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So you were driving down the highway the other day when a Corvette sports car blew by you like you were standing still. The noise from its engine felt like it was going to rattle your windows right out of your door frames. There in the rear bumper you saw four separate exhaust pipes and you asked yourself, Why does a sports car need some many exhaust pipes? There is a mechanical reason, but you were likely looking at a stylistic choice.

Long story short: Expelling exhaust gases from the engineā€™s cylinders takes energy. If you take an older sports car with an undersized exhaust system, installing a larger diameter aftermarket system may actually increase your engine horsepower. This is because the higher capacity system has negative pressure and actually sucks the exhaust gas out of the cylinder when the valve opens after the combustion cycle.

Early hotrodders invented all kinds of improved exhaust systems. Some were shorter, exiting out of a carā€™s fenders. Others had larger pipes or multiple pipes to increase flow. Manufacturers quickly caught on and began to increase the size of the exhaust systems for top trim sports cars. For some models you can tell the size of a carā€™s engine by the number of exhaust pipes exiting beneath the rear bumper.

Closeup of the four performance exhaust pipes on one side of a hotrod
Hotrod exhaust | RonBailey via iStockPhoto

As competition between automakers had grown increasingly fierce, many have dreamed up added features, such as how a car looks or sounds. There is an entire science to tuning the sound of an exhaust, based on the size of the muffler as well as the number and size of exhaust pipes. Automotive designers also choose to add more pipes or eye-catching chrome tips to the exhaust pipes just to make a sports car or truck look cooler.

The sports car that passed you on the highway would have been just as loud with one or two huge exhaust tailpipes as with four small ones. Its muffler was tuned to be that loud. The number of exhaust tailpipes sticking out of its rear bumper was a stylistic choice, the sort of over-the-top feature that separates Chevrolet Corvettes, Mercedes-AMGs, Lamborghinis, and Ferraris from the cars us mere peasants drive. But remember, most of those cars cost $100k or more. So a used Honda Civic, even with its measly single tailpipe, is a much better dollars/tailpipe deal.

Next, learn whether the spikes on semi truck wheels are safe, or see how some exhaust systems make more power in the video below:

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