Las Vegas - Denny Hamlin was fined $25,000 by NASCAR on Thursday for criticizing the new Gen-6 race car after last week's race at Phoenix, and the furious driver said he won't pay.

Hamlin compared the new race car unfavorably to last year's car after his third-place finish, angering NASCAR officials who are concerned about the Gen-6 car's public perception. Although Hamlin's brief comments were barely noticed last weekend, NASCAR leveled a significant fine against him.

"Ultimately, I'm not OK with it," Hamlin said outside his hauler after the morning test. "This is the most upset and angry I've been in a really, really long time about anything that relates to NASCAR.

"The truth is what the truth is, and I don't believe in this," Hamlin added. "I'm never going to believe in it. And so as far as I'm concerned, I'm not going to pay the fine. If they suspend me, they suspend me at this point."

Hamlin might not have a choice: According to NASCAR rules, unpaid fines may be deducted from a driver's purse or point fund earnings.

NASCAR vice president of competition Robin Pemberton said Hamlin is allowed to appeal his fine, and NASCAR apparently isn't in a rush to collect it. Section 12 of the NASCAR rule book states fines must be paid "promptly," but gives no specific time frame, and says unpaid fines "may result in suspension."

"We give them quite a bit of latitude, but you can't slam the racing," Pemberton said. "You can't slam the product. That's where it crosses a line."

Hamlin ran well last Sunday in the second race for NASCAR's new Gen-6 race car. He was asked on pit road after how he liked the car, and said: "I don't want to be the pessimist, but it did not race as good as our generation five cars. This is more like what the generation five was at the beginning."

NASCAR deemed Hamlin's remarks as detrimental to stock car racing, saying that while drivers get "ample leeway in voicing their opinions when it comes to a wide range of aspects about the sport, the sanctioning body will not tolerate publicly made comments by its drivers that denigrate the racing product."

That didn't help Hamlin's bewilderment at his fine in a sport known for frank talk about every aspect of competition.

"It's an opinion. It's not even a bad one," Hamlin said Thursday. "I don't want to make things worse than they already are, and this is something that was absolutely nothing that got blown into something, and it's just going to be worse for them, so just let them deal with it."

The Gen-6 car was developed by NASCAR last year with heavy input from the manufacturers to improve the on-track product. Drivers have been asked to be careful in how they publicly discuss the car, and NASCAR has put together a tremendous marketing effort in an attempt to avoid the poor reception the previous model received.

Fans never warmed up to the "Car of Tomorrow" in part because drivers panned it from the very beginning. Kyle Busch won the debut race in the "Car of Tomorrow" and blasted it in Victory Lane, and the car never stood a chance after that. Hamlin's comments came after the second race of this season.

"We're so early into it," Pemberton said. "You're making a mistake if you comment on the worst or the greatest racing ever. The first part of the season, we run on so many different racetracks, and we're so busy. ... Positive or negative, you cannot read too much into any of this stuff."

It's not the first time Hamlin has been fined for voicing his opinion. NASCAR privately fined him in 2010 for posts he made on Twitter about cautions.

At the time, NASCAR was secretly fining drivers for making disparaging comments about the racing product, and Hamlin's fine eventually became public as part of a push for the sanctioning body to be more transparent.

"I'm not going to say anything for the rest of the year, as long as it relates to competition," he said. "I mean, you can ask me how my daughter is, talk to me after wins about what have you, but as long as it relates to competition, I'm out from here on out. The down part is I feel like I've been a pretty good spokesman for them, and being positive when things aren't always positive. They just lost one small spokesman today, that's all."