Squeak coming off turbo?

[cctman]

Anyone have any ideas what this could be? It only happens when I come off gas around max torque. It does it in usually upper gears from pulling from low RPM to 3/4. [video]https://youtu.be/3_pyX-BH9dc[/video]

Hard to here in this clip but sometimes it gets really loud off a light. Around 2 sec mark.

 

[STephen]

You're not alone. I'm interested to hear what people say

 

[MMMTRBO]

Yup I get it too. High gear, high boost and lower RPMs.

 

[cctman]

ITs gotten worse over last couple years. It didn't seem to do it until I added an AP and started using higher stage maps. If I lower the stage map, it seems to either get feint enough I can't hear it or it completely goes away. But I think the correlation here is with higher torque and quick let off boost in higher gears when engine is under most load.

Those of you that are hearing this are you using an intake? What kind? And an AP? What stage map?

 

[johnlopez624]

mine does that but its 100x louder cause of my 2j intake. ima go get my camera and see if i can cut a clip out from when i drive around. mine actually screeches pretty loud. im sure people out the car can hear it. I never heard it before i got my 2j intake.and the boomba bov + 2j intake = screeches/chirps all the time.

 

[STephen]

ITs gotten worse over last couple years. It didn't seem to do it until I added an AP and started using higher stage maps. If I lower the stage map, it seems to either get feint enough I can't hear it or it completely goes away. But I think the correlation here is with higher torque and quick let off boost in higher gears when engine is under most load.

Hose of you that are hearing this are you using an intake? What kind? And an AP? What stage map?

Mine began once I started OTS stage 1 with the AP. So I'm only using the AP and a drop-in air filter.

 

[MMMTRBO]

I started hearing it after going Stage 3, all COBB parts.

 

[Hijinx]

OP, what mods do you have?

 

[redsilvy]

Mine does the same.. Heard it after going stage 1 with an injen intake.

 

[cctman]

OP, what mods do you have?

Cobb AP(now stage 3),
injen intake(could this be the issue or combo with AP?),
levels IC,
2JR non-catted DP,
2JR race exhaust.

Sounds terrible. I think maybe we need to get someone with good deal of race experience, Cobb, or Injen guy commenting on this.

 

[RStolz]

I've noticed it on mine, all stock. Just assumed it was a byproduct of the wastegate or DV opening. a lot of air trying to escape a tiny opening...

 

[Hijinx]

Listening with headphones... It definitely should not be a squeak.

I repeat a squeak is not normal.

The Darth Vader exhale is.

It's hard to diagnose from a video and not in person but I would say you're getting some "bark." The turbo is stalling/reversing when you let off the gas.

Good news is you can avoid it by not letting off the gas abruptly in that low rpm/high load situation.

 

[cctman]

Listening with headphones... It definitely should not be a squeak.

I repeat a squeak is not normal.

The Darth Vader exhale is.

It's hard to diagnose from a video and not in person but I would say you're getting some "bark." The turbo is stalling/reversing when you let off the gas.

Good news is you can avoid it by not letting off the gas abruptly in that low rpm/high load situation.

Not sure I can. Mine when under load meaning normal acceleration does it all the time. Even when a low rpm pull from 3'rd or 4th gear and then shifting to 5th it squeaks. Its not like I'm drag racing or anything. First thing is to make sure I'm not dealing with something broke, second how do I fix it because its annoying and can be heard loudly outside the car at times.

 

[Hijinx]

You brought it used?

 

[RStolz]

The turbo is stalling/reversing when you let off the gas.
.

respectfully, the turbo reversing is basically impossible. It would require negative pressure through the entire exhaust stream (air getting sucked INTO the exhaust) as well as air being pushed out the intake side. Which would be extremely bad... for everyone. no other way for the turbo to reverse its momentum.

If it's stalling, then the bearing and center section (CHRA) of the turbo is shot, and there's nothing to be done except replace it.

I'd look a lot closer at the diaphragm in the stock diverter valve being potentially compromised.

 

[Hijinx]

respectfully, the turbo reversing is basically impossible. It would require negative pressure through the entire exhaust stream (air getting sucked INTO the exhaust) as well as air being pushed out the intake side. Which would be extremely bad... for everyone. no other way for the turbo to reverse its momentum.

If it's stalling, then the bearing and center section (CHRA) of the turbo is shot, and there's nothing to be done except replace it.

I'd look a lot closer at the diaphragm in the stock diverter valve being potentially compromised.

No worries. It is entirely possible for a turbo to stall and push air out through the intake tract. Also, there is negative pressure entering the exhaust stream. The reason you hear those little pops and burbles is the result of the positive and negative air pressures colliding in the exhaust stream.

 

[RStolz]

No worries. It is entirely possible for a turbo to stall and push air out through the intake tract. Also, there is negative pressure entering the exhaust stream. The reason you hear those little pops and burbles is the result of the positive and negative air pressures colliding in the exhaust stream.

After a fair amount of research, I think I follow what you mean. The way you guys talk about these things is remarkably different than the german crowd... still getting used to that.

you're basically talking about a turbo surge, right? Manifold pressure spiking high enough to cause enough reverse pressure to airbrake the turbo.

I think I'd still suspect the DV first, if only because that'll be the cheapest failure point, and the device directly responsible for preventing surge, followed by the wastegate.

 

[Hijinx]

After a fair amount of research, I think I follow what you mean. The way you guys talk about these things is remarkably different than the german crowd... still getting used to that.

you're basically talking about a turbo surge, right? Manifold pressure spiking high enough to cause enough reverse pressure to airbrake the turbo.

I think I'd still suspect the DV first, if only because that'll be the cheapest failure point, and the device directly responsible for preventing surge, followed by the wastegate.

To be fair, I'm American. That means you've probably got the right terminology lol. I don't think the turbo will actually stop spinning or reverse direction. We (or at least myself) will use terms for effect because, generally, we're immersed in addressing the lowest common denominator.

Anyway, I agree with you on the diverter valve. In OPs case, the air isn't leaving the pipes fast enough causing the stall/surge. Before we go replacing parts, though, he should ensure all of his clamps are tightened. Then DV, then wastegate, then check for shaft play.

 

[RStolz]

I meant the german car crowd, not literal germans. My garage toy is a Mk1 VW rabbit with 1.8T swap.

we're on the same page.

 

[FearTheSnail]

Sounds like the stock bypass valve to me. Add a boomba spacer and you will hear it even more.