Headers, specifically exhaust headers, are a popular bolt-on modification in the automotive world, known for their ability to boost engine performance. Essentially, car headers are designed to optimize the expulsion of exhaust gases from your engine’s cylinders, making the engine work more efficiently.
Edelbrock exhaust header wrapped for Chevrolet engine
The Role of Headers in Engine Performance
To understand how headers improve performance, it’s crucial to grasp the basics of a four-stroke engine cycle. An engine generates power during the power stroke when fuel combusts and expands within the cylinder. However, this power-generating stroke is supported by three other strokes: intake, compression, and exhaust. These supporting strokes can consume engine power, reducing overall efficiency.
Back Pressure: An Engine Performance Bottleneck
One significant way an engine can lose power is through back pressure during the exhaust stroke. In this stroke, the exhaust valve opens, and the piston pushes the burnt gases out of the cylinder. Any resistance encountered by the piston in expelling these gases is considered back pressure and wastes engine power. Employing multiple exhaust valves, rather than a single one, is a common strategy to improve exhaust flow by creating a larger exit path.
Exhaust Manifolds: The Standard System
In most stock vehicles, exhaust gases, after leaving the cylinders, enter the exhaust manifold. Typically, in engines with multiple cylinders like four- or eight-cylinder configurations, several cylinders share a single manifold. From the manifold, the exhaust gases are channeled into a single pipe, moving towards the catalytic converter and muffler.
However, the manifold design can be a significant source of back pressure. Exhaust gases from different cylinders can create pressure build-up within the manifold, negatively impacting the subsequent cylinders that utilize the same manifold. This pressure interference hinders efficient exhaust flow and reduces engine performance.
How Exhaust Headers Eliminate Back Pressure
Exhaust headers are engineered to overcome the back pressure issues inherent in exhaust manifolds. Instead of a shared manifold, each engine cylinder is allocated its own dedicated exhaust pipe. These individual pipes then converge into a larger pipe known as the collector.
A key design feature of headers is that these individual pipes are meticulously crafted to be of equal length. This equal length design ensures that exhaust pulses from each cylinder arrive at the collector at evenly spaced intervals. This synchronized arrival minimizes pressure interference and effectively eliminates back pressure caused by cylinders sharing a common manifold, thus enhancing engine performance.
Exhaust Headers: Frequently Asked Questions
How much does exhaust manifold replacement cost?
According to Repair Pal estimates, replacing an exhaust manifold can range from $1,180 to $1,284. This highlights the potential cost implications when considering upgrading or repairing exhaust systems.
Do exhaust headers really increase horsepower?
Yes, exhaust headers are indeed a recognized method to enhance engine performance. They are considered a readily installable upgrade that can effectively improve horsepower by optimizing exhaust gas flow.
What is the primary function of exhaust headers?
The main objective of exhaust headers is to facilitate the engine’s task of expelling exhaust gases from the cylinders. By reducing back pressure, headers enable the engine to operate more efficiently.
What is the role of an exhaust manifold?
An exhaust manifold serves as the initial collection point for exhaust gases exiting the engine cylinders. From the manifold, these gases are directed into the subsequent components of the exhaust system for further processing and expulsion.
How does an exhaust manifold affect engine performance?
Exhaust manifolds can impede engine performance due to back pressure. The design of manifolds can lead to pressure accumulation from exhaust gases, which then restricts the efficient expulsion of gases from other cylinders, ultimately reducing engine power.
