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NASCAR Unveils 2021 NASCAR Cup Series Rules Package Specifications; Darlington Using 750-Horsepower Package

DARLINGTON, SOUTH CAROLINA – SEPTEMBER 06: Chase Elliott, driver of the #9 NAPA Auto Parts Throwback Chevrolet, and Denny Hamlin, driver of the #11 Federal Express Toyota, lead the field to start the NASCAR Cup Series Cook Out Southern 500 at Darlington Raceway on September 06, 2020 in Darlington, South Carolina. (Photo by Chris Keane/Getty Images)

On Thursday Afternoon, NASCAR delivered the 2021 Cup Series rules package to teams, highlighted by changes in the aerodynamic package for the series’ two dates at Darlington Raceway on May 9th and September 5th.

In these two events, – which used the 550-horsepower package in its three events in 2020 — NASCAR Cup Series teams will be running the 750-horsepower, low-downforce package that was run at tracks one mile in length and under, as well as at road courses.

In addition to more horsepower, that package includes:

  • A significantly smaller rear spoiler, which will be shrunk ~290% – from an 8-inch height to 2.75 inches in height.
  • The front splitter’s overhang measures a quarter-inch (down from two inches), with approximately two-inch wings (reduced from 10.5 inches)
  • Alterations to the radiator pan, removing its vertical fencing in an effort to reduce front-end downforce. The dimensions of the pan will remain the same.

The 750-horsepower package will be used in a total of 23 events in 2021, including the series’ first ever event at Nashville Superspeedway.

“We constantly review the race packages to try to put on the best possible racing for our fans,” said John Probst, NASCAR’s senior vice president, innovation and racing development. “When we brought in the short track/road course package this season, Darlington was not part of it due to its unique size. We’ve been evaluating data from both race packages, as well as feedback from drivers, teams and OEMs and feel that the 750 hp/low downforce package best fits the track.”

Overall, the rules package will generally remain the exact same in 2021, as teams look to build off their knowledge and experience from the race package in 2020 while preparing to transition over to the Next Gen car for 2022.

The three new road courses on the NASCAR Cup Series schedule for 2021 – Circuit of The Americas, the Indianapolis Road Course and Road America — will be determined by the sanctioning body, with assistance from the OEMs through the use of simulations to determine which package will work best. The same method was used earlier in the season – and in a much shorter time frame — when determining which package to run at the Daytona Road Course, which was a late addition to the 2020 schedule.

In other changes, teams now must compete in a minimum of 16 points events with a short block sealed engine. This is increased from the minimum of 13 races in 2020. Teams will also be restricted to 150 Restricted CFD (computational fluid dynamics) runs per calendar month.


Aerodynamic Package Breakdown – 2021 NASCAR Cup Series (By Track):

750-horsepower: Bristol Motor Speedway (both oval and dirt), Charlotte Motor Speedway Roval, Circuit of The Americas, Darlington Raceway, Daytona Road Course (which the Busch Clash is running) Dover International Speedway, Indianapolis Road Course, New Hampshire Motor Speedway, Martinsville Speedway, Nashville Superspeedway, Phoenix Raceway, Richmond Raceway, Road America, Sonoma Raceway and Watkins Glen International.

550-horsepower: Atlanta Motor Speedway, Charlotte Motor Speedway, Auto Club Speedway, Homestead-Miami Speedway, Kansas Speedway, Las Vegas Motor Speedway, Michigan International Speedway, Pocono Raceway and Texas Motor Speedway.

Superspeedway: Daytona International Speedway and Talladega Superspeedway.

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