Four diesel-powered passenger cars were subjected to a wide variety of emission and economy evaluations, and the results are presented in this paper. The four production cars included a 1972 Mercedes-Benz 220D, a 1973 Peugeot 504D, an Opel Rekord 2100D, and a Nissan diesel-powered Datsun. Tailpipe emissions were measured by the 1975 Light Duty Federal Test Procedure for gaseous emissions, fuel economy (carbon balance and gravimetric) and smoke. Smoke and gaseous emissions were also measured by chassis dynamometer versions of the 1974 Federal heavy-duty procedures. Odor and related instrumental-chemical measurements were made under seven steady-state and three transient conditions. Odor was measured by a trained panel and the analytical system developed by A. D. Little, Inc., under CRC contract. Noise measurements were taken during SAE driveby and a variety of of interior-exterior conditions. The results are compared by category to each other, Federal limits, and to test results obtained by EPA laboratories.