The stock exhaust on many carsis far more restrictive than it needs to be. Many years ago people seeking improved power and performance learned that they could achieve both by adding a larger, less restrictive exhaust system to their vehicle. Not only do new exhaust systems provide increased power, they can also generate that sound that many automotive enthusiasts like to hear from their vehicle.

It is important to note that many of the newer cars are coming from the factory with highly tuned exhaust systems. Therefore, on some newer cars, an aftermarket exhaust might actually result in a minor loss in horsepower. The main things you need to do are learn the dimensions of your current system and compare that to the dimensions of the aftermarket system. For example, if you currently have a 1.5-inch system, and you want to upgrade to a 2-inch system, you will need to ask yourself if this modification will result in added power or will it actually decrease the power your vehicle is producing?

In the past, cars were built without a lot of consideration given to the exhaust system. The system was simply built to fit the car, dependent upon the amount of space available left over for the system. This resulted in some pretty wild kinks and twists that were made in the exhaust system. These excessive kinks, turns, and bends resulted in the exhaust gasses running into extra roadblocks on their way out the system.

The exhaust system is actually comprised of many individual pieces. Most commonly, the gases will leave the cylinder head and enter the exhaust manifold or the header (depending on which part your vehicle is equipped). The gases will travel through a small section of pipe, after which they travel through the oxygen sensor (O2 sensor) before finding their way to the catalytic converter. The catalytic converter is where the gases are converted from harmful poisons into water and oxygen.

After the water and oxygen exits the catalytic converter, it travels through more pipe leading to the muffler. The purpose of the muffler is of course to muffle the sound of the exhaust as it leaves the vehicle. Without a muffler, the vehicle would be extremely loud, so much so that you can hear the operational motor from more than a block away. After the muffler is another small section of pipe leading to the rear of the car, where the exhaust fumes are discharged.

As you can see, there are many components that come into play when trying to modify your exhaust system. Replacing one exhaust system component and not the others can make the process of trying to increase power to your vehicle a futile endeavor.

Many stock exhaust systems are not 'mandrel bent', but aftermarket exhaust systems are made with a mandrel bent. Mandrel bending is when a set of balls, called a mandrel, is inserted into the pipe during the bending process. These balls are positioned and pulled through the pipe so that the bends are not deformed and maintain a close-to-perfect shape throughout the length of the bend. OEM exhaust systems today are most often 'CNC bent', which is a process where a computer-controlled set of motors controls the position of the tube and the rotation of one bend in relation to another.

The main advantage of mandrel bending is that the full-length of the tubing or pipe is the same diameter throughout, instead of having a smaller diameter of pipe at locations where the pipe is bent. Many have suggested that the best aftermarket exhaust systems utilize a combination process called CNC mandrel bending.

If you understand the concept that a cars engine is basically a big vacuum cleaner that takes air in and pushes air out, then you will be able to understand the importance of the exhaust system for the overall performance of your vehicle. If you cannot get the gases out of the engine quickly, then you cannot take in clean fresh air quickly either. If you watch professional drag racing on television, you will see that the cars typically only have headers and no other exhaust. The reason for this is that there are fewer restrictions on the gases as they exit the engine. Of course, this is for professional race drivers and would not be practical or legal for street-driven vehicles.

If you can, imagine what the stock Chevrolet exhaust system looks like. The Chevrolet parts are probably a very narrow diameter with many restrictions in the stock Chevrolet mufflers, pipes and other exhaust system components. With a little bit of imagination, anyone could see how one might easily improve his or her Chevrolet vehicle's performance with a higher flowing exhaust system.

In addition to the performance value, a new system can also give you that throaty sound that car enthusiasts yearn to hear in their modified vehicles. You know the sound; you hear it at car shows or when cars with aftermarket systems pass you on the road. You hear them coming and think to yourself, well this person means business and they really do have some extra power under their hood.

Overall, a new exhaust system will give you a good return of power on the amount for the amount of money spent, depending of course on your specific vehicle. A quality exhaust system will also compliment any future engine modifications that you intend to make, since more power in the engine means more gases are being pushed out of the exhaust.

If you intend on overhauling your vehicle's exhaust system, make sure that you do it right. Given the complexity of today's vehicle exhaust systems; cutting corners may be more expensive than doing the job right the first time.