NASCAR settles on Next-Gen specs

The car William Byron drove in a two-day test at Auto Club Speedway this week is the car NASCAR intends to race next season.

While this week's was the fourth overall test for the development of Next Gen, the car that hit the track did so for the first time. Byron drove the third prototype vehicle, or P3, which NASCAR said was a model that is nearly 100 percent complete.

"This is a brand-new car," said John Probst, NASCAR senior vice president of racing innovation. "We didn't take any parts off the car we had at Richmond, Phoenix, and Homestead. Our goal was to take all the feedback we received from the first three tests and implement that into what we consider our pre-production prototype.

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"This is what we intend to race in 2021. What you see here today is a result of all the testing and input we've received."

A lot of the changes on the P3 prototype came from input from engineers and mechanics.

"The top of the front clip is a lot wider – a lot of feedback from the engine tuners from the early chassis is that it was difficult to get the valve covers off," said Probst. "We did some stuff in the rear clip to accommodate getting rear bars in and out easier. The move to the new wheel and hub necessitated some new uprights to be built. Those are really the highlights of what's different here."

Bryon is the fourth driver who has been able to test the car, and the second from Chevrolet. Fontana was the largest facility the vehicle has tested at.

"It was tough to get a hold of at first, just how fast everything is," said Byron. "The tire doesn't have the same sidewall, so there is not the same amount of slip that you can hang the car out. You just have to get used to that timing and rhythm of when the car does step out, how quickly you can catch it when it slides the front tires, how quickly does it come back. All of those things are different from what we do now. It takes some adjustment to learn from."

Bryon got out of shape on Monday but didn't hit anything. Tuesday, the test finished early after he hit the wall off Turn 2.

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"We were probably six or seven laps into a 25-lap tire run," said Byron of the incident. "I had been a little free for a couple of corners, but nothing major. That time, I just got loose and figured I'd be able to save it but wasn't able to. It just came all the way around. I had a number of similar moments in the race Sunday and was able to drive out of it. That's what caught me off-guard the most. It's part of testing, though, learning where the line is with what the car can do."

Crew chief Chad Knaus said he thought the car was "really cool" and a step in the right direction. However, there is still a lot to learn as an industry about what the car is capable of.

"It's significantly different," said Knaus. "You can liken it to the difference between working on a modern-day street car and working on a street car from the '70s or '80s. There is just a major difference in the type of stuff you can work on. The components are smaller and more nimble, and it's a lot more compact in the packaging of the car."

"What and when we can change things is going to be significantly different. What you would change at the track might change from what we're doing now – you're going to have different knobs to turn. The thing that's exciting about it is it's a brand-new entity, so we're always going to be learning new things about it and finding out what matters the most. It's still a race car, and we're still going to be able to work on it."

NASCAR plans to next test at Atlanta Motor Speedway on March 16-17.