Difference Between Mini & Micro Sprint Cars

Small sprint cars powered by motorcycle engines fall into either mini sprint or micro sprint classifications. The cars are very similar in design, differing primarily in their size, weight and engine displacement. Mini sprint cars are governed by the American Mini Sprint Association, and micro sprint cars are regulated by the Universal 600cc Sprint Association. The organizations publish rules that determine how cars must be configured in order to compete in sanctioned events.

  1. Mini Sprint Engines

    • AMSA rules for 2012 require that all mini sprint cars be equipped with four-cycle motorcycle engines with a maximum displacement of 1205cc and a chain final drive. Engines may be carbureted or fuel injected, and they must be fueled by either gasoline or alcohol and naturally aspirated. All cars must be capable of being self-started by the driver while he is seated in the car.

    Mini Sprint Chassis, Wings and Weight

    • Mini sprint cars must have a wheelbase between 66 and 72 inches. They must be equipped with a roll cage with a minimum of three inches head clearance for the driver inside the cage. A top wing must not exceed 16 square feet in area, and sideboards must total no more than 23.5 square feet. Nose wings are also permitted. Cars with gas-powered, 1000cc engines must weigh a minimum of 900 pounds including the driver, and 1000cc alcohol-fueled cars must weigh at least 940 pounds. Cars with engines between 1000cc and 1205cc must weigh a minimum of 1,040 pounds.

    Micro Sprint Engines

    • The 2011 U6SA rules specify that micro sprint cars must be powered by a four-stroke, four-cylinder production motorcycle engine with a chain drive. The displacement of an engine manufactured in 2006 or later must be no more than 600cc; engines manufactured before 2006 must have a displacement of no more than 637cc. Engines must be self-starting and must be fueled by either gasoline or alcohol. Fuel injection is only allowed if the engine was originally equipped with it by the manufacturer.

    Micro Sprint Chassis, Wings and Weight

    • Micros with a top wing must have a rectangular, one-piece center air foil no larger than 12 square feet in area, and the wing cannot extend past the car's rear tires on the sides or behind the rear bumper in back. If the car has a nose wing, it must be no larger than 4 square feet, and it also cannot extend past the outer edge of the wheels or further forward than the front bumper. The minimum total weight for car and driver is 775 pounds for a winged car and 750 pounds for a wingless car.