Bov Sound

[SargeRX8]

I have NO idea what is causing this sound. I made a thread about it a while ago on my old car about a weird squeel at certain rpm. My new car didn't do it..... Until I swapped off the atmo BOV for the standard nissan BOV the f**king sound came back! Its like a EEEEEEEEEEEEEEEEEEEEEEEEEEEEE sound which will just maintain it self if I can locate the RPM its produced at. So what I mean, if the sound occurs at 2000rpm, the sound will finish as soon as I get to 2100 rpm. but if I hold 2000rpm it will keep going until i let go or go a little faster.

What the hell is it? Is it a failing BOV? Is it a leak?

[Trozzle]

Unlikely to be the BOV. The BOV would only fail at a certain pressure if it were faulty, not an RPM. Because of this, you would be able to replicate the sound at a certain throttle point for any given RPM (not guaranteed).

I'd be thinking check your belts.

Does it make the sound at 2000rpm when the car isn't moving in neutral? If so, pop the bonnet and rev the engine by manually opening the throttle body with your hand. Find the point where it makes the sound, and try to work out where it's coming from.

[SargeRX8]

Only when in gear and only if I hold certain pressure. If I'm rolling down a hill a 2krpm it wont make the sound, but if I pushing up a hill at 2krpm it will make the sound. It is only if there is pressure. If I remove the BOV and fit my atmo BOV back on, the sound is gone. It made exactly the same sound in a completely different car(the exact same BOV).

[Trozzle]

Yeah I'd say it's the BOV then. The GTR BOV I'm running makes a very slight whistling sound if I hold it at the point where it's open but not off throttle yet.

[Rolls]

block the bov off with a piece of coke can and see what happens, you'll get annoying as f**k flutter but if it gets rid of the sound you are talking about then it means it is the bov failing.

[Luciano]

^ if blocking it doesnt get rid of the sound, also take a a look at the gaskets and studs around the exhaust manifold and turbo area. I had a couple of broken studs and a chunk of exh manifold gasket missing. Made a real high pitched squeal all the way to redline when on boost. drove me fkn insane...