can anyone tell me if the bov is supposed to close all the way or not? Its and 87 gxl with full t2 conversion, staight pipe from turbo to factory n/a catback, fcd, and home made intake. its not idleing very well, misses a lil bit at idle, when unplug the bov from the intake to make it atmospheric and plug off the intake the car wont idle at all unless i plug the end of the bov and then it clears right up and dont miss at all. i guess what im asking is, is my bov not functioning properly or is it supposed to leak air all the time???

 

The whole point of the BOV is to vent off pressurized air when you let off the gas. Aftermarket BOVs vent to atmosphere, so your stock one should be able to as well. What kind of boost are you able to reach with it constantly venting? It should be closed fully.

 

The valve is supposed to be closed at all times except when you let off the gas after boosting. When you let off the gas the intake after the throttle body becomes a large vacume instantly which in combination w/ the pressure built up by the turbo before the the throttle body pushes the spring in the valve to open. After pressure's balance it closes again. You probably have a bad or improperly installed valve. i doubt its installed wrong though but check where your getting your vacume from. I just helped my dad diagnose a Saab turbo that was doing the same thing. The customer was complaining about an odd sound which was the compressor surge from a non functioning valve.

 

i get to around 9 psi at full throttle, and if its supposed to close fully then i guess i need a new one, is it cheaper to go aftermarket?

 

No, it's cheaper to get a used one from a forum member. Cheapy ebay ones are around $30-50, and name brand aftermarket BOVs are $100+.

 

Get a nice aftermarket one it will make you smile lol.

 

yeah i think ill just go aftermarket, any suggestions???

 

Don't buy an aftermarket one.
Don't buy a used one.

Your BOV works just fine. Plug it in. The stock BOV is open at idle. If you unplug it, you now have a vacuum leak.

 

really??????

 

Yes, so when you vent it to atmosphere, at idle it is open allowing a decent size vacuum leak.

You probably have something else going on, like another vacuum leak, TPS out of adjustment, or in need of a simple tune up. The FAQ should contain help in figuring out idle issues.

 

True- the stock BOV is open at idle to bypass the turbo. If you want to opt for an aftermarket BOV, look into Synapse Engineering. They offer a top of the line BOV that is designed to function first and foremost. Try to avoid the cheaper BOV's as quality may not be as good.