Bov Operation?

[A//// Guy]

So Im driving my car in blow thru mode (91 gsx) and I just redid it to that setup. At idle is there supposed to be slight airflow coming out of the BOV outlet? or only under boost. I have a new vacuum leak since I redid a couple things this past couple weeks. It used to read 18-19 at idel but now its like 17-18.

I havent put pull boost down yet but when it was hitting like 2-3 psi and let off the throttle the BOV didnt woosh as normal is just kinda made some fluttering noise. Is this because its cold or what?

I did have it beadblasted at work so I could paint it, and I sealed it all up , nothing got inside.

[john]

What kind of bov? If it were my car, I wouldn't care about a vaccum difference of 1hg. That could just have something to do with the temp. I bet your car still idles perfectly fine. Maybe your bov is leaking.

[A//// Guy]

Yea I figured out the vacuum. When I switched to 550s I also switched the Translatro for 550s which made everything super lean. I have idle cranked up to +20% on the AFC. Once I richened it up the idle jumped +300-400 rpm and then I lowered it and the vacuum was normal (18-19)

But my (stock) BOV is making some weird noises. It flutters and makes a groaning noise when you let off the gas after boost.

[1ViciousGSX]

There should not be any airflow coming out of the BOV at idle, only when it opens to relieve boost pressure.

[A//// Guy]

Great now I have a shitty BOV. Anybody recomend a cool sounding one? I like the stock but it squeaks and makes weird noises even when normal.

I dont want to spend more money. ;(

[CVD]

It is perfectly normal for it to suck in air at idle. The BOV is before your MAF right?

I know this seems obvious, but did you hook up the vacuum line? The stock bov flutters sometimes, but it's not very common. Usually that flutter is asociated with BOV-less turbo cars.

Mike at QPR has a device that he can hook up to the vacuum fitting on your BOV to test it and see if it will open. That would be another good thing to try.

[A//// Guy]

I hooked everything up right and the BOV doesnt suck air into the valve it blows it out as it would when it lets out boost.

When I was cleaning it I could push the valve inward if I pushed really hard.

Yea the BOV is before the MAF. I dont think this is how it performed before I painted it and blasted it so maybe some stuff is stuck in there.

[CVD]

That is very strange. It would take some funky voodoo shit to get a bov to blow out air at idle.

Being able to push the spring isnt the same as hooking up a vacuum line to see if the bov still works properly.

[Shane@DBPerformance]

Well, 19" of vaccum is a little high for DSM at normal 750rpm idle. They usually seem to be closer to 16-17". The vacuum is so high that it is probably sucking the BOV open. BOVs open at high vacuum(like after a shift), if your is very high at idle, it can start to open the valve.

[Matt D.]

Regardless, if the BOV is opening under vacuum conditions it is only sucking in air, not blowing it out.