The test procedures outlined in this recommended practice are applicable to single rotor turbochargers having either fixed- or variable-geometry with the following caveat: At this stage in the development of variable-geometry (VG) turbochargers, it would be impractical to generate a detailed practice to cover all types of VG turbochargers which may evolve. However, there is a requirement to quote performance data within a stipulated degree of accuracy and to furnish comprehensive performance information. This will form a basis for this document where further refinements may be added as experience and necessity dictate.