Turbochargers are centrifugal compressorsdriven by an exhaust gas turbine and employed in engines to boost the chargeair pressure. Turbocharger performance influences all important engineparameters, such as fuel economy, power, and emissions.

The turbine-compressor common shaft issupported by a bearing system in the center housing located between thecompressor and turbine. The shaft wheel assembly (SWA) refers to the shaft withthe compressor and turbine wheels attached, i.e., the rotating assembly.