bov question

[nicku]

hi guys...
yesterday i tried to adjust my blitz dd bov spring because I think i had a little boost leak. the car has a little hesitation between 3500-4000 rpm. so i tried to retight the intercooler piping and tighten up the spring on the bov a little bit. I actually dont know how tight is tight. and thats the first question i have. how tight on the bov is tight?
the second question, i noticed that today. after i tight up the spring, my idle became leaner, is it because of the spring is too tight? or something else? my idle was between 13-low 14. now is high 14 to low 15. might it be the spring is too tight?

[punxva]

tight is when it doesnt open...

[nicku]

i mean, how tight is it supposed to be? and if it is too tight, does it cause the car running a little lean?

[SoSideways]

i mean, how tight is it supposed to be? and if it is too tight, does it cause the car running a little lean?

Uh, no?

You know it's too tight when you are at full boost at redline and let off, and the BOV doesn't open.

[boofa]

right, the BOV shouldn't effect your idle... it's only when air pressure is increased after acceleration.. that the BOV is opened to release it into the atmosphere. during idle, ur BOV is closed and the spring has nothing to do with ur idle.

[nissanguy13]

right, the BOV shouldn't effect your idle... it's only when air pressure is increased after acceleration.. that the BOV is opened to release it into the atmosphere. during idle, ur BOV is closed and the spring has nothing to do with ur idle.

Correct me if I'm wrong but if the BOV is too loose then it's the same concept as a vaccum leak isn't it. Since the air can escape withouth the pressure opening the valve?

[Boosted240Guy]

All i know is if the BOV is too loose it will open even if your only at like 2,000 rpm. I had a turbo XS bov for a while that was leaking real bad and my car would just stall out and it was just bad. Now im running a Saard R2D2 and it's amazing. Anyway though, if you think it might be leaking, put some water and soap around the bottom of the valve where it's connected to the Flange, and if it starts bubbling up then it's leaking. and if you think it's too tight, look at the directions for it and see what they measure the turns for tighting it in. Mine was half turns of the bolt so 2 full turns was 4 times tightened....it can still be too tight even if it's still releasing....hope that helps a little

[Pepperoni]

Correct me if I'm wrong but if the BOV is too loose then it's the same concept as a vaccum leak isn't it. Since the air can escape withouth the pressure opening the valve?

Yes that's only correct when you're NOT recirculating your BOV back to your intake.

And to everyone else: I don't know about knock off BOVs and their quality, but the spring is only there to adjust preload on your BOV spring. It should be adjusted to the lightest level possible while it still holds your BOV shut in high vacuum. It's a common misconception that the spring holds the BOV closed while in boost. Actually it's boost itself that holds the BOV shut. What do you think the hose you connect your BOV to does? It changes the pressure conditions and your BOV will open/close depending on the situation. So basically the spring you're adjusting is to hold the BOV closed when your throttle body plate is closed (idle/decel). If you're recirculating your BOV, you won't notice anything unless you're running an atmospheric BOV. The reason I say it's best to adjust it to the lightest level possible (while still being able to be closed in high vacuum conditions) is because if you tighten it too much, then the BOV won't be able to snap open as fast/completely and you may end up getting compressor surge, which defeats the purpose of even having a BOV in the first place.

Oh, and if your BOV really is leaking during boost, it's probably either a shitty BOV or is damaged. Usually the BOV will leak under boost if the membrane that lets the BOV piston move is damaged. There's usually two seals and if either seal is damaged then it will leak under boost.