause this issue?

It is more likely that your 2g bov is just leaking and with a sealed bov you are actually making 18 psi. The bov should never open while you are under boost. It's job is to stay closed until you remove your foot from the throttle and vacuum is present at the source line.

 

[Dxc545]

What psi are you originally shooting for? It could be crushed more then you need and would cause compressor surge. The more its crushed the less effective it is in the lower boost range

 

[northernawd]

You said you tried to lower your boost with an mbc, but what spring do you have in your wastegate? That spring will control your minimum boost level. Your MBC might be turned down further than what your spring is for

 

[LegacyCore]

Thanks for all the replies everybody, just to start off I do understand how a BOV works. I know during acceleration and building pressure the BOV is supposed to stay closed. But when I let off the throttle is when I'm getting compressor surge.

And in regards to the boost level I would like to achieve I've done some research and I find that an otherwise stock 2g on a 14b is good around 16psi. So if I could get somewhere in that neighborhood I'd be pretty happy! That is until I need to start worrying about bigger injectors, fuel pump, and purchasing a new ECU capable of link.

My 14b is stock off of a 1g DSM I've not modified or ported it in any way. So the spring in the WG should be whatever it is from factory!

I also tried removing my MBC and plugging the vacuum lines back into the factory controller in the engine bay. I still could not get the 1g BOV to open be it at 5psi or 10psi. So I was forced to reinstall my 2g BOV so I could safely drive the car without compressor surge. The car with the factory boost controller, and the 2g BOV on the 14b is reaching and staying steady at 12psi.

I also would guess that the previous owner who crushed the 1g crushed it to much, and at lower boost levels there is not enough pressure to open the BOV. Any other ideas or suggestions?

 

[Dxc545]

You could hook up a vacuum pump to the nipple and see when it opens. I think its incorrectly crushed