S5 turbo turbine... how much damage is too much damage?
 

I bought what was supposed to be a rebuilt turbo a while back. Time is limited, so unfortunately it takes a while to install parts and what not. Well, after initial start up, the turbo smoked around the turbine housing. It just continued to get worse and worse. I pulled the turbo, and immediately noticed where oil was leaking from the turbine side and running down and cooking onto the turbo. I disassembled the turbo and oil had built carbon up around the heat shield and on the turbine wheel itself. This would explain why the car would start smoking something awful. There is also some slight scoring on the shaft where the journal bearings go. The bearing closest to the turbine is visibly shot. The shaft itself is discolored, almost like a blueish purple color, I would think maybe from excessive heat buildup. I just don't know if I should reuse this turbine shaft or not. Unfortunately, the spare turbos I have, 2 of them are completely shot, and the 3rd might be usable. It isn't completely ate up like the other 2, it has very small nicks out of the outer edge of the turbine wheel. I will attempt to post pics of the 2 wheels I currently have and get an opinion.

The rest of the turbo is ok. It's a hybrid turbo that uses a knightsport compressor and the waste gate has been significantly ported. From the measurement, it appears to be a u-trim compressor wheel (70mm x 54mm) rounded up.

Anyhow, all in all, I wish I would've ordered a BNR turbo from the get go. At the time, like most, I was trying to save a few bucks. I'd like to try and salvage this turbo, so if I need a new (used) turbine wheel, if someone has one, shoot me a price. I don't really want to trash the whole turbo. I have a rebuild kit and even the 360 degree thrust washer upgrade. Any help or advice/guidance is greatly appreciated. I already have the awesome turbo rebuild thread book marked. Thank in advance!

This is the clipped wheel that came from the smoking turbo. I do not understand why they ground the nut off the end of the turbine. This make getting the compressor nut off a royal pain ... i used rags wrapped around the turbine and a vise... being careful to not bend fins.

This is the other stock turbine that i have. The damage is minimal. .. i just want an opinion. No damage is probably ideal.

i think with the stock one, it could be useable, it would be nice to clean it up a little though.

if it was mine, i'd try to clean up the clipped one though. the shaft is a little blue, but its not scored

Definitely going to clean everything up before I reassemble it. I've read a few articles on clipping and why it's done etc... more top end flow and helps with boost creep. Most say it creates more turbo lag but with the clipping and since the nut is shaved off (still don't understand this one) it creates less rotating mass which can speed up spool times... any thoughts? Any other thoughts on these wheels.. use them or start over?

yeah lighter = faster spool. clipping should reduce the turbine efficiency, but since the engine likes to breath more than the turbine needs efficiency...