Explainer

How Do You Cheat at NASCAR?

Auto racing’s dirty tricks.

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With the Daytona 500 less than a week away, four crew chiefs were suspended yesterday after inspectors discovered modifications to their cars that violated NASCAR rules. The cars apparently had holes drilled in the wheel wells and in the back to make them more aerodynamic. How else can you cheat in auto racing?

Let us count the ways. Car technicians and crew chiefs are constantly devising new tricks to make their cars go faster. But occasionally their methods will be a little too innovative. In most auto-racing leagues, cars undergo inspections before and after every race and qualifier. Every sanctioning body, be it NASCAR, Indy Racing League, or the Sports Car Club of America, has its own set of rules about size, shape, and weight. In NASCAR, for example, the distance between the centers of your tires has to be exactly 110 inches, and fuel tanks are normally limited in size to 22 gallons. In general, cheaters use three methods to make their cars go faster: They improve its aerodynamics, increase the amount of oxygen that gets to the carburetor, or boost its fuel capacity. (Most of the cheats outlined below are now well-known to racing inspectors and are therefore used less and less.)

There are a number of ways to make the air flow around a car smoother. (Putting holes in the wheel wells, for example.) Normally, NASCAR drivers are required to keep the front windows down, so they can get out in case of an accident. That means a lot of air gets trapped inside, creating drag. In the past, some drivers would cheat by rolling up the windows during a race, only to roll them back down each time they drove past the officials. Another option is to tinker with the size and shape of a stock car’s spoiler—a sloped fin in the back that manipulates air flow to push the car down onto the track. (This improves both traction and handling.) Crew chiefs are often penalized for making spoilers too high, which increases the downforce. But some engineers have supposedly evaded inspectors by designing spoilers with a special material that changes shape at high speeds and reverts when the car slows down.

To increase fuel capacity, some cheaters have used long tubes to connect the fuel tank to the engine. So instead of, say, 5 feet of tubing, they’ll coil up 20 feet—which may add a couple extra gallons of fuel capacity. And more fuel capacity means you don’t have to stop to refuel as often. Increasing oxygen flow to the engine is trickier. You can tinker with the NASCAR-mandated restrictor plates, which limit the amount of air that gets in for safety reasons. (Without the plates, cars can reach dangerous top speeds of more than 200 miles per hour.) You can also juice up your fuel: Some racers used to add oxidizing chemicals, which at high temperatures would release oxygen into the engine and improve performance. These days, inspectors keep a close eye on fuel, making this method uncommon among professionals.

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The Explainer thanks Jerre Hill of the University of North Carolina in Charlotte and Peter Hylton of Indiana University-Purdue University Indianapolis.