CONCORD, N.C. -- NASCAR spent almost the entire year developing its 2013 car in hopes the "Gen 6" model will dramatically improve the racing.

After his first test drive Tuesday, NASCAR's most popular driver approved of the car.

"This sport is going to be revolutionized again with this car," Dale Earnhardt Jr. said.

That's a ringing endorsement for NASCAR, which stumbled out of the gate with the launch of its 2007 car and never recovered. Drivers were mixed on the "Car of Tomorrow" during its development and the messaging reflected the varying opinions.

When Kyle Busch won the CoT's debut race at Bristol, he panned the car in his victory celebration on live television. He didn't let up in his post-race interviews, likening the car to driving a milk crate, and the car was forever tainted with fans. The CoT was finally retired in last month's season finale.

NASCAR has worked tirelessly this year on orders from chairman Brian France to develop a racier 2013 model, which will officially debut at the season-opening Daytona 500 in February. It's been tested some over the fall, but Charlotte Motor Speedway opened Tuesday for a two-day session attended by 16 drivers.

Among them was Earnhardt, who won 17 races in the "old" car but only two after the CoT was introduced in 2007.

"I think the car has really awesome potential, and I like it already leaps and bounds beyond the CoT," he said. "This car really gives me a lot of sensations that are similar to the old car that we ran 10 years ago. The CoT was just frustrating for me. I had good runs and good races in it and I had races where the car drove well, but I never really connected with that car from the very beginning. Just personally, I didn't really like the car for what it was."

NASCAR strived to give the manufacturers brand identity with the 2013 cars in an effort to make them resemble what the automakers are actually selling in the showrooms.

Reigning Sprint Cup champion Brad Keselowski made his debut in a Ford while Matt Kenseth switched to Joe Gibbs Racing and Toyota after 13 years in a Ford with Roush Fenway Racing.

Kenseth tweeted a picture from inside the car, where a Darth Vader mask hung from rearview mirror, and he made a joking reference to moving over to the dark side. Kenseth later admitted to being anxious before arriving at the track and he over-revved his engine before the lunch break, forcing the No. 20 crew to swap engines.

Keselowski, back from a brief vacation after collecting his Sprint Cup trophy in Las Vegas, had a whole new look as champion.

Penske Racing switched from Dodge to Ford, and with the manufacturer change came a new paint scheme and firesuit for Keselowski, who is still tinkering on a final design. After sporting a predominantly blue look the last three years, his new schemes have a heavy white presence.

Keselowski was also working for the first time with new teammate Joey Logano. The combination of a new car and a new teammate made this first test critical for the champion.

"I think all the signs are there that we have the potential to be just as strong, if not stronger, than we were last year, which is very, very encouraging," he said. "It's been a lot of fun having the first day working with Joey, which I think has been probably more of an adjusting process than the actual car itself, and a good adjusting process. I'm curious to see over time how we can work together and push each other to be the best we can be. We've got a lot of work to do."

Copyright 2012 by The Associated Press. All rights reserved. Material may not be redistributed.

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