BOV question?

[danyz250f]

My bov is funny sounding. I am venting via maft. When i boost and let off no matter what level it will flutter. So if i let off and coast dont hit the wot it will be like WHHAAAAAP (engine spooling noise) PSHHHH FWA FWA FWA FWA (BOV noise) why would it doo this it used to be a hard normal psshhhhh noise like normal. Is my bov worn out? I am also running like 17 psi. The bov has about 235,000 miles on it. My car has 112,000 miles. I cracked mine bolting it on once.

 

[Talon-96]

Jeez 250k Id say worn out

 

[oldman]

Tapping the BOV line for your mbc can also create similar issues.

 

[danyz250f]

It didnt do it before just started. My bov vac goes straight from the stock tap to the top of the bov. My mbc goes from my j-pipe to waste gate.

 

[Talon-96]

Check all the lines for leaks and think about using the compressor housing for your mbc instead. But i would say it is worn out and you could use a new one anyways.

 

[danyz250f]

I think I might try my friend greddy knock off. If I can get it not to leak i will take it from him. I has been like a month since i last leak tested it so I am due. My car runs super strong if I could get my logger to work I would try more boost.

 

[MrBoxx]

Did your friend replace the diaphragm of his knockoff with a real Greddy diaphragm? If not, you may end up having to. It's about $60-70 at some vendors, if I remember correctly.

 

[brute]

The fluttering noise is compressor surge, which means your BOV isn't opening enough, if at all. I'd check the vacuum line running from the BOV to wherever you have it hooked in to (should be the intake manifold). The hose might have a hole in it, not only making your BOV malfunction, but also a boost leak.

 

[AsILayDying]

I have the exact same problem. It started doing it two days ago, when I hooked up my MBC. I didn't know whether it was a bad thing or not. So this means there is a boost leak? I'll look for a hole or see if i did something wrong with the Tee in the BOV line to the Intake Manifold.

 

[MrBoxx]

Don't tap your BOV line for an MBC. Use a nipple on the compressor outlet or J-pipe. If your MBC is a bleeder-style MBC, you've created a default boost leak in the BOV line, which will affect the operation of the BOV.

 

[oldman]

I have the exact same problem. It started doing it two days ago, when I hooked up my MBC. I didn't know whether it was a bad thing or not. So this means there is a boost leak? I'll look for a hole or see if i did something wrong with the Tee in the BOV line to the Intake Manifold.

Tapping the BOV line for your mbc can also create similar issues.

The wastegate pressure relief hole on the mbc is the hole you're looking for.

 

[oldman]

Don't tap your BOV line for an MBC. Use a nipple on the compressor outlet or J-pipe. If your MBC is a bleeder-style MBC, you've created a default boost leak in the BOV line, which will affect the operation of the BOV.

Eric, the wastegate pressure relief hole on ball/spring type mbc's will do the same.

 

[MrBoxx]

I forgot the ball/spring types also have a relief hole, then remembered a post where two people were arguing over how it works. Thanks for reminding me.

 

[oldman]

I forgot the ball/spring types also have a relief hole, then remembered a post where two people were arguing over how it works. Thanks for reminding me.

Yes I saw that one also and didn't want to get involved because there are just too many factors involved. The size of the bleeder hole, design of mbc, fittmentship .........etc. The fact that the entire argument was based on the theory that a metal ball pitted against the casing by a spring without gaskets will seal against pressure air just kinda makes the thread even more confusing. I can tell you that my mbc starts to leak at 1-2psi during a static pressure test.

 

[destrux]

If you do get a greddy knock off, take it completely apart and make sure it's put together right. I just got one and the nut inside that holds the piston in was just barely started, wasnt threaded even halfway on. After I went through the BOV and cleaned the metal chips out and tightened everything right it works great. Just make sure you have a good vacuum source or it will flutter like crap instead of venting with one good whoosh.