GReddy Type S BOV question

[jersey_emt]

My GReddy BOV lets out a slight whistle sometimes when I am off the throttle...I think it may be leaking, because the whistle sounds like the tail end of a full blow-off.

If I tap the gas, or sometimes if I disengage the clutch, the whistle goes away. But it returns if I take my foot off the throttle.

What could be the cause, and any suggestions on how to correct it?

 

[jersey_emt]

bump 9 views and 0 replies

 

[DSMConvert]

are you positive its your BOV that is making the noise? if it is have you checked the spring or seen if the screw in the top is loose? could be a million things which is why no one is replying hard to nail a problem when all you say is that your car whistles when you let off the gas...

 

[mp5jeff]

why don't you try adjusting it to see if it still does it?

 

[jersey_emt]

Checked all hoses & pipes, no vacuum leaks.

Adjusted the BOV looser, did not get rid of the whistle.

 

[PaulMP3]

My GReddy BOV lets out a slight whistle sometimes when I am off the throttle...I think it may be leaking, because the whistle sounds like the tail end of a full blow-off.

If I tap the gas, or sometimes if I disengage the clutch, the whistle goes away. But it returns if I take my foot off the throttle.

What could be the cause, and any suggestions on how to correct it?

Does it whistle when letting off, or when you are just idleing off the throttle?

 

[jersey_emt]

Cruising when off the throttle.

 

[PaulMP3]

you try tightening the top screw/nut?

 

[jersey_emt]

you try tightening the top screw/nut?

The screw with the hex head or the nut around it?

The nut is pretty tight but could probably be tighter...i guess I'll try that tomorrow.

 

[PaulMP3]

The screw with the hex head or the nut around it?

The nut is pretty tight but could probably be tighter...i guess I'll try that tomorrow.

yea, tighten that.. you need an allen wrench for the inside screw, loosen the nut then turn it in.

I find it makes a louder noise when in further. To far in, and i get slight compressor surge. My car sounds like a dog barking, not a turkey though.

Play around with that screw to adjust it, probally will sound a lil louder too.

 

[jersey_emt]

Yeah it's still not stalling out if I rev and shift to neutral...plus I get a touch of turkey if I shift below 3500rpm, so I'm going to loosen the spring a bit more, and really tighten down the nut and see what happens.

 

[ylmazdaspeed]

If you got the type s it will make that whistle. By loosening the nut and using an allen key to thread in the thread shaft further is tighten the spring which requires more pressure on teh valve to open. The way to properly adjust the BOV is to tighten the threaded shaft enough so that there is no leak at idle. When you rev the motor and let off, the bov will open and should shut without leaking. I had the type s on the turbo honda and it sounded the same. From my experience it's normal for that BOV to have a slight whistle. Word of advise, don't tighten the threaded shaft too much or that valve won't open enough to vent.

 

[jersey_emt]

If you got the type s it will make that whistle. By adjusting the nut what you're doing is making the valve require more presssure to open to vent the air left into the charge pipe. The way to properly adjust the BOV is to tighten the nut enough so that there is no leak at idle. When you rev the motor and let off, the bov will open and should shut without leaking. I had the type s on the turbo honda and it sounded the same. From my experience it's normal for that BOV to have a slight whistle. Word of advise, don't tighten that nut too much or that valve won't open enough.

So you're saying: tighten the nut a little bit at a time until the whistle @ idle goes away, but if it gets to the point where it's really tight and the whistle is still there, then just live with it?

 

[ylmazdaspeed]

So you're saying: tighten the nut a little bit at a time until the whistle @ idle goes away, but if it gets to the point where it's really tight and the whistle is still there, then just live with it?

Sorry I had to rephrase my wording there is but tighten the threaded shaft enough so at idle theres no leak from the BOV. Rev the motor up, the valve should open and shut promptly. If theres still a leak that occurs tigthen the threaded shaft alittle more till there is no leak. Tuning a BOV is not tuning it to sound how you want it, it's to tune it so it functions properly and does it's job. If I had a scanner I could show you the bov tuning instructions greddy provides.

 

[jersey_emt]

OK then..correct me if I'm wrong:

So the nut around the screw doesn't really affect anything then...it just keeps the screw from moving.

So I should tighten the BOV more (turn screw more towards 'hard') to get rid of the whistle?

 

[CustomMSP]

My mitsu BOV vents at cold idle...is that normal? Sorry to sort of thread jack

 

[ylmazdaspeed]

OK then..correct me if I'm wrong:

So the nut around the screw doesn't really affect anything then...it just keeps the screw from moving.

So I should tighten the BOV more (turn screw more towards 'hard') to get rid of the whistle?

It's not about the whistle. No matter how much you turn the threaded shaft in you'll still get the whistle. Less as you turn it in because now the valve requires more pressure to open. Less it opens, less whistle and welcome back compressor surge. (doh)

Basically play around with tightening and loosening the valve, until you're happy thats where to set it.

 

[ylmazdaspeed]

My mitsu BOV vents at cold idle...is that normal? Sorry to sort of thread jack

BOV should stay shut until theres enough pressure to force the valve open. Not too sure what the stock Mitsu BOV are set at.

 

[Got_boost02]

i think you're gonna get this slight whistle no matter what if its tuned at idle like it should be. if it is tuned at idle it is close around -20in, when your cruising down the highway and you let off the gas, your vaccum will drop a couple of more inches thus cause the bov to open slightly given you the whistle. i have the type s and i know exactly what your talking about, but i dont think there is any way to get around it. it might work if you tighten it but i think you'll get compressor surge, at least thats how i experienced it? i dunno, jut my thoughts

 

[jersey_emt]

Thanks guys, I guess this is normal. I tried tightening the valve, and the whistle went away, but the compressor surge came back. So it's back where it was, with the minor annoyance of a whistle...I've found that *extremely* light pressure on the throttle gets rid of it and doesn't affect your coasting.