Racing fuel can refer to many different common fuels used in motorsports: Leaded gasoline, formerly used by the NASCAR series and other motorsports Use of leaded gasoline in NASCAR Nitromethane and methanol fuel, used by Top Fuel drag racing Methanol fuel, formerly used in some open-wheel race cars, like IndyCar Series prior to 2007 and in Top Alcohol drag racing Ethanol fuel, now being used in the IndyCar Series and NASCAR Nitrous, used by drag racing vehicles to increase horsepower