Whistling Noise

[L36 SS]

This happens under wot and noticed it about a week ago. Sounds to me like a vac leak but I checked around for leaks but couldn't find any. Suggestions?

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[TommyGloves]

Hopefully James will chime in.

(I should have time next week to scan your car if you want to stop by one night.)

 

[TommyGloves]

Did you install your boost guage? How's the vac & boost readings?

 

[L36 SS]

cool thanks. Vac reading are around 17-20 and boost is at 6psi.

 

[L36 SS]

Which is low for my setup from what I hear.

 

[ldyzluvdis06]

 

[Turbocharged400sbc]

sounds like a post blower vac/press leak...prob somewhere along the SC gasket since it can act ike a reed.
you can do a combustible spray test but if the vac leak is like some ive seen it leaks less under vac than it does under pressure. not to mention make damn sure your ignition cables are in good shape as 3800's seem to not mind looking like a lump of charcoal if ya let em
if you dont have access to a vac/evap leak smoke machine to test with the engine off, you have a couple options...
blowing cigarette smoke with the rad fans off and no air movment might let you see the vac leak drawing it in.
you could do the same test brake tqing it to pressureize it to see where it can be blowing the smoke away.
if you already checked that everything is tight, you can loosen sc/rails/etc mounting bolt 1/2 to full turn and test drive till you hear the tone of the whistle change (retighten before doing the next bolt)

 

[L36 SS]

Thanks James, i'll take it in to get the smoke machine hooked up to it.

 

[Turbocharged400sbc]

dont be a pussy, grab a pack of smokes and make like a chimney

 

[L36 SS]

Haha, i checked the blower bolts and the 1 in the back had backed out some. (the one that wouldn't bite during the install). Got a slightly longer bolt and got it to bite.

 

[L36 SS]

Well the noise is still there...james I heard that the bbv could not be closing all the way..could this be true?

 

[TommyGloves]

I have a spare BBV you could try out. Might also be the reason why you're seeing lower boost readings...although with your mods it might be right.

 

[b4black]

I have a similar whistle after installing an IC. Seems to do it at part throttle and not WOT. Whistles at about 2-4 psi. At WOT, I have seen as high as 13.2 psi on the DIC with a 3.2 pulley.

 

[L36 SS]

I have a spare BBV you could try out. Might also be the reason why you're seeing lower boost readings...although with your mods it might be right.

Was seeing 7psi on the way home tonight..so im sure that's normal. Did you get my text?

I have a similar whistle after installing an IC. Seems to do it at part throttle and not WOT. Whistles at about 2-4 psi. At WOT, I have seen as high as 13.2 psi on the DIC with a 3.2 pulley.

Yea, im non IC and only hear the noise at wot.

 

[b4black]

I wonder if the ported inatke has something to do with it. I assume that you cut away about half the circle below the BBV (I did). Maybe that, along with a partially open BBV makes a whistle.

Maybe try unhooking the BBV vacuum so it says fully closed and taking it for a test drive to see if the whistle changes?

 

[L36 SS]

Yea, that's what I'll probably do today to see if it goes away. Thanks