NASCAR: How Much of a Stock Car is Stock

Although the word NASCAR stands for National Association for Stock Car Auto Racing, this title and the term “stock car” can be quite misleading to those unfamiliar with the sport. When NASCAR first started in the late 1940s, the drivers would go to the local dealership, purchase a new car, strip it down to get it race ready, and then take it to a NASCAR sanctioned event to compete. These were actual “stock” cars with the drivers often driving them to the race to compete and then, if the car was still in drivable condition after the race was over, using the same race car to drive home, and possibly pick up the kids from school on Monday or make a grocery run one day during the rest of the week.

Today, however, the term “stock car” is simply a holdover from those earlier days. Is there anything about a current NASCAR race car that could be considered “stock?” With the exception of a few nuts, bolts and some screws, the answer would have to be no.

The modern race car competing on the NASCAR circuit today is basically completely handmade and comes with a price tag of upwards of $125,000 to build. This includes at least $70,000 for the body, chassis and frame, $40,000 or more for each engine, and more than $15,000 in labor costs. Needless to say, you won’t be finding any of these hot rods for sale in your local dealer’s showroom or on his lot.

Let’s take a look at the basic components of today’s “stock car.”

The frames of each car are usually prefabricated and each team purchases them from a frame supplier. The frame is designed and built for the safety of the driver as well as to hold up to the constant forces that racing produces.

The body of the car is largely handmade in each team’s shop out of flat sheet metal and takes about ten working days to produce. The only exceptions to this are the roof, hood and decklid which are usually purchased from a factory supplier. While the body may resemble somewhat the make and model of car you have in your driveway, there is really nothing stock about it. Each piece is hand shaped on an English wheel to exact NASCAR specifications. Each team must use NASCAR approved templates to measure all body parts to make sure they don’t exceed the specified tolerances that NASCAR has decreed to be appropriate. In addition, not all cars are built to the same specifications. Some cars are designed specifically for super-speedway use while others are designed for optimal performance on the short tracks.

The engine block itself is actually based on an original factory design for each make of car, but they are still custom made. They do have the same cylinder bore centerlines and start out the same size as the original, but the size increases somewhat during the process of assembling the engine. Each engine produces at least 750 horsepower with engine cams that are designed to open the intake valves sooner and keep them open longer than in the average street car. Other components custom designed for racing include the intake and exhaust systems, carburetors instead of fuel injection, programmable ignition systems, and various subsystems like coolant pumps, oil pumps, steering pumps and alternators.

The tires used on the car are radials just like on your passenger car but that is where the similarity ends. The tires are treadless due to the need to increase the amount of rubber contacting the track. This works great on dry tracks but can cause the cars to hydroplane if the track is wet. Thus, you will often see rain delays or cancellations in NASCAR when too much moisture is present on the track. The tire compounds vary and are regulated by NASCAR at each race due to safety. Each compound is different depending on whether the tire is used on the left or right side of the car and due to the design of the particular track. Teams must run the mandated compounds for each tire that is placed on the car. The tires also have an inner liner which is basically a second tire mounted inside the first. If the outer tire goes flat or blows out, the inner liner will hopefully allow the driver to maintain some amount of control and help bring the car to a safe stop. In addition, most teams inflate the tires with nitrogen instead of air due to nitrogen’s lack of moisture. Any moisture in the tire will vaporize and expand when the tire heats up, causing a pressure increase. Any changes in pressure, even though they may be small, can dramatically affect the handling of the car.

This has been just a brief overview of the NASCAR Stock Car. As you can easily see from even the limited information above, there is nothing “stock” about a modern stock car. So, if you are thinking of taking your new Impala, Fusion, or Camry to the nearest NASCAR event this weekend, I would strongly advise you against it. You will need large amounts of money and expertise to get out on that track and be competitive. Save the car in your driveway for picking up the kids from school or making the grocery run. The days of building a “stock car” in your personal garage or out in the barn are long gone.