Air leak sound at high RPM

[TheMyth]

Ok so here is what i have, I have what sounds like a air/vaccum leak sound from the engine area when I am around 2800 RPM and about 75% into the throttle. I checked the couplers for the the pipes on the turbo and those seem to be fine (only exception is the drivers side coupler slips a little when tightening it but i got it to hold). I'm not sure if anyone else has had this issue, but i am hoping it isnt bearings going out on the turbo, i checked the turbo about 1500 miles ago when i changed out the FPR. Hoping someone has some suggestions.

I dont have guages so I cant see if i am losing boost when it happens.

 

[yellowchevy]

Do you have a way to pressure test your cold & hot side?
How much is that clamp holding? They need to be pretty strong otherwise they will leak.
Are you getting any black smoke when at 3/4 throttle?

If you can take the plastic intake off the turbo, hook up a cap with a gauge so you can pressuize the system to 10 - 15 psi. Then take some soaping water and put on your connects, if you have a leak you'll see bubbles. If you don't see any leaks on your connections I would move onto your intercooler.

Yellowchevy

 

[TheMyth]

The clamps appear like it is holding fine, was thinking bout oredering a new coupler kit. I dont have black smoke but i do have some grey/white smoke but it has done that since i have had the truck. It was tuned right after i bought it and it isnt heavy smoke, just enough to see it when i really get on it.

 

[RickDLance]

Check for exhaust leaks too. The gasket design gm uses can whistle.

 

[TheMyth]

So here is what i looked at and then what i did. The coupler on the hot side turbo pipe was thrashed, kept slipping and it finally shot off yesterday morning on the way to work yay!!!!!

Saturday I said screw it and ordered a Banks Power tube, it came in yesterday and I replaced the coupler and tube. Runs better, still a slight almost whine at this point when i really get on it.

 

[chevyburnout1]

If it's still making the noise check for exhaust leaks at the #7 exhaust port. Seems to be a common leak area on the early LLY's

 

[TheMyth]

Is it usually a loose exhaust bolt or something more costly?

 

[chevyburnout1]

The bolts seem snug on the ones I've done. So far just replacing the gasket fixes it just fine.

 

[catman3126]

do you have an egr blocker plate installed? if so check it, they can leak and make a high pitched screech sound.

 

[TheMyth]

Yea i do have one on there and i have checked that, it is a differnt sound than what is normally associated with that. (had that leak before)

Thanks for the ideas so far

 

[gmpat21]

I just experienced the exact same thing on a truck. Check the gasket between the intake and ybridge mouthpiece the oval gasket with two bolt holes. I had a folded gasket causing noise

 

[gmpat21]

Take your map sensor out and smoke test system

 

[Trotorx2]

The elbow on my S&B intake deformed on the bottom that caused an opening that drew air in. It made that kind of sound at high throttle settings.