The emission of exhaust gases out of your engine is normally restricted by stock exhaust systems, preventing your engine from achieving its maximum power capacity.
The outlet manifolds or headers are, of course, the first combustion components to treat spent hot gas from your engine. The standard manifolds are tight, but mandrel-bent aftermarket headers can enable exhaust gas to pass easily from the engine, minimizing power-robbing internal pressure and enabling the exhaust system to eject gases much more effectively. A good collection of headers will actually increase the speed of the exhaust flow enough to generate energy pulses that extract or scavenge spent gases from the engine.
So, what exactly constitutes a good header for your system? Consider the following points:
Bigger Isn’t Always Better
The size of the primary, which are the pipes that link directly to the exhaust ports, is one of the most important factors to consider when selecting a set of headers. There are several considerations to consider when selecting the appropriate pipe length—engine size, horsepower, planned usage of the vehicle, and so on.
But one general problem is assuming that bigger is better. While smallerlength primaries flow less volume than larger primaries, a smaller length pipe provides a faster exhaust flow rate with just enough pressure to promote good low- and midrange torque.
As a result, most header manufacturers suggest moderate pipe diameters for street uses, such as 1 12 inches to 1 5/8-inch diameter primaries for a small block vehicle.
Shorty vs Full Length
Headers are available in a range of sizes and configurations for specialized applications, such as fender well, dragster, and circle track headers. We’ll stick to the most popular street performance designs: full-length, shorty, and mid-length.
Primary tubes on full-length headers are bigger than the mains on your existing exhaust manifold. Most of the time, these 4 primary tubes empty into a single collector pipe, creating a “4-1” configuration. Full-length headers contribute to more total power with decent power in the low- and mid-rpm ranges—exactly where most street-driven vehicles would benefit the most! The longer primaries also reduce the possibility of escaping gases being drawn back into the system.
Shorty headers are made up of 4 short primaries that feed into a single short collector pipe. Shorty headers are ideal for highly crowded engine chambers or reduced vehicles where clearance is an issue due to their small dimensions Shorty headers are also commonly compatible with the existing stock exhaust.
Mid-length headers share some of the advantages of full-length and short-length headers. They have longer primaries than the stock manifold, which helps to produce more low- and mid-range torque and strength. However, since the primaries are shorter than full-length headers, there is more clearance for lowered vehicles.
Stainless Steel vs Mild Steel
The majority of aftermarket turbo manifold is made of steel or stainless steel. The benefit of using a standard steel header is straightforward: cost. Mild steel headers are considerably less expensive than various forms of stainless steel, but they lack the toughness of stainless steel.
In extreme environments, such as the atmosphere in your engine compartment, stainless steel headers outlast mild steel headers. They are more resistant to intense heat and will not rust. Stainless steel’s superior thermal properties and rust-free surface allow it to sustain a smooth, restriction-free exhaust flow all over its lifetime.