Founded in 1947, NASCAR is a young sport whose relative youth has not constrained its popularity. Fans flock to the tracks by the hundreds of thousands, an estimated nine million people regularly watch televised races and it generates billions of dollars a year. Given its popularity, it is undeniable that NASCAR has joined the ranks of baseball, football, basketball and hockey as a major American sport.
Of the major sports, only NASCAR directly involves machinery. The inclusion of machinery in racing has led to an increased focus on the science and technology that allow drivers to reach new levels of performance. The equipment has become so complex that some colleges (including Old Dominion University) now offer degrees in motorsports-technology. Other educational institutions such as the NASCAR Institute of Technology specialize completely in the technologies associated with racing.
How and why are technology, engineering, and scientific evaluation the cornerstones of the racing world? Ask any pit crew member, NASCAR engineer or driver and you're likely to get generalizations at best. For good reason, racing teams are very quiet about the details of their business. Secrets from optimal tire temperature to specifics about engine compression can potentially give a driver an edge. In a sport where races hundreds of miles long are decided by fractions of a second, any edge, however small, is carefully guarded. Read on to explore the scientific concepts and principles that govern the world of NASCAR.
Power
Although racecar engines are similar to the engines in normal cars, there are several significant differences. These help account for the fact that while an average consumer car produces between 150 and 200
horsepower, NASCAR cars can produce about 750. To understand how the extra power is generated, it is necessary to understand the basic mechanics of an engine.
There are two components that engines need to run: fuel and air. In a traditional
four-cycle engine, air and fuel are taken into a piston chamber and ignited. The energy from the explosion pushes the piston. This action is called the “power stroke” and is the fundamental power-producing function in a car.
Since this process is the same in race cars and normal cars, why is there a difference between the two? First, NASCAR cars use far more inputs. The part that feeds fuel and air to the engine is called a carburetor. In NASCAR cars, the carburetor allows far more fuel and air into a larger piston chamber. The result is a bigger explosion and more power. Furthermore, normal cars are equipped with catalytic converters and mufflers. These devices, which are part of the exhaust system, help clean the exhaust and reduce the noise, respectively. NASCAR vehicles have neither part. The lack of these parts allows air to flow through the system faster, increasing the air supply to the carburetor.
Friction
Friction is the force that resists movement when two touching objects move. Some objects moving against each other create little friction and some create a tremendous amount. Generally speaking, smoother things have less friction than rough things. Rubbing two coarse rocks together, for example, would produce a lot of friction. By contrast, rubbing two ice cubes together would produce very little.
In racing, there are three points where friction is most important: inside the engine, between the car and the surrounding air (
aerodynamics), and between the track and the tires. A key scientific principle in NASCAR racing is controlling friction.
Inside the Engine
As explained above, a car’s power is derived from the piston moving inside the engine. To get maximum power, this is the first place that engineers must reduce friction. NASCAR engine parts are far more finely machined than those in normal cars. The extra machining makes the pistons and casings much smoother. This reduces friction, which maximizes the
efficiency of the engine.
Aerodynamics
With cars traveling at about 200 mph in NASCAR races, the friction between the car and the surrounding air (called “drag”) is enormous. Friction is created because the car is moving through the air at high speeds. Essentially, the car must push the air out of its way. To help understand this concept, imagine putting your hand out the car window and feeling the wind push your hand back.
Your car on the highway is probably going about 60 mph, so you are experiencing the force against your hand at a low speed. NASCAR vehicles travel over three times faster, but they must deal with far more force because drag increases with the square of the speed. This means that if you go twice as fast, the drag increases by the square of two, or four. In this example, cars are traveling three times as fast, so the drag is nine times more severe. Because of this effect, most of the horsepower generated by a NASCAR engine is used to fight drag. In fact, NASCAR vehicles today run at near terminal velocity, meaning that regardless of the engine power they would be unable to travel any faster.
Where the Rubber Meets the Road
Good tires are essential for the success of any NASCAR vehicle. They are responsible for maintaining adequate traction during tight turns and producing enough friction to slow a car from 200 mph. Unlike normal tires, which have treads and are relatively hard, racing tires are wide and smooth, and made of a softer, thinner rubber. The reason they don’t have treads is to maximize the “contact patch,” which refers to the surface area of the tire that actually comes in contact with the track. When this area is larger, it provides the car with better traction.
Racing tires have certain design elements that make their lifetime relatively short. First, at only a quarter inch thin, they can wear out quickly. As mentioned, the tires are made of a softer rubber. In effect, this makes them stickier, which helps generate the friction needed to brake. The result of this special design is that drivers regularly go through ten or more sets of tires in one race.
See also:
The Social Science of NASCAR
NASCAR History: From Bootlegging to Big Bucks
