The operating point where the compressor speed lines, and the engine’s operating line meet is critical. Thus, improvement of the efficiency at that point is of paramount importance. Through systematic development of the single-stage supercharger by (i) incremental improvements to the compressor impeller, (ii) the arrangement and development of the diffuser vanes, and (iii) the shape of the outer volute/spiral, significant gains in the performance of the single-stage compressor have been made.