A turbocharger (5) comprising a housing (10) including a compressor shroud (14) and a turbine shroud (12). A compressor wheel (18) is disposed in the compressor shroud (14) and includes a plurality of compressor blades (45, 46). Each compressor blade (45, 46) includes a leading edge (50, 51) and a compressor shroud contour edge (54, 55), wherein each compressor shroud contour edge (54, 55) is in close confronting relation to the compressor shroud (14). A turbine wheel (16) is disposed in the turbine shroud (12) and includes a plurality of turbine blades (26). Each turbine blade (26) includes a leading edge (30) and a turbine shroud contour edge (34), wherein each turbine shroud contour edge (34) is in close confronting relation to the turbine shroud (12). At least one of the compressor shroud (14) and turbine shroud (12) includes a plurality of grooves (70, 72) extending cross-wise with respect to the corresponding compressor or turbine shroud contour edges (34, 54, 55).