

Formula 500 is a Sports Car Club of America’s (SCCA) lightweight open wheel road racing class. Formula 500 was originally introduced in the late 1960s. Formula 500 is a spec. class, which means that modifications to the engine, drive train and suspensions are tightly regulated. This provides for very competitive road racing at a reasonable cost.
Formula 500 cars are powered by a two cylinder, water cooled, two stroke Rotax engine. The Rotax engine was introduced to Formula 500 in 1997, and has become, by far, the most popular engine in Formula 500 road racing. Rotax builds racing and industrial engines for a wide variety of applications, including aircraft, watercraft, motorcycles, and snowmobiles. The Rotax 494cc engine is a rotary valve engine which utilizes a 2 into 1 "Y" exhaust manifold and single tuned expansion chamber exhaust.
SCCA is currently evaluating two new Rotax engine models for Formula 500: the RAVE valve version of the Rotax 494 and a new Rotax 493 reed valve engine. The 493 engine is currently subject to a 50lb weight penalty if used.
Engine specifications are tightly regulated by the SCCA. No engine modifications are permitted in Formula 500. Engines must be run in stock form "as delivered" from the factory. No aftermarket parts, port modifications, or other variations from stock configuration are allowed. This helps keep costs down and competition close on the track while promoting and encouraging the development of driver talent.
Formula 500 racecars use an advanced Continuously Variable Transmission (CVT), the same used in racing snowmobiles. These advanced belt driven automatic transmissions are tuned to optimize the power curve of a two stroke engine, constantly keeping the engine at its peak power. One of the key benefits of the CVT is that it is a stepless transmission. This allows all of the engine's power to be transmitted to the drive wheels at all times.
Top speed for a modern Formula 500 racecar is about 130 MPH on a road course. Lap times at most tracks are within 1 or 2 seconds of a top Formula Ford. Weight limits are strictly enforced to a minimum of 800 pounds, which includes the driver.
The United States Military’s new Predator UAV (Unmanned Aerial Vehicle), used in some military applications, uses the same engine manufacturer as Formula 500 racecars.