Turbo Rebuild Troubleshooting

[SHOuldnt_be_here]

Mornin all, just finished up a rebuild on the front turbo, it didnt blow or anything, just wanted to get to it before something happened. Nothing changed just a new CHRA core and oil lines and such.

Everything meticulously cleaned and installed to spec and properly torqued. No codes, no leaks, proper boost as far as everything reads(as far as i can tell from what my scanner will tell me)....but this damn turbo sounds like a weedwacker when spooling up! I thought maybe a stuck wastegate but nope, I've checked all my lines and the wastegates and, everything seems to be perfectly fine.

Am i stupid? Am i just crazy? Please let me know if it's staring me in the face but I can't for the life of me figure out what it is.

Thank you all and have a wonderful day.

 

[BradM]

Exhaust leak? Did you re-use your old gaskets?

 

[SHOuldnt_be_here]

Exhaust leak? Did you re-use your old gaskets?

Not that I can tell as of yet, used all new gaskets and it sounds enormously different than the other exhaust leaks I've had. Literally like a weedwacker string flying through the air. I've looked all over the web for the same/similar issue and no dice.

 

[BradM]

Did the turbo spin freely after the rebuild? Maybe something is rubbing. Try spinning it by hand to make sure.

 

[SHOuldnt_be_here]

Did the turbo spin freely after the rebuild? Maybe something is rubbing. Try spinning it by hand to make sure.

Checked all the clearances before install, everything spun freely no rubbing. Installed it and primed it, still spun freely with no issues. Gonna put her back up today after work and see if i can't track it down.

Could it be the actuator for the wastegate? The vacuum line from the actuator to the boost solenoid is good but could it be something inside the actuator head?

 

[BradM]

In theory the diaphragm in the WG actuator could be leaking and make a weird sound but I'm thinking of things related to the rebuild. You could manually apply vacuum to the WG and see if it leaks down.

 

[SHOuldnt_be_here]

In theory the diaphragm in the WG actuator could be leaking and make a weird sound but I'm thinking of things related to the rebuild. You could manually apply vacuum to the WG and see if it leaks down.

Yeah that'll be the first thing I do.

I was initially concerned I did something wrong when rebuilding as well, which is entirely possible as with anything...but, I followed all install procedures and followed the torque sheet, made sure everything was clean, did everything i could to be perfect. The reassembly was honestly quite straightforward and everything went in okay, or so I thought.

 

[SHOdded]

have you compared oem and rebuild turbos? the vanes are visible but the bearings are not. multiple possible differences can contribute to the change in sound. lot of money spent on acoustic engineering.

not all chra kits are equal in build quality of course.

 

[BradM]

What core did you use and did you install the o-ring?

 

[SHOuldnt_be_here]

What core did you use and did you install the o-ring?

Using rotomaster replacement cores, so far only done the front turbo and i definitelyinstalled the new o ring.

have you compared oem and rebuild turbos? the vanes are visible but the bearings are not. multiple possible differences can contribute to the change in sound. lot of money spent on acoustic engineering.

not all chra kits are equal in build quality of course.

On the outside the cores are identical.

As a note and a bit of an update: I can definitely tell I'm underboost right now, though I have no underboost codes....and my fuel economy has dropped quite a bit. Which seems to tell me I'm leaking boost somewhere, right?