Officials, teams to evaluate potential Next Gen aero, exhaust updates in two-day test at Phoenix

NASCAR competition officials have scheduled a two-day test this week at Phoenix Raceway to evaluate potential updates to the Next Gen car’s rules package, including possible aerodynamic alterations, trial runs using mufflers for select races, and efforts to curb rubber buildup in wheel wells.

Six Cup Series teams are scheduled to participate in the testing sessions Tuesday and Wednesday at the Arizona oval. Officials plan to divide the test days into five sections — an initial practice run with the current rules configuration to establish a baseline, and then four additional sessions with different combinations. The changes are intended to improve the quality of racing on road courses and oval tracks measuring 1 mile in length or shorter, but officials indicated that any benefits found on those courses should carry over to all track types.

Teams, drivers and officials will aim to assess any aerodynamic improvements in traffic and passing ability through changes in the car’s floor, or underwing. The updated underside uses some facets that have been developed in the Garage 56 Le Mans project’s test car, reshaping the area behind the engine panel and extending the diffuser strakes downward but leaving the current splitter in place.

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Dr. Eric Jacuzzi, NASCAR Vice President of Vehicle Performance, says that computer modeling of those changes created more downforce overall, but that those demonstrations also showed a radical difference in traffic behavior. “It doesn’t lose as much front downforce when it’s behind another car, so it doesn’t push as it gets closer,” Jacuzzi said.

To offset the additional downforce, three of the four new trial configurations will evaluate the use of a smaller rear spoiler — reduced from the current 4-inch height to a 2.5-inch size. It’s a potential change that’s supported by anecdotal driver feedback and data analysis; this week’s real-world test at Phoenix should provide another measuring stick.

“You can tie it back to if you watch the cars run on the track, right? You notice they run ‘nose up’ a lot, and it’s because the more air you can put to the diffuser, the more downforce it makes in the back,” Jacuzzi says. “So we made these changes that put more air to it, so that lets us knock the spoiler height down and still be at roughly the same downforce that we were at the start of the year. We assume that teams have gained a little bit, just optimizing where they can build things. So we’re roughly in the same spot that we were at the start of last year, but with a much smaller spoiler.”

The test’s second day will also explore the potential use of exhaust mufflers to reduce engine noise for two unique events set in metropolitan areas — the Feb. 5 Busch Light Clash at the Coliseum in Los Angeles and the inaugural Chicago Street Race in the Windy City’s downtown. Jacuzzi said competition officials do not have a projection in mind for the sound reduction, “other than to not impact the engine such that it needed to be mechanically altered, so any changes they need to make will be electronic — tuning and things like that.”

Jacuzzi says he expects mufflers to create a 6-to-10-decibel decrease, which would be a small but significant number in the car’s sound. But he also was quick to add that officials would take care not to lose the V8 rumble that has been a trademark of the fan experience.

“It’s a little less harsh,” Jacuzzi said. “It’s still going to be loud, and you should still wear ear protection, all those things, but it’s just going to knock some of that edge off. It’s not quite as aggressive, but it’ll sound the same.”