NASCAR introduced a new rule package for its Next Gen Cup Series race cars, including the new Ford Mustang Dark Horse, that will make racing more competitive on short tracks and road courses, according to a report from NASCAR.com.
A bulletin sent to Cup Series teams on January 10th, 2024 outlined the inbound changes for NASCAR’s premier division, which will take effect at Phoenix on March 10th. Most notably, this includes a simplified rear diffuser with fewer vertical strakes, which will decrease downforce at the front of the race car by keeping the engine panel free of strakes. The splitter stuffers from last year’s rule package will remain in play.
In order to mitigate reduced downforce from the modified rear diffuser, the rear spoiler of the Next Gen race cars has been increased to three inches in height, up from two inches. The spoiler will retain the same length as previous years.
These changes will help keep racing more competitive at short tracks and road courses, where the Next Gen race car has struggled since its introduction in 2022. As part of the development process for the new diffuser and spoilers, NASCAR analyzed testing data from a session at Phoenix in December, where Ryan Blaney and Chris Buescher turned laps in the new Mustang Dark Horse race cars.
“One of the things going into the Phoenix test, we said, ‘let’s do a simplified diffuser,'” Dr. Eric Jacuzzi, NASCAR vice president of vehicle performance, said. “‘Let’s see what it does when we put it in traffic,’ and what we actually found was it appeared to be an improvement. Then another interesting effect was that it did not lose rear downforce when it yawed, which is an issue we fight with the current car. So we felt that the car, the drivers would be able to slide around more on the short tracks and really have to be less careful about putting power down.”