R33 Gtst - Turbo Noise

[GeeDog]

Our R33 has developed a noise coming from the turbo area. I'm pretty sure I know the answer (turbo stuffed) and the fix, but wanted to make sure there isn't another reason for it before pulling it all apart.

The turbo is stock as far as we know, and the rest of the engine is stock other than a 3" cat-back and an R34 SMIC. The noise is similar to the screaching sound when a drive belt slips, and is there whenever the turbo is boosting. It seems to boost as normal, and power is fine. The noise started during a supersprint event (think track day with official timing) on Sunday, but wasn't really obvious with a helmet on, and suspected a small boost leak. Driving home with helmet off it was clearly not normal.

Anyone have ideas other than the turbo itself?

[Ben C34]

As you mentioned it could be a boost leak.

Pressure test to check before removing turbo.

[scotty nm35]

Exhaust manifold gasket could be stuffed, or the T3 flange warped. They can squeal like a stuck pig on boost when the manifold pressure rises...

Try the boost leaks first, and check for shaft play on the turbo while you are there.

[ANT_32]

I had this problem.

It was the gasket between the turbo and the exhaust manifold.

[Blackkers]

if the noise is THAT bad and its still performing as normal then perhaps the turbo is okay

[GeeDog]

Thanks for the replies - have already done a boost leak check & fixed a very small leak from the plug where the carbon cannister used to be connected, other than that there isn't any other leaks.

Will check the gaskets today or tomorrow. How hard is it to get to this area, what needs to be removed, and shortcuts?

Scotty - T3 flange warped - is it likely to be warped on the manifold or the turbo?

[GeeDog]

if the noise is THAT bad and its still performing as normal then perhaps the turbo is okay

Power is fine - the last few laps on Sunday were the fastest, by over a second per lap. The noise had been there most of the day, but was getting louder as the day went on. It didn't sound so bad with a helmet on.

[scotty nm35]

The T3 gasket could have gone, but usually the turbo flange warps from massive heat and pressure due to track work. Not sure if the weight of the exhaust hanging off it makes it worse... I have seen it a few times on tracked cars running smaller turbo housings.

Either way you will need to check both ends of the turbo to know if it's ok or not.

[GeeDog]

Managed to get into it yesterday - the turbo was loose on the manifold. One nut was missing, and the other 3 were loose - even with the retaining clips in place.

Good news is that there is negligible play in the turbo.

[Blackkers]

sick

[GeeDog]

Just to add some closure - replaced gaskets & dump bolts & everything is sweet. Not sure how long it had been leaking but it got worse during the event on Sunday. Runs beautifully now.

Thanks for the help.

[scotty nm35]

Great to hear Geoff.

I just found a Permaseal MLS-R gasket at Bursons, they are the same as OEM and cheap at $18 shelf price.