NASCAR has announced that NASCAR Sprint Cup Series teams will use carburetor restrictor-plate openings of 1 1/32 inches for the July 3 event at Daytona International Speedway. The previous plate at Daytona last February was 63/64-inch.
Monday’s announcement pertains only to next month’s Coke Zero 400 Powered by Coca-Cola – the last NASCAR Sprint Cup Series event on the current Daytona asphalt. The 2.5-mile, high-banked superspeedway will be repaved prior to the 2011 Daytona 500.
Each restrictor plate contains four openings which restrict air flow to the engine, thus slowing cars. Larger openings mean more air, and more speed.
"We think this will be a needed boost due to the additional drag we've picked up since switching from a rear wing to a rear spoiler," said NASCAR Vice President of Competition Robin Pemberton.
Rule changes, announced Jan. 21, mandated switching from a wing mounted on the rear deck lid of NASCAR’s new car, back to a more traditional stock-car spoiler. The March event at Martinsville Speedway marked the first race for the new spoiler.
Carburetor restrictor plates are used only at Daytona and 2.66-mile Talladega Superspeedway. Events at those tracks are famous for their close competition.
The 1 1/32-inch size openings will be the largest since the one-inch mandate in 1988, the first year the horsepower-reducing plates were mandated for yearly use in NASCAR Sprint Cup competition at Daytona.
Teams used openings of 15/16-inch for this season’s spring race (April 25) at Talladega. That size was determined following a March 16 test at Talladega that helped answer several mechanical questions, among them, spoiler height and the restrictor-plate openings.
