Systematic and computerized mapping procedures were developed to characterize the performance of an engine as a function of speed, load, ignition timing, air-fuel ratio, and percent of exhaust gas recirculation. Using these techniques a map of a carbureted, 5.7 ℓ, spark ignited V-8 engine has been obtained. This five parameter map data base resides in a large computer system which allows access by multiple users. The mapping procedures combine a rational approach to the selection of speed-load points for engine mapping with a computerized test incorporating a slow sweep of the independent variables with simultaneous data acquisition. The result is more accurate engine characterization data with less effort and in less time than is possible with conventional procedures. The high data density of this map enabled the development of valid models for fuel and emissions by curve fitting techniques.