911 2

my 964 turbo 2 3.3 1991 seems to have a very high pitch sound when getting into the higher revs with hard acceleration is this normal or does it sound like a leak from the wastegate its definitely coming from aroud the exhaust.
the car also does not impress me after 4000 revs seems like it runs out of puff,
raced a boxter S and just managed to pull past him surley i should have left him

Kevin

Pull off your inlet boot to your turbocharger and check your compressor wheel for wheel rub on your compressor housing. If you see radial marks, you have bearing/bushing failure.. turbocharger failure.. This is the FIRST post on Rennlist (930 side) about hearing the possible bearing failure with your turbocharger.. If you have wheel rub, I take my hat off to you for hearing it, and questioning it..

Catastrophic failure is around the corner..

As your wheel is rubbing into the compressor housing, the diameter of the compressor wheel is decreasing. Friction and radial play with the reduction of the diameter is giving you the lack of boost/power..

911 2

i seem to achieve the boost 0f 0.75 bar at 3000 revs the sound is more hissing than mechanical rub its going on the rollers today

Sameer

Maybe the hissing from the turbo or you might need to check for leaks from your header gaskets?

911 2

had it on the rollers it got 1 bar at 3200 revs and holds it well so there is no leak its probably just the wastegate

Sameer

Probably is.

911 2

i think i have a little leak from the exhaust manifold but not sure whats the best way of checking as the engine sound when driving just masks all other sounds would this affect performance much

leonardtay

It won't at first... what it will do is dirty up your engine bay. Also as the leak gets worst, you would have less exhaust gas going where you want it to go... so better to nip these problems in the bud...

revolution993

Anyone figure this issue out? I changed my exhaust to fabspeed and this loud squeal comes on when accelerating.

Igooz

A picture of your new exhaust, and a better description of your issue would help. What was it before and after? Did you also change wastegate?

In the meantime, is your left exhaust pipe/wastegate side completely unmuffled/wide open now? If yes, you are probably just hearing the wastegate open under boost, and high-pressure exhaust exiting.

If that is not the case, I would remove the rubber boots to the turbo and look for rubbing of the turbine and compressor wheel in the housing.

revolution993

Thanks wastegate is stock.
i will have a look at the turbine.

revolution993

Also the car buckles at idle like it will die.🤷🏻‍♂️

fritz k.

The noise you hear is probably not coming from the exhaust system but rather boost pressure being blown off somewhere. That sounds very similar and fits with the idle disturbance that results from false air being drawn in somewhere. ​I would examine the entire pressure range after the turbo.

Another possibility is a leak in front of the turbo in the intake area. Then the sound is created by drawing in air through a small gap.

​​​​​​Fritz

911 2

I am still running the same turbo and no issues, im sure its the screamer pipe on the wastegate letting out the excess boost, boy its loud

wicks

I had a moment of this scream sound when I was limping home using the MBZ EZ unit! Which made me back way off and drive the rest of the way in granny mode. Did not scream again when running with regular EZ. Weird to see this discussed for the first time. Car has 38K miles and the wastegate was rebuilt last year which I did as preventative maintenance (I do anything with a diaphragm in it including the fuel head).

I now am getting oil dripping from my turbo pressure side. Oil may have been overfilled - not by me this time - drained some off - hoping it was that - haven't test driven again yet - but even if it was, how is oil getting out, seems to be seeping from the pressure hose (from turbo to intercooler) but the clamps are all still tight.

Side note - I get a little smoke on morning/first startup, does anyone have one of those anti-backflow valves on their 965? I have one on the 73 which does what it's supposed to.