An advanced turbocharger has been developed through the prototype stage which has demonstrated performance in actual engine installations. The design addresses many of the problem areas associated with contemporary turbo-chargers. The design features include variable area turbine nozzles, self-contained lubrication, and a rotor shaft supported by ball bearings. Several operational experiences are discussed which illustrate improved transient response and improved diesel engine specific fuel consumption. The operational experience includes diesel and spark ignition. Vertical shaft installations are also included.