Design and Development of an 850 cc Single Crankshaft V-4 Two-Stroke Engine for SCCA D-Sports Racing

The SCCA (Sports Car Club of America) D-Sports class allows 2 stroke engines of up to 850 cc and a maximum of 4 cylinders. An 850 cc single crankshaft V-4 two stroke engine has been designed, developed and successfully raced in the SCCA D-Sports class. This paper covers the design philosophy and development history from prototype engine to a reliable power unit that can win major SCCA national races and compete a full season without failure. Piston and cylinder design, crankshaft development and design of intake and exhaust systems that produce acceptable component life and competitive power output is described.