The Anatomy of an Exhaust System

Injen SES exhaust system civic type R

Save The exhaust system is responsible for more than changing your vehicle’s pitch – it helps ensure optimum performance across a variety of surfaces. No matter the medium – from the dirt track to the strip to the street – the system can be tailored to match the application.

Combustion, of course, begins in the engine cylinders, with the spent gases leaving via the exhaust manifold, eventually exiting out the back or side of the vehicle. But knowing what the system was designed for is a far cry from knowing how each individual component achieves those gains for you. Read on, and get back on the road with greater knowledge of the whole.




Exhaust manifolds, like headers, have been described as the “starting blocks for your exhaust flow.” The manifold installs directly over the cylinders onto your engine head (pictured), each cylinder with its very own pipe. The pipes conjoin to form a single exit point, which connects to the head pipe (more on that below). The amount of exhaust manifolds you have actually varies according to engine size. V8s and V6s have two because there are cylinders on either side of the engine.




Headers, on the other hand, are aftermarket replacements for cast-iron exhaust manifolds. They have been mandrel-bent to enhance flow, and are typically custom-finished for heat-reduction in the engine bay.





Head pipes – also known as “downpipes” – make up the first section of piping and connect your exhaust header to the mufflers. Coated both inside and out to improve exhaust flow and bring down ambient heat, they’re typically manufactured without many bends, which makes for a clean, straight run to the muffler, but between the two you’ll find what is known as the catalytic converter.




Your cat converter is meant to keep harmful emissions – like hydrocarbons, carbon monoxide and nitrogen oxides – to a minimum. To do so, it has been filled with a ceramic honeycomb or beaded design, coated in platinum and palladium, which sparks a chemical reaction when they come in contact with any of the abovenamed pollutants. The converter transforms them into carbon dioxide, nitrogen, oxygen or water vapor. The threat has thus been neutralized.




The muffler is intended for engine noise reduction, which it does by channeling the flow of spent gases through a series of chambers. These chambers bottle the sound waves, forcing them into contact with each other until they eventually cancel each other out. Dual exhaust systems are equipped with two mufflers, one per exhaust manifold, but certain “false” dual exhausts only have the appearance of a two-muffler setup because of a backside splitter that converts a single head pipe into dual-exiting tailpipes.




Tailpipes, contrary to what their name would imply, don’t just exit out the back of your ride, but occasionally to the side. They typically have the most bends because they have to curve up and over the rear axle. Custom-finished or chromed exhaust tips can be fitted to the pipe to give your setup a look of its own (pictured). Tailpipes also come in a wide variety of shapes, including round, square and oval.

So, whether you’re after serious horsepower and torque gains, a distinctive growl or enhanced fuel economy, the reasons to take care when investing in a new exhaust system should matter a great deal more to you, now that you know what each part is designed for. Check out our wide selection of exhaust system upgrades today – and breathe a lot easier.


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