although you've touched on it there Chip, maybe more detail on what a turbo actually is

basically two Turbine wheels ( like propellers ) mounted on the end of a single shaft , at one end is the exhaust turbine (hot side), the other end is a compressor turbine (cold side )

on this picture ( with the compressor and exhaust housings removed), the larger wheel is the compressor and at the other end is the exhaust , the section between is known as the core, this contains the bearings, seals and galleries for the oil and water to run ( seperately of course ) . the shaft needs to spin dead centrally,if it didn't then it would probably result in a noisy whining turbo or worse, a broken turbo! the water and oil galleries are for lubrication and cooling.



this is a similar picture with the housings attached.