Abstract: A turbocharger having a centrifugal compressor includes a vaned diffuser. The vaned diffuser is formed by a diffuser ring formed separately from the compressor housing and center housing. The diffuser ring is installed between the compressor and center housings such that a diffuser passage is defined between a surface of the compressor housing and a surface of the diffuser ring. Integral vanes on the diffuser ring extend only partially across the axial width of the diffuser passage. A rectangular-section seal ring is axially compressed between the compressor housing and the diffuser ring for sealing and axial locating of the diffuser ring. Radial locating of the diffuser ring is accomplished by an integral locating pin on the ring, which fits into a receptacle in the center housing.