Exhaust Systems: Explaining the Purpose of Each Part

Many Holden VE owners who are looking to improve their vehicle’s performance know that the best way to do so is to replace their stock exhaust with an aftermarket one. The main reason for that is because stock exhausts are restrictive and rob your Holden out of potential power. In order to get a better idea of why that is and how an aftermarket performance exhaust improves performance, you need to understand how each and every exhaust part works.

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Exhaust Manifolds

The first exhaust part to handle the exhaust gases from your engine is the manifolds. The manifolds are bolted onto the cylinder heads and they retrieve the gas from the engine’s combustion chambers. Aftermarket Holden VE extractors are the performance alternative to stock manifolds. Aftermarket Holden VE extractors are mandrel-bent, which allows exhaust gases to flow freely from the engine. This not only reduces backpressure which can rob you of power, but it also helps build up exhaust flow velocity that creates pulses which scavenge the gases from the engine.

Catalytic Converter

The catalytic converter is responsible for transforming the toxic emissions that come out the engine into less toxic gases before the exhaust system releases them into the atmosphere. Catalytic converters operate in a pretty simple manner – gases flow through two ceramic honeycombs located in the catalytic converter, both of which are coated with precious metals. When the exhaust gases touch the coating, a chemical reaction ensues which converts the toxic emissions into carbon dioxide, oxygen, nitrogen, and water. Aftermarket catalytic converters are also known as high-flow cats, and they basically do the same thing, except they’re more efficient.

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The muffler is one of the most recognizable parts of exhaust systems. It’s responsible for reducing the exhaust noise, and while that sounds like a pretty straightforward task, different models do it differently. Depending on the style of the muffler, it can use a combination of chambers, baffles and perforated tubes to muffle the sound. Stock mufflers create backpressure, whereas aftermarket ones don’t. Further, aftermarket mufflers aren’t always made to muffle your exhaust sound, but instead, they can make your car sound more aggressive.


All of the pipes, including the downpipes, crossover pipes and tailpipes connect all of the aforementioned exhaust parts together. Aftermarket exhaust pipes are wider in diameter, which basically means there’s more space for gasses to flow throughout the entire system. This goes both ways – more cold and clean air gets to your engine, while the emissions from the engine get out of the system faster as well.