If you are looking for power and performance from your vehicle, consider upgrading to new exhaust headers. In my opinion, replacing stock headers is for more beneficial than modifying your intake or muffler.
An exhaust header is an after market automotive part designed to improve vehicle performance. The small gain in performance facilitated by an exhaust header is important to high performance drivers who often make other modifications to their vehicles in order to increase speed. These modifications include the installation of larger intake vents for the engine. An exhaust header modifies the exhaust system to prevent back pressure, meaning that the cylinders do not have to work as hard to push exhaust out as they do in a traditional system. There are different types of exhaust headers depending on the needs of the drivers, with some tuned for low performance and others aimed at high performance on the open road.
In a conventional exhaust system, after the cylinders combust, they push the exhaust out into the exhaust manifold, which routes the exhaust out of the vehicle through the exhaust pipe. However, the exhaust manifold can create a back pressure which pushes against the cylinder, meaning that it has to exert more energy to push the exhaust out and prepare for the next firing. As a result, some efficiency can be lost.
An exhaust header works differently, essentially creating a miniature exhaust pipe for each cylinder and routing the exhaust to a centralized collector which is much larger. The pipes of an exhaust header are bent to fit under the hood and cut to the same length so that the exhaust gases will arrive sequentially in the collector as each cylinder fires. This eliminates the back pressure problem and allows the cylinders to operate more effectively.
Aftermarket headers can be bolted in place of the stock cast-iron headers. Small block headers usually use 1-5/8-inch primary tubes and big-block headers use 1-3/4-inch tubes. An important consideration when choosing headers is quality of materials. Header tubing vary in thickness, but a good quality header should use between 18-gauge and 14-gauge tubing. The metal used in the header is also important. Some headers are mild-steel, which will rust and corrode over time. Headers can be coated, either with a ceramic coating or a high-temperature paint. Using 100% stainless steel construction eliminates the need for coatings, but it is usually out many buyer's budgets. When headers are shipped, they sometimes come painted. Be aware that this coating is only for rust prevention during shipping, and the paint will not hold up to the heat once the header is installed. When headers are added along with a cat-back exhaust and high-flow catalytic converter, you can usually gain 20-30 horsepower over stock.
In some cases, an exhaust header can be tuned to pull at the exhaust valve of the next cylinder and suck the exhaust out, meaning even less work for the cylinder. Drivers who desire more power for around town driving and better acceleration under a heavy load usually opt for a low performance exhaust header, while drivers who are looking for speed on the open road prefer high performance headers.
A variety of manufacturers make exhaust headers for a dizzying assortment of vehicles, and it is important to install the exhaust header designed for your car. Because exhaust leaks can be dangerous, the exhaust header should be installed with care, or professionally if there is any uncertainty. An improperly installed header could lead to an exhaust leak which vents into the cabin of the vehicle, causing symptoms of carbon monoxide poisoning in the driver and passengers.
