vahdyx

iTrader: (7)

So I got my stock turbo put back on and I'm curious is this noise normal. It's a very faint whistling noise. It's louder in my car, but still faint. Most passengers don't even hear it. The noise dies off when I get in higher RPMs and if I shift from 2nd to third it's not there. But if I WOT in third or fourth the noise exists. I haven't noticed it with WOTs in first or second

Cobalt SS Turbocharged Turbo Death Whine? Part 1 - YouTube

Cobalt SS Turbocharged Turbo Death? Part 2 - YouTube

Vince thinks it's normal, but he can't hear it.

My LTFT's made it to -2.3 once, but usually around -0.7 or -1.5

My boost as you can tell in the video hits the right amount and stays there, my car pulls as hard as it's always had, I can't feel a difference.

A friend of mine thinks it's normal with a GTI thinks it's normal. His GTI makes a noise too and has since he's owned it. He bought it new and it has 80k miles on it.

Thanks for your opinions.

Superbalt06

iTrader: (6)

Make a boost leak tester and test the system. That's the best way to find a leak. Spray soapy water on all places air could leak while it's pressurized. If the system holds pressure there's no leak.

SSlobalt

What kind of intake?

vahdyx

iTrader: (7)

Its in my sig, but a ZZP intake tube and ZZP's Airbox Mod

SSlobalt

You can boost leak test it to be sure, but if you can hear a boost leak, that means it's so big that you wouldn't be building that must boost. This leads me to believe it's somewhere on the intake side, or you have a fading turbo.

vahdyx

iTrader: (7)

It only happens when I get to 15psi so would that indicate a leak since the pressure is to high or can't really tell. How do I check the intake, just take off everything and check?

I also have a MPx catch can could that leak and create the whistling noise

FasterIsBetter

I have the same noise. Pretty sure its the turbo tho. I've went over boost leaks about 6 times on my car in the past month. Found two but they were making really loud noises. All I have to say is "OH WELL!" cause its getting built soon with a 6758 added to it.

vahdyx

iTrader: (7)

How long has it been doing it? And you're pretty sure its the Turbo as in dying?

FasterIsBetter

A good way to tell is pull off your intake and check for shaft play on the compressor wheel. Try to wiggle it. If it wiggles its bad.

asanti

Wait, don't all turbos have SOME shaft play? Not being a dick, just looking for info.

Later
Allex

snoftall

My car makes a similar/the same noise when under full boost. Never made it when it was stock, but then started to make it after I had GMS1 installed. I assumed it was due to the higher boost pressures. Same thing you said though, no one else seemed to notice it until I pointed it out.

SSlobalt

If it runs fine, I would just not worry about it.

FasterIsBetter

Yea, the bearings are going to have tolerances but if theres excess play he should notice it. If he wiggles it and the compressor wheel goes clonk clonk then the bearings are shot. Maybe I should have put clonk clonk in there....lol

SSlobalt

"Clonk, clonk" is a purely scentific term. True story.

vahdyx

iTrader: (7)

Haven't had time to check the "Clonk Clonk" yet, but BYT thinks since we reused the gaskets when putting back on my stock turbo (since they were only a week old), that that's what's causing the whistle.He thinks by the sound it's probably the manifold gasket.

Any opinions on this?

FasterIsBetter

Idk man. Mine does it and my turbo has never been off afaik, I can ask RossGo(original owner) if he ever had it off but I have that same exact high pitched whine.

vahdyx

iTrader: (7)

I spoke with a GM tech and he thinks a high pitched whistle is a vacuum leak. He thinks I have either a pin hole somewhere or chargepipe or intake or something isn't tight. May need to be reworked or my intake or silicone ends need to be replaced.

Depending on the chemical the shop used to clean all the oil out, there could be some deterioration.

There could be a lot of things.

Oh and I felt the shaft and it didn't wiggle. It was nice and solid...

FasterIsBetter

Yea, just go over it I guess, man. I went over my stuff a bunch of times and found nothing other than a stuck purge valve solenoid. Ordered a new one over the weekend. If I find something else I'll inform ya but unless its my intake manifold leaking where the original owner had pulled it previously to shave and paint it and reused the gasket I don't know what it is because I have went over my stuff time and time again even pulled the bumper off. Just get you a boost leak tester or build you one. I'm building one this weekend so I don't have to wait for it to come in.

RyRidesMotox

Check all of your connections first. It may be in the intake, before the turbo so don't forget to check there... negative pressure is still pressure.

Sonicyeller

My car makes the same noise even since I bought it. I'm pretty sure that's just how these K04s sound at high boost levels. Skip to about 2:25 in the video below.

Cobalt SS/TC Sedan Compilation - YouTube

And I'd think you'd agree that my car runs correctly because its right on par with where I should be at Bandimere with the mods I have.

vahdyx

iTrader: (7)

yeah I hear it, you crazy NLSer! Very nice video by the way

Sonicyeller

LOL Thanks. I've gotten much better at NLS'ing the **** out of may car since that video too. Go watch some of the videos where I race a full bolt-on and cammed LS1 Camaro on my channel if you haven't already. BTW, I wish my car held 25psi to the upper RPMs. My GMS1 hits about 23psi and then tapers off to almost 17 or so by 6000rpm.

FrossB

iTrader: (6)

not that i think that this is what it is but, my turbo made a whistle/humming noise like that when i had a messed up blade internally. you wouldn't hear anything until a little past 10psi then it would whistle like a bird.