Mighty Shilling

and I know some people say it's normal, but honestly it really concerns me. what sort of thing can I check? I'm running normal boost and vacuum, so I don't think I have any leaks in the system, so where else to check? I saw the pic of the guy's turbo with nut that fell off and shaved the turbine down, and he said that was why it's whistling, and someone else had play in their turbo shaft, and seeing those threads has made me paranoid as hell...

what can I check so my mind will be at ease?

NZ951

Some noise is certainly normal, ESPECIALLY with a pod filter type assembly. If you are hearing excessive noise, and suspect the noise is the compressor blades scratching the compressor cover, then check for shaft play and see if there is any visible scratching between the blades on the cover.

Mighty Shilling

roger. I have my weekend project...

Porschefile

Do you have any mods done or is the car basically stock? A modified intake (not the manifold) will usually cause a noticeable amount more turbo "whistle", which is completely normal. If the car is completely stock, and if it's more of a whine then your turbo could possibly be on it's way out. Take the intake off and try to wiggle the compressor wheel around. If it moves around quite a bit or if there is visible signs of damage (chipped wheels, erosion of the blade tips, etc) then you've probably found your problem.

billthe3

How exactly do you measure play in the shaft? I've got my stock one pulled out and can't feel any play in the unit with my fingers, but would like to use some sort of actual method to measure to see if there is any.

hosrom_951

You need a dial indicator as well as a stand/support for it since they are extremly sensitive.

NZ951

Bill,

I am sure there is a Porsche tolerance for the play in the shaft. You are talking thousandeths of an inch, the best way to check if its out of tolerance is looking for scoring on the cover.

FYI play in the shaft is caused by bearing wear in the centre section of the turbo. The LAST thing you want is a compressor wheel go through your motor and score those lovely bores and sodium filed valves! HOWEVER, there is always some play in the shaft, you should be able to still feel it with fingers, if you cant, it must have either seized or you have a very tight wee unit!

billthe3

Cool, thanks for the info. For as much as I know, its still the stock 26/6 with 85k mi on it. Aside from the car having the bad compression numbers on the one cylinder causing my current teardown, everything else seems to be in pretty good condition. The turbo worked perfectly before I pulled it, so I know it wasn't siezed (lol), but I'll go see if I can feel any movement again tomorrow/today and if there is any scoring on the housing.

xsboost90

i can hear mine spool- with the windows down- thats why i own a turbo!

ausgeflippt951

^^I can't...because I'm only getting 1.2 bar!!! grrrrr........

xsboost90

must be a factory gauge then!

i can hear mine at 13psi.

jakery

Mine sounds like a 747 during takeoff, and the blowoff sounds like a trucks airbrakes releasing, but then again the only thing Eyal left stock on my car is the carpet & i love it that way.

ibkevin

One of my favs... not!

ausgeflippt951

^^ that's still in spec, right? you're only reading a little under 70/1000s correct?

Mighty Shilling

if the compressor wheel were rubbing against the housing, wouldn't I see sparkly bits on the inside of my intercooler pipes? just looking for something else to look for...