Exhaust, ride height top NASCAR's worry with COT

MARTINSVILLE, Va. -- Brian Vickers suffered burns on his feet and backside. Denny Hamlin has been battling headaches. Matt Kenseth has felt sick all week.

The Car of Tomorrow is supposed to be the safest vehicle ever used in NASCAR, with a larger cockpit area and side panels lined with energy-absorbing foam. But some drivers were exposed to dangerous carbon monoxide fumes when their exhaust systems failed in last week's debut at Bristol, Tenn., forcing crews to scramble to rectify the problem before Sunday's event at Martinsville Speedway.

It's the most obvious tweak to the COT, which enters its second week after receiving mixed reviews from drivers and cautious praise from NASCAR for its performance last week in Bristol. Officials liked the way the front end held up in competition, the relatively small difference in qualifying times from first to last, and the presence of some smaller teams in the top 20.

But they're also shifting 50 additional pounds to the right side of the cars to alleviate a sticking point the majority of the teams ran across in inspection. They're working on minimum and maximum height procedures. And they're trying to rectify exhaust systems that failed at Bristol and made some drivers sick.

"The exhaust, I think, is the first thing everybody went to work the hardest on, because there were probably more exhaust failures than what we know we need to see," said Nextel Cup director John Darby. "So in just a week's time walking through the garage and looking at the cars [Thursday], tailpipe configurations and the material that they're constructed out of has changed dramatically."

Carbon monoxide is noxious stuff -- driver Rick Mast was forced to retire in 2003 after poisoning from the fumes left him nauseous, ill and unable to withstand exhaust of any type. Vickers suffered minor burns and carbon monoxide inhalation halfway through last week's race after a piece of exhaust tube near the front of the car broke off, crew chief Doug Richert said. Hamlin suffered a cracked exhaust pipe in practice, and began suffering from headaches late in the race even through the damage had been repaired prior to the event.

"We can't directly relate it to carbon monoxide. We thought maybe it was a possibility, given that I picked up a real bad headache halfway or three-quarters of the way through the race," Hamlin said. "... But Bristol has always been bad anyway. Because you're inside of a bowl, you've got all the exhaust from the cars running, all the generators from the tractor trailers running during the race, nothing can escape. It's all inside the bowl right there."

Hamlin said his personal trainer called the trainers of other Nextel Cup drivers and found that several of their clients had skipped scheduled Monday morning workout sessions because they weren't feeling well. Kenseth suffered a double blow, with a cracked exhaust pipe melting a basketball-sized hole in the absorbent foam of his No. 17 car.

"Half of our door foam was burned up, and we had a hole in the carbon fiber and I had to breathe that stuff all day," he said. "So that's definitely a big concern for me, especially this week and in the future as we get in the cars with right-side windows. That stuff burning, I don't care what they say, whenever you take something man-made like foam and all that stuff, when that stuff melts and burns, I know the fumes and smoke coming off that can't be good for you."

Kenseth said NASCAR officials told his team the foam was installed improperly, something the No. 17 crew refutes. Darby added that some teams neglected to add the false floor that supports the foam above the tailpipe area, causing the foam to melt when it was exposed to the additional heat of the broken exhaust system. Another issue was the thinner material some teams used to build their exhaust pipes.

"If you looked at the materials that were used to construct tailpipes on our old cars, they ranged probably from 83-thousandths [of an inch] in thickness to 120-thousandths in thickness if you really wanted a robust system," Darby said.

"The majority of the tailpipes that failed last week were constructed of either 49-thousandths or 65-thousandths, thin material. So I think that because the tailpipe configuration is smaller and weighs less, a lot of the teams felt like they could probably get by with a thinner overall material. In fact, when you apply the heat of the exhaust and everything, they did crack and they did fail."

Attempting to avoid a repeat of last week, Kenseth's crew planned to install an additional heat shield and further space out the exhaust pipes off the frame rail. Other drivers like Jimmie Johnson take the additional step of breathing pure oxygen before and after an event in an attempt to flush the carbon monoxide from their bodies. Johnson takes it for a hour Friday, an hour Saturday, an hour Sunday before the race and an hour afterward if he can.

"That's really when you feel it the most," Johnson said. "Going into an event, you're usually hydrated, you aren't feeling too bad, you have had a chance to recover. The biggest things really come after the race, if you can get on some oxygen. It helps you out a lot."