Does replacing the compressor wheel of a turbo require that the entire assembly be rebalanced?
I believe these things are balanced assembled with both turbines on them, but I'm not sure...

 

Some people say you don't have to, but rotating assemblys are balanced to less than .25 gram combined.

 

Some say it depends on the company of the turbo. For example, some Garrett turbo's have the shaft and exhaust wheel balanced seperately from the compressor wheel, while others are balanced as a whole assembly. If you ask any serious rebuild shop, they will usually tell you it's best to balance as a complete assembly though, and honestly that's probably the best insurance.

 

Its best to have it balanced. The best way is to have the compressor and turbine wheels balanced separately then rebalanced together in the rotating assembly. This is the most expensive option however.