There are numerous benefits of a high-flow, catalytic converter-back exhaust system. Foremost, an aftermarket cat-back exhaust increases both the horsepower and fuel efficiency of your engine. Additionally, aftermarket cat-back systems offer an aggressive engine sound and styling improvements when compared to stock exhausts. To understand these performance benefits, it is helpful to know the function that the exhaust system plays in the engine combustion cycle.
Automobile engines generate power through a process known as internal combustion. The combustion cycle begins with the intake of air. The air is then mixed with fuel and compressed by the piston, whereupon spark plugs ignite the mixture, which drives the crankshaft and generates power. The pistons then expel the leftover gasses from the combustion cycle out of the exhaust valves. From there, the exhaust gasses flow through the exhaust system, from where they are eventually expelled into the atmosphere.
To maximize power and efficiency, exhaust systems are volumetrically tuned to create optimal exhaust flow in relation to the engine design. Both the piping design and diameter are chosen based off of the flow characteristics generated by the engine's combustion cycle. The exhaust system must allow exhaust gasses to pass freely through the piping while providing the optimal amount back pressure against the exhaust flow. This helps ensure the most efficient combustion cycle possible for a given engine.
Stock exhaust systems are designed with an emphasis on comfort and practicality. They are designed to generate back pressure, to reduce exhaust noise and emissions. In contrast, a performance cat-back system is designed to maximize engine efficiency. By utilizing larger piping and high-flow mufflers, a performance cat-back exhaust reduces back pressure and thus improves horsepower. Furthermore, since the engine is able to more easily expel exhaust gasses through the larger piping, a performance cat-back exhaust slightly improves fuel efficiency.
In addition to the performance benefits, aftermarket cat-back exhaust systems offer a customized vehicle sound and appearance. The reduction of back pressure and muffling effects allows your engine to generate a louder, more aggressive sound as compared to the stock unit. Most aftermarket cat-back systems also feature decorative touches, like chrome tips. This gives the rear of your vehicle a customized look. Finally, many aftermarket cat-back exhausts feature a much lighter construction than stock systems. The reduction in vehicle weight allows for a very slight improvement in acceleration and braking performance, as well as fuel economy.
