Stock Car Aerodynamics - Bad Air?

Says Sadler, "It is a tough situation, but I think aerodynamic parity has been good for the sport. It allows us to race closer together."

But that close racing also contributes to what's become known simply as "the big one," the almost signature wreck at superspeedways that can take out a third of the field in one crash.

"I think drivers become frustrated, not because they are not able to pass, but because we are in a tight pack all day long ... You feel like you are glued to each other ... 43 cars are glued to each other," Sadler says.

Busch's NASCAR debut as a professional was in the 2000 Craftsman Truck Series race at Daytona. Compared to the sleek bodies on a Winston Cup car, the trucks look like they have all the aerodynamic refinements of a trackside war wagon. But around Daytona, the trucks will turn faster qualifying times and races usually include many more on-track passes than a Cup race.

"It's all horsepower," Busch says. "Sure the trucks don't have the aerodynamics of a car, but with 650 horsepower compared to what's available in a restrictor plate Cup engine (approximately 400-plus) the trucks just produce a more exciting racing environment on that track. The trucks are slowed down because of all that drag, but they have the horsepower to overcome it.

Some drivers have suggested that NASCAR should find a way to reproduce the truck aero figures on Winston Cup cars and turn them loose without restrictor plates. Nelson counters that each time you add more drag to the cars, you will end up with more downforce. "You can't just change one thing," he says.

Don't expect to see any radical change in the next year that will alter the level of competition. Look, instead, for a gradual reduction in aerodynamic downforce.

Nelson said by reducing total downforce, he hopes to lessen the impact of taking air off the front or rear of the car. "If you have 400 pounds of force on the nose and you lose half of it, it will be a more severe change than if you have only 200 pounds or 100 pounds and lose half of that number," he says.

If you reduce the aero downforce, the cornering speeds should get slower, which should mean there is more power available coming out of the corners (right now on big ovals cars are cornering at nearly full power) and that will create opportunities to pass.

Some of the reduced downforce could be generated by the proposed taller greenhouse, which not only may create more lift by accelerating the air as it goes over it but also divert air that now goes to the rear deck spoiler.

Other things will have to change also. Today's Goodyears work so well at the current levels of downforce that the tire maker may have to create one that will work as well at reduced loads.

"The thing is that when you look at the three elements-engines, aero, and tires-when you bring those things under control, then races are won by things we can't control," Nelson says. "That puts the emphasis on the drivers and the teams willing to work harder. It becomes the human element that wins races. That's really how races should be won."

While wind tunnel testing is the most common way to gauge the aerodynamic efficiency of a NASCAR race car, there is an alternative to tunnel testing, and it's done in the middle of the Arizona desert.

Since the mid-'90s, NASCAR teams have used one of several manufacturer-owned desert proving grounds locations in the Phoenix area. Teams aero test in the desert primarily because it offers a moving road surface (ground plane), the one thing that full-size wind tunnels in North America lack.