Abstract: A controlled area progression diffuser for a compressor may be defined by a bearing diffuser face of a bearing housing and a compressor diffuser face of a compressor housing that are spaced apart by a diffuser width, and airflow from a compressor wheel enters the controlled area progression diffuser through a diffuser inlet, flows between the diffuser faces, and flows out of a diffuser outlet to a volute. The diffuser faces may be shaped so that the diffuser width decreases as the controlled area progression diffuser extends radially away from the compressor wheel toward the volute so that an annulus area of the controlled area progression diffuser does not increase linearly for at least a portion of a radial length of the controlled area progression diffuser.

Abstract: A turbocharger is disclosed. The turbocharger may comprise a turbine, and a compressor having a radial impeller. The radial impeller may include a body having a hub and a plurality of main blades extending from the hub. Each of the main blades may have a leading edge. The turbocharger may further comprise a plurality of serrations extending along the leading edge of each of the main blades, and a shaft interconnecting the compressor and the turbine. The body of the impeller may be formed by flank milling, and the serrations extending along the leading edges of the main blades may be formed by point milling.