The SCCA (Sports Car Club of America) allows the use of synthetic rubber belt CVT transmissions in 3 classes: F-500, D-Sports and C-Sports. A rubber belt CVT system has been developed that can successfully transmit the 185 horsepower required to race competitively in the D-Sports class. This paper covers the development of the rubber belt CVT Transmission from a power level of 125 HP in 1986 to successfully racing with 185 HP in 1996. During the 10 year period the output level was increased by 50%. Advances in belt construction and component design to improve efficiency are described.