NASCAR Cup Series

NASCAR's aerodynamic testing produces mixed results: 'It was not a home run'

Published Aug. 2, 2023 2:14 p.m. ET

RICHMOND, Va. — NASCAR took some steps toward trying to improve its short-track and road-course racing package during a two-day test, but it still has work to do to try to find the right aerodynamic and tire combination to produce the racing that fans were accustomed to over the last decade.

NASCAR had high hopes for the two-day on-track test Monday and Tuesday at Richmond Raceway as its wind-tunnel testing showed the changes had promise for the Next Gen car, introduced in 2022. In a nutshell, it decreased the size of an underwing piece at the front of the car and curved it in the center, which in theory would add lift to the car out front but increase downforce for the cars in traffic, making it easier to make a pass

Engineers had predicted that cars in the pack would run tight with the increased downforce added to the trailing cars.

But that didn’t happen. The cars were loose, sending NASCAR down the path during the test of removing more underwing pieces — the entire rear diffuser — while adding two inches to the spoiler, using the same 4-inch spoiler it uses at most other tracks.

Those unexpected changes showed some potential gains, mostly on a tire that had a thicker top layer in the amount of rubber used. There was nothing extraordinary about the testing results for the six drivers participating over the two days, more of learning what direction to go in for future testing.

"We got some positive comments that the diffuser not being there made the car a little more forgiving on corner entry," NASCAR Vice President of Vehicle Performance Eric Jacuzzi said. "They felt like they could slide around a little more and move around a little more. We were pretty happy with that."

Drivers told FOX Sports that they felt the biggest difference maker was the tire, not necessarily any of the aero changes on the car. At the end of a tire test in a couple of weeks on the Indianapolis Motor Speedway oval, NASCAR will take off the diffuser to see whether that makes a big impact. Jacuzzi said they can learn about the short-track package at the massive 2.5-mile IMS oval because the track itself is so narrow, but the changes being contemplated are likely just for short tracks and road courses in 2024.

NASCAR obviously had hoped for a little bit more convincing of results.

"It was not a home run," said Joe Gibbs Racing driver Christopher Bell after the first day of testing. "This did not feel like a big difference. ... I applaud NASCAR for trying. It’s cool [to see the pieces] but I didn’t notice anything."

Christopher Bell explains how the car felt during the short-track race test at Richmond

NASCAR had taken its new pieces to the wind tunnel a few weeks ago and many in the industry were optimistic from what they saw in the wind tunnel data. It showed total downforce of 50 percent of what drivers raced with Sunday at Richmond.

"In the wind tunnel, we showed the same thing as in [computer analysis] that the car behind would have a slight advantage to neutral," Jacuzzi said. "It’s a little baffling to not get that, but there are a lot of moving parts on the track."

NASCAR tested three variations with various ride heights and downforce levels Monday. In the sessions, they would do 15-lap or 30-lap runs and then have the car at the rear of the field start on the pole for the next segment.

Noah Gragson couldn’t make a pass and was last in one segment Monday and then, when on the pole, drove away from the field on the next segment.

"I started the first 15 laps in last and I couldn’t do anything with it and the car was super disconnected," Gragson said. "And then I got out front and it was like a completely different race car — it was super gripped up and all my problems were fixed and I drove away with the lead."

"It's a lot of trial and error," said Noah Gragson on the mini races of the short-track test

Gragson said he actually asked his team at one point if the car had the current splitter on it rather than the test splitter because he didn’t feel any difference.

"It’s a lot of trial and error," Gragson said. "Right now. we're just trying to learn and come up with something — we're trying to figure it out. We're not going to hit on it right away, but that's kind of what we learned."

The whole point of testing is to put theory into practice, and it isn’t all that rare that not everything goes as hoped. Short-track and road-course racing had been some of the most exciting racing in NASCAR for several years, but the new Next Gen car has not provided dramatics as drivers have had difficulty passing.

The racing on ovals bigger than a mile has improved, and NASCAR continues to search for ways to improve the ability of these cars on the short track.

"A lot of feedback from drivers was it wasn't quite enough," Jacuzzi said. "There was some good learnings. Obviously, we wanted a grand slam and didn't get that."

At their debrief following testing Monday, the drivers suggested the additional aero changes for Tuesday.

"I feel like we just need more lateral [grip] to be able to make passes and set people up and get runs off the corner," Byron said. "I feel like we're all pretty limited on lateral especially when we went to this package. It just makes it hard to hustle a car and get beside somebody."

William Byron on how the car felt at the short-track test at Richmond

One of the problems on short tracks is that drivers can use shifting as a defense mechanism. If they don’t get through the center of the corner as fast as the car behind, they can shift and accelerate sooner to remain ahead rather than the trailing car using its momentum to complete the pass on the straightaway.

There also is hope that a softer tire could improve the racing. The teams tried five different tires — including the ones used at Richmond for races this year and then a new tire that debuted at New Hampshire as baselines — during the test.

"We want the tires to fall off but have some lateral to start the run," Byron said. "And it doesn't seem like we're able to start the run with much grip and reserve so that you can maybe save or do some different things [such as] back off your pace and then advance at the end of the run."

They got a little bit of difference with the last set of tires they tested Tuesday.

"You could follow pretty well," Gragson said after the second day of testing. "Tucked up right behind somebody, [it] felt a little bit more like super late model racing, short-track racing where you could stay right behind the guy and kind of move them up out of the way and drive underneath them. I thought there was a lot of gains there."

Drivers run the short-track race test at Richmond

So what’s the answer?

"We’ve got to keep working on this," Jacuzzi said. "It's not going to fix itself."

Bob Pockrass covers NASCAR for FOX Sports. He has spent decades covering motorsports, including the past 30 Daytona 500s, with stints at ESPN, Sporting News, NASCAR Scene magazine and The (Daytona Beach) News-Journal. Follow him on Twitter @bobpockrass, and sign up for the FOX Sports NASCAR Newsletter with Bob Pockrass.

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