Blow off valve doesnt work but turbo makes bov sound

[Thamobster1578]

it seems like forever now my bov has been making a weird noise so i finally decided to buy another one.after installing it it turns out its making the same noise.so i decided to hit the throttle under the hood and feel the bov and noticed nothing comes out of it.the bov sound actually comes out the turbo.even with the aif filter off.what would cause this.i checked all my vacuum lines and everything seems ok.somehow its tricked me and everyone who drives the car into thinking its been the bov the whole time but apparantly not.

 

[BigRand]

Fill out your mod list, and let us know what kind of BOV, sounds like its just not opening correctly.

 

[Thamobster1578]

mods are.built engine with 60-1 t3/4 .550 injectors.Safc. and all supporting mods.and the bov was an hks then i switched over to the greddy.neither of which are working ### the sounds coming out of the turbo

 

[VelocitàPaola]

That sound is just your blow off venting through the turbo (obviously)... For whatever reason, your BOV isn't opening - and the only thing I can think of is a kink or blockage in the vacuum line feeding it. Check the obvious. I know you said you checked the vacuum lines, but re-check them. Remove everything and blow through the lines...

 

[Thamobster1578]

yeah im gonna have to look into it.is there any damage this could cause. im guessing its bad since the bov isnt working but can this cause turbo damage or any other problems.thanks

 

[Blitzeclips]

Well I can tell you a buddy of mine ran into a problem with his HKS SSQ. While he was driving to work in his STi, apparently his BOV randomly stopped working. He came home and we took it off, everything looked just fine but we had a friend come by from a tuning shop to check it out. Sure enough, one of the diaphrams in it was bent, leaving it closed at all time. We were actually told that he has seen this type of thing before.. WTF

I'm not saying your BOV is defective, but we've had problems with it before.. somehow...

 

[BigRand]

If your BOV isn't working, then yes it could be bad for your turbo as you can hear that pressure surge sound (sounds hella cool thought right?), but its going to break fins eventually.

 

[Thamobster1578]

hey thanks for all the input guys.yeah i know the bov def isnt defective since im on my second one with the same problem.i just have to find out whats causing the problem now.im guessing its vacuum line related which sucks ### im awful with finding those problems.hopefully il figure it out ### i definitely dont wanna cause any problems to the turbo or anything else.thanks

 

[BigRand]

Get a spray bottle of water, or if your careful use brake cleaner. Lightly spray the vac hose, and if you hear a change in intonation from the engine then your close to vac leak, Just dont' spray too much as you don't want to suck too much water into your motor.

 

[destrux]

buy a vacuum gauge for $15 at an auto parts store and check for vacuum at the BOV vacuum line. If there isn't 18 inches of vacuum at idle then you have a leak in the vacuum hose, fix it. If you free rev the motor a few times in a row (and let off the throttle hard each time) the BOV should open each time you let off after the first time. If it doesnt and you have good vacuum then the BOV is bad, plain and simple. Some people mistake the sound of compressor surge for the sound the BOV makes. That may be what you're hearing. An improperly set bov (like a greddy, where it's adjustable) will also make the compressor surge noise, because it's not working right, even though it may be slightly working (not opening fast enough or wide enough because of a weak vacuum source like a clogged vacuum line). Compressor surge will kill a turbo with normal bearings, like a 16G or 14B, in a short amount of time usually.

 

[starfish]

Is it normal to here the bov when just driving around normaly(with out the boost gauge showing boost)?I can here my bov every time I shift,even when the boost gauge is showing vacume.Is that normal?My first turbo.Forgive me if this is a stupid question.

 

[VelocitàPaola]

Is it normal to here the bov when just driving around normaly(with out the boost gauge showing boost)?I can here my bov every time I shift,even when the boost gauge is showing vacume.Is that normal?My first turbo.Forgive me if this is a stupid question.

Yes, BOV's open whenever there is a pressure differential; positive pressure isn't necessary.

These types of questions have been answered before, please search more thoroughly before bumping old threads.