NASCAR announced today a timeline to phase unleaded fuel into its three national series beginning next month. The unleaded fuel will first be used for the NASCAR Busch Series race at Gateway International Raceway on July 29.  The plan is to evaluate the use of unleaded fuel over several NASCAR Busch Series and NASCAR Craftsman Truck Series events this season before making a decision on when it will be mandated for all three national series.

Unleaded fuel will be used for four weeks before undergoing an evaluation period. After the race weekend at Gateway, the fuel will be used at O'Reilly Raceway Park at Indianapolis on Aug. 4 and 5 for the NASCAR Busch Series and NASCAR Craftsman Truck Series; at Watkins Glen for the NASCAR Busch Series and Nashville Superspeedway for the NASCAR Craftsman Truck Series on Aug. 12; and at Michigan International Speedway for the NASCAR Busch Series on Aug. 19.

Following those events, competitors will return to their regular fuel for four weeks while NASCAR, Sunoco and team engine builders evaluate the effects of the new fuel. On Sept. 23 the NASCAR Busch Series (Dover International Speedway) and NASCAR Craftsman Truck Series (Las Vegas Motor Speedway) will resume using unleaded fuel for the remainder of the season.

In addition, NASCAR, Sunoco and NASCAR NEXTEL Cup Series engine builders plan to work with the ARCA Re/Max Series at Talladega Superspeedway to study the use of unleaded fuel in engines with restrictor plates.

Following the season, a decision will be made on the future of unleaded fuel. NASCAR had previously announced a switch to unleaded fuel by 2008. The current goal is to have all three national series using unleaded fuel fulltime by Speedweeks of 2007.