The National Association for Stock Car Auto Racing, or NASCAR, was founded in the United States in 1947. Throughout its early years, NASCAR was a series of automobile races that involved vehicles that bore a very near resemblance to the vehicles then being produced for commercial purposes in post World War II North America; the typical NASCAR race vehicle was a factory manufactured sedan.
"Stock" is the term employed throughout all motor sports to signify vehicles that have not been significantly modified in terms of the size and displacement of the engine, suspension, or transmission. Stock is often employed in the same circumstances as the expression "street legal," a phrase meaning that the vehicle in question complies with the rules respecting highway operation in a particular jurisdiction.
The first NASCAR races in the late 1940s and early 1950s attracted a significant following, particularly in the southeastern United States. Many of the races were often contested on dirt track ovals, where the competitors raced 0.5 mi (0.8 km) for each lap. NASCAR racing took a significant step forward with the construction of its super speedways, the most notable of which was built at Daytona, Florida in 1953. NASCAR racing gradually moved away from its stock format to vehicles built for the specific demands of racing in to the late 1950s; the development of the 355 cubic inch displacement V8 engine by General Motors was one of the early landmarks of that progression.
Modern NASCAR is a sport that enjoys a strong following in North America, and a steadily growing international fan base. NASCAR successfully marketed its racing product on a combination of the vehicle performance, the nature of NASCAR racing (which requires the drivers to operate the vehicles at very close quarters to one another at speeds that frequently exceed 150 mph (241 km/h), which sometimes leads to relatively frequent and spectacular collisions), and the personalities of the successful drivers. "King" Richard Petty became a NASCAR icon, especially as he was followed into racing competition by a son and a grandson. Junior Johnson, Dale Earnhardt, and Rusty Wallace attained similar levels of public acclaim. North Carolina and the adjacent southern states have remained the epicenter of NASCAR, as a number of highly regarded tracks are located in the region; many of the prominent racing teams are also headquartered in the vicinity.
The modern NASCAR race vehicles have a silhouette similar to the production vehicles built for commercial sale by their sponsors. Beneath the outer shell of the vehicle, the NASCAR race car is a combination of high technology and older styled automotive features that are mandated by NASCAR rules. These machines are capable of speeds in excess of 200 mph (322 km/h) on a race track straight away. The driver is secured within a roll cage through a series of safety mechanisms, designed to deflect the forces of collision away from the driver's body. With the rise in the television appeal of NASCAR, most of the vehicles are equipped with on board television cameras that provide a view both of the driver as he operates the vehicle, as well as a vantage point on both the movements of opposing drivers and any the collisions that occur during the race.
The typical NASCAR race car is powered by a V8 engine, built to run at high speeds in warm weather conditions without failure for several hours at a time. Each engine is capable of producing as much as 750 horsepower, with an engine design that forces much larger quantities of air into the engine for combustion than does a conventional engine design. The carburetor, the mechanical device that mixes the required amounts of air with fuel in an internal combustion engine, is a "low tech" instrument in the face of modern technology such as fuel injectors; NASCAR rules prohibit fuel injector use. As a result, large amounts of air and fuel can be mixed, increasing the potential power to be generated by the vehicle.
A NASCAR team will employ two different body types in a racing season, depending upon the length of the track. On short tracks, where the circuit is fewer than 0.75 miles (1.2 km) in length, the racing teams seek a vehicle that will handle the tighter turns and the shorter straight-aways in an optimal fashion. In such conditions, vehicles handle best when they are able to generate down force, the physical quality achieved where the aerodynamics of the vehicle force it closer to the surface of the race track when traveling at high speeds. Down force permits greater handling characteristics in the tires while cornering, which allows for greater vehicle speed on these shorter courses.
NASCAR places technical limits on engine capability at the longer, super speedway courses, where there are longer straight-aways and a consequently greater risk of high speed collisions. The most prominent of these tracks are Daytona and Talladega. The most effective of the limitations is the mandatory use of restrictor plates on the super speedways. The carburetor mixes fuel in vapor form, with air directed
The restrictor plate is a metal barrier with a pattern of holes drilled through it that is placed between the intake manifold and the carburetor. The plate restricts the flow of air into the carburetor, creating a smaller available volume of fuel and air to be mixed and combusted in the engine, reducing available engine power and speed.
All NASCAR racers are constructed with a number of aerodynamic features. The most obvious of these are such items as the air dams (the skirting that extends from the body of the vehicle encircling the structure except for the wheels) and rear spoilers (the wings attached to the rear of the vehicle to assist in producing down forces that push the vehicle closer to the road surface and enhance stability, especially when moving through a corner at high speeds. In addition to these features, standard NASCAR race tactics include drafting behind a lead vehicle. Drafting is the procedure where a driver positions his vehicle directly behind the lead vehicle, so as to take advantage of the partial vacuum created by the lead vehicle movement through the air. By positioning the second vehicle on the bumper of the first, the second vehicle is essentially pulled through the partial vacuum by the lead vehicle. It is common in NASCAR races to see multiple vehicles drafting, one after another.
In contrast to open wheel racing such as Formula 1 Auto Racing, the driving tactics of NASCAR are usually less complex, as the NASCAR circuits are almost always an oval with all vehicles heading in an identical fashion for between 200 and 600 mi (322-966 km). Drafting at very close quarters, the bumping of vehicle ahead to gain an advantage, and very daring passes at high speeds on banked turns are standard driver practice.