Now NASCAR reduces size of restrictor plate

NASCAR has made a change to the restrictor plate size for Sprint Cup cars at Daytona that will sap the cars of about 2-3 miles an hour in the draft. The new restrictor plate will have holes 57/64ths of an inch in diameter, 1/64th of an inch smaller than what cars had for the Budweiser Shootout and Daytona 500 qualifying last weekend at Daytona International Speedway.

The move was made to slow the cars after Kyle Busch and Michael Waltrip posted laps of 206 mph in the Budweiser Shootout Saturday night.

NASCAR already had made a couple of changes to the engine cooling systems to limit drivers’ ability to run several consecutive laps in a two-car draft. The size of the grille opening was reduced and NASCAR is installing a valve on the radiator that will release water when it reaches a temperature of around 240 degrees – as much as 60 degrees cooler than the limit that some drivers saw during the exhibition race Saturday. Those changes are designed to make engines overheat quicker in a two-car draft.

NASCAR officials hope that by limiting the number of laps drivers can run consecutively in a two-car draft it will slow speeds.

Those changes were announced Sunday, and NASCAR officials confirmed the new plate size Wednesday morning prior to Cup practice for Thursday’s Gatorade Duel qualifying races.

Drivers still expect the two-car draft to play a role in Thursday’s races and the Daytona 500. They say that the only way to eliminate it with the carburetor restrictor plate would be to make the cars so fast that they get unstable in the corners when being pushed.

NASCAR apparently can’t afford to make the cars any faster.

“We’ve been seeing that the two-car pushing is obviously the dominating factor; [it] dominated the racing so far and it’s going to continue to do that," Hendrick Motorsports driver Jeff Gordon said. “To me, the smaller restrictor plate makes it easier to push.

“Narrowing down the opening and [installing] the pressure valve, we’re not going to be able to push as long, but we’re still going to push." Scenedaily.com