Formula 500
From Wikipedia, the free encyclopedia
Formula 500 (F500) is a Sports Car Club of America (SCCA) open wheel road racing class.
- In Australia "Formula 500" is an unrelated sprint car class .
Formula 500 was originally introduced in the early 1980s as Formula 440 (F440). Formula 500 is a spec class in the sense that the engine, drivetrain, and shock absorbers are all tightly regulated, but the chassis, bodywork and other car parts are free for designers to experiment with within dimensional and structural limits. These regulations allow for very competitive racing at a relatively low cost which rewards driver and car set-up skill.
[edit] F500 Engines
Formula 500 cars are powered by a two cylinder, water cooled two stroke engine. Modern cars use either the Rotax 494, Rotax 493 or AMW 250-2 R2c. Older cars, mostly used for Solo events these days use the Kawasaki 440/A engine.
The Kawasaki 440/A engine , Produced by Kawasaki Heavy Industries is a 436 cc piston port engine utilizing 38 mm Mikuni VM series carburetors and a tuned dual exhaust. While this engine is no longer competitive in road racing, it is still widely used in Solo II and Autocross events. Like all F500 engines, except for the AMW, the Kawasaki was originally produced as a snowmobile engine. It has been out of production since the early 1980s. Parts for these engines are becoming more difficult to find.
The AMW 500L-85 engine, built by Two Stroke International was introduced to F500 in 1994. It is a 497 cc reed valve engine using twin 38 mm Mikuni SuperBN carburetors. To keep the performance of these larger, more powerful engines in line with prior engines, SCCA mandates the use of a spec Y exhaust manifold and single tuned pipe on the AMW engine. UNlike the other engines used in F500, the AMW engine is a derivative of a light aircraft engine. This engine is no longer in production, and is not supported by the Manufacturer.
Introduced for the 1997 season was the Rotax 494 engine. Rotax builds racing and industrial engines for a wide variety of application, including Aircraft, Motorcycles, Go-Karts, Snowmobiles and Watercraft, The 494 cc Rotax engine is a rotary valve engine. Like the AMW, the Rotax utilizes a 2 into 1 "Y" exhaust manifold and a single tuned [expansion chamber] exhaust. The Rotax engine utilizes the same 38 mm Mikuni VM carburetors as the Kawasaki. The Rotax engine has become, by far, the most popular engine in F500 road racing. Though the Rotax 494 is now out of production, Rotax continues to support it and provide parts.
In 2004 SCCA added the Rotax 493 to the list of approved engines. The 493, unlike the 494, is a reed valve engine. It also runs Mikuni VM series carbs and the "Y" exhaust manifold like its cousin the 494. Cars running the 493 engine are required to run at a higher minimum weight to maintain parity with the older 494 and AMW engines.
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 means close competition on the track.
[edit] F500 Transmission
F500 uses an advanced Continuously Variable Transmission (CVT), similar to that used in 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. Another benefit is its low cost as compared to a traditional multi-gear transmission.
[edit] External links
- The Formula 500 Racing Web is the unofficial home page of SCCA F500 racing. It is also the home of the F500 Mailing List.
- The Sports Car Club of America is the major sanctioning organization that runs F500 races in the United States.
- Formula 500 Forums at eformulacarnews.com
