NASCAR RESTRICTOR PLATE SMALLER FOR DAYTONA

When Sprint Cup drivers test at Daytona International Speedway next week, they will do so with a restrictor plate with slightly smaller holes than what was used during last month’s tire test on the newly repaved track.

NASCAR has reduced the size of the holes in the restrictor plate by 1/32nd of an inch – from 30/32nds of an inch to 29/32nds of an inch – a NASCAR spokesman confirmed Wednesday night.
During the Goodyear test last month, drivers reached speeds of 197 mph in the draft. If the cars react the same to similar changes made in the past, the smaller restrictor plate would cause a drop of about 20 horsepower and result in a drop in speeds of approximately 5-10 mph on a qualifying lap and a 3-5 mph drop in the draft.
A restrictor plate limits the airflow that runs through the engine and therefore saps engine of horsepower. Typically, the restricted Cup engines produce between 450-500 horsepower.
Drivers participating in the test didn’t seem too concerned about the high speeds, but in announcing the change, it appears NASCAR officials are concerned that the cars could go too fast for their comfort – especially if the teams make gains, as is expected, in their setups from the December test to the Jan. 20-22 test.
During the December test, NASCAR Vice President of Competition Robin Pemberton indicated a restrictor-plate change could be forthcoming.
“We’ll have to get back and talk to the teams and look at the speeds from the last two days of testing,” Pemberton said. “I think we have some high-water marks at 197-and-a-half, which depending on where they pulled up in the draft, it may be a little quick, but it’s hard to say.”
Only 18 teams participated in the December test, while more than 40 drivers are expected for the Jan. 20-22 test on the new pavement. It will be the first time in three years that all Cup teams are getting to test at Daytona. The test is being done because the 2.5-mile surface was repaved following the track’s Independence Day race. At that race, the restrictor plates had holes 33/32nds of an inch, while at Talladega, the only other track where the plates are used, the holes were 30/32nds (15/16ths).
NASCAR will keep the spoiler angle at 70 degrees and the dimensions of the spoiler, 4.5 inches tall and 63 inches long, will also remain the same.