Sliding piston cartridge and turbocharger incorporating same

A sliding piston cartridge for a turbocharger that is insertable into a bore in the turbine housing as a unit and that includes all of the components of a sliding piston type variable nozzle. The sliding piston cartridge comprises a carrier having a tubular portion that interfaces with the bore of the turbine housing. A sliding piston is disposed within the carrier and makes sliding contact therewith. Vanes are mounted on or formed as a part of the carrier at its upstream end, the vanes extending across a turbine nozzle. The piston slides between a closed position and an open position relative to the carrier. The tubular portion of the carrier can include openings that are progressively uncovered by the piston as it moves toward the open position, to allow additional flow to enter the turbine wheel without passing through the vanes.