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Sports Then and Now

The Difference Between Race Cars and Street Cars

Posted on January 13, 2016 by Martin Banks

Stock car racing got its name from the early days of the sport, when racecars were strictly stock cars from the factory that had a few performance and safety tweaks. The stock cars we watch today have come a long way from their ancestors, constantly improving and resetting the standards of racing.


How do today’s stock cars differ from what you can buy from the factory? There are several major differences:

The Engine

For comparison, we’ll use a NASCAR engine. NASCAR engine blocks are custom-made, not modified from the original engine block. They do, however, share some similarities with the original. They have the same number of cylinders, the same base displacement and the same cylinder bore centerlines. Where NASCAR engines stand in stark contrast to regular engines is in the power – they’re consistently modified so they can produce the maximum.

One main difference comes in the NASCAR engine’s cam profile. It’s designed to keep the intake valves open longer, which means more air can be packed into the cylinders. More air and fuel is let in through the use of carburetors, unlike street cars, which mostly use fuel injection.

Both the intake and exhaust are modified so they provide a boost at certain speeds. The exhaust is exposed, with no muffler or catalytic converter to slow it down.


The subsystems of the car, including all of its pumps and alternators, can function at continuous high speeds and temperatures.

Finally, every part of the engine is made to exact dimensions to enhance power and reduce wear.

The Safety

Safety is a top priority for most automakers when they design street cars. They must meet certain crash safety ratings from the NHTSA, and many include air bags packed into every possible space.

A NASCAR driver has no airbags. Instead, they’re buckled in by a five-point harness and wear a mandated helmet. This setup is superior to a standard seatbelt. The seat is placed more toward the center of the racecar, so if the sides do get punched in, the driver has a better chance of remaining safe. A steel roll cage encapsulates the vehicle, designed to withstand brutal impacts should the car flip upside-down.

The Tires

While both kinds of tires are designed with performance in mind, racing tires have a relatively quick lifespan. Most last about 75 miles, whereas regular tires can last up to around 10,000 miles.

When you look at the main functions of each tire, it makes sense. Racecar drivers want tires that can handle extremes such as high forces, incredibly hot temperatures and fast speeds over short distances. A regular driver just wants tires that last.

Unlike regular tires, which are made out of rubber, racing tires are typically made from a polymer compound with a dual layer of carbon.

An obvious differences between the two kinds of tires is the tread. Regular tires have treads to provide grip in inclement weather. When racecars race in dry weather, they use slicks, which provide more surface area to make contact with the road. This enhances the grip.

Sometimes, racing tires are filled with nitrogen instead of oxygen, which increases the tire’s lifespan.

The Features

When you buy a car, one of the most exciting parts is all the features that come with it. The radio, the sound system, the built-in navigation, the tinted windows and the interior fabric are just a few items that may fit your fancy.


Of course, a racecar has none of these. It doesn’t even have a cup holder, and the windows are never tinted. All you get is a custom-molded seat that doesn’t adjust, the few gauges on the dashboard, the steering wheel, the transmission and the accelerator. Going more than 200 mph should be a feature in itself – racecar drivers really don’t need much else.

Now that you know the main differences between a street car and a racecar, get yourself to a race and watch the differences in action!

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