Have you done a boost leak test yet? It could be posible that you have a very large boost leak and the turbo has to work way too hard to get the right pressure. Also how was the shaft play on the turbo? You also might want to double check that the coolent lines are not pinched at all.

im sorry but ususally when you hear the supercharger/ screaming cat, it means the turbo is on its way out in the near future.

yep, what he said. ^^^^^

it's possible that the wheel is hitting the housing. definately check shaft play you should have zero end play (pushing from right to left) and very little side to side play. Use a mirror and a pen light to view the compressor wheel. It should have no chips or dings in it. However it may be impossible to see if it's rubbing or not until the unit is removed and the housing is seperated. Also do you have an intake kit instead of the stock intake? this straightens airflow out and can cause the turbo to make an audible whine.

dieseltech said:

Also do you have an intake kit instead of the stock intake? this straightens airflow out and can cause the turbo to make an audible whine.

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IMO, it's more of a whistle than a whine - aka a sound pleasing to the ear, unlike the above mentioned issue. I've seen a number of posts where people say that their turbo sounds like a supercharger and it's almost always the case that the blades of the turbo are hitting the side of the housing.

could be an exhaust leak pre-turbo....like a crackin the mani

You said you finally got it running.....did you by chance have the timing belt off? Over tensioning the T-Belt will give a supercharger like whine...I know, me and my buddies car have it...it is pleasing to the ear as well. If the car boost fine and you completly rule out the turbo...check there. Or Auto tranny on its way out.

my friends starquest had the same problem, it was the turbo on its last legs...

found it. turbo outlet pipe came loose! boost leaking from broken gasket. thanks for the tips.

Napoleon Dynomite
"Luckyyy!!!"

I seem to have the same problem....

It only has happend 2-3 times in the last 3 weeks, so its not an everyday occurance. When I build boost, the turbo does make a different noise, and doesnt pull at all. My boost guage reads normal (10-11psi...the car is bone stock), so Im guessing the turbo is ok, but could it be a boost leak? I would think that if it were a boost leak that it wouldnt read anything on the boost guage. Could it be the timing belt? Help please!