Twin Exhaust Buying Guide

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Twin Exhaust Buying Guide

Upgrading an exhaust system is a great method for improving engine flow in a vehicle. One exhaust solution that many car lovers leverage to enhance their vehicles is a twin exhaust system, sometimes referred to as a dual exhaust system. For a consumer who has never explored an exhaust upgrade for a vehicle before, it can be beneficial to take some time to learn a bit about twin exhausts, including how they work and the various types that are available on the market today.

Consumers can also benefit from exploring their retail options. While traditional, brick-and-mortar vendors can offer a modest range of choices when it comes to twin exhausts, an online aggregator like eBay can often provide a much more diverse selection.

How Exhaust Systems Work

Before jumping into the consumer choices that are available in dual exhaust systems, consumers should first review some of the basics of an exhaust system and how it functions. The exhaust system is a critical final step in the operation of a combustion engine. Combustion engines work by first sucking oxygen and fuel into the cylinders of the engines. A spark plug ignites this mix, creating a mini explosion inside the cylinders. It is this explosion that forms the 'combustion' of a combustion engine. This explosion provides the raw energy an engine needs to propel a car's systems. However, it also creates waste gases that can potentially choke and stall an engine. In order for a combustion engine to operate efficiently, it needs to evacuate these gases through an exhaust system. The more efficiently and quickly an exhaust system performs this function, the better an engine can perform.

Upgrading to a Twin Exhaust

When a consumer buys a vehicle, it is fitted with a basic, factory-standard exhaust package. These systems typically deliver the bare minimum in terms of exhaust efficiency, expelling gases well enough to keep a vehicle healthy, but not increasing performance in any way. These OEM systems tend to have pipes with smaller diameters, tighter bends and baffles, and limited flow. Upgrading to a dual exhaust system provides a much more efficient and rapid method for expelling exhaust gases from an engine. A dual exhaust typically uses two mufflers and two tail pipes to expel gas.

Parts in a Twin Exhaust System

Consumers should familiarise themselves with the various parts in various exhaust systems. Understanding this terminology can make the purchasing process much simpler.

Exhaust Part


Exhaust Manifold

Attaches to engine block

First release point of gases from engine

Catalytic Converter

Cleans exhaust gases of harmful emissions

Installs after the manifold in a system


The 'silencer' on an exhaust system

Controls the noise level of the exhaust


Last point in a system

Releases exhaust gases into the atmosphere

Various twin exhaust upgrades start at different points along this basic chain of parts. Knowing these essentials can help consumers understand the differences between options like cat-back and header back systems.

Types of Twin Exhaust Systems

There is a range of twin exhaust systems from which consumers can choose. These choices deliver a wide range of performance enhancements and price points. By learning about these options, consumers can make informed decisions based on their performance needs and budgets.

Header Back Twin Exhaust Systems

A header back system is what some may refer to as a 'true' dual exhaust system. This system, sometimes referred to as a manifold twin exhaust, keeps the two banks of an engine separate throughout the entire exhaust process. The exception to this is when a manifold twin exhaust might use an equalisation tube to connect the two banks at one point. The term 'header back' refers to the fact that everything in an exhaust system from 'the header on back' is addressed by one of these systems.

Axle-Back and Cat-Back Twin Exhaust Systems

There are also twin exhaust systems that do not divide into two separate exhaust channels until later on in the systems. These options do not deliver as much performance enhancement to vehicles as true twin exhaust systems, but they do enhance performance significantly over factory-standard systems. They are also often much more cost-efficient choices that can be easier to install, as well. Any installation a consumer undertakes should only be executed with the right guidance and knowledge. Just as replacing a car's audio system incorrectly can lead to electrical complications, replacing an exhaust system incorrectly can lead to a car not meeting with pollutant and efficiency standards.

Axle-Back Twin Exhaust Systems

An axle-back exhaust system addresses the muffler, tail pipe, over-axle pipe, and exhaust tips of a system, running from the rear axle back to the final release point. These are typically the most cost-effective types of upgrades to exhaust systems. They deliver a minimum of enhancement in comparison to other dual exhaust approaches.

Cat-Back Twin Exhaust Systems

Cat-back twin exhaust systems build upon axle-back twin exhausts by introducing the midpipe as part of the system, as well. The addition of the midpipe into this exhaust upgrade makes significant improvements to the horsepower of an engine and can also help with fuel efficiency. These options are usually more expensive than axle-backs, but they are still a more cost-effective choice than a full dual exhaust system.

Considering the Materials in Twin Exhaust Systems

In addition to considering the different types, consumers may also want to consider the materials used in twin exhaust systems. Different materials can deliver different performance benefits and affect the final prices of the systems, as well.

Aluminised Steel

Aluminised steel is an affordable material that is widely used in exhaust systems. The core of parts made with this material is steel, while the exterior is coated in an alloy of aluminium and silicon. This combination makes these parts resistant to heat and corrosion.

T304 Stainless Steel

T304 stainless steel is another popular choice when it comes to twin exhaust systems. It is also resistant to corrosion and does not harden and become brittle when exposed to extreme heat. It works well in a wide range of climates, making it one of the more diverse choices. 

T409 Stainless Steel

T409 stainless steel is steel that has been alloyed with titanium. This material is by far one of the most corrosion-resistant materials used in twin exhaust systems. It can come at a higher price point, but it can deliver an extremely reliable and resilient twin exhaust system.

Buying Twin Exhaust Systems on eBay

eBay offers a wide range of twin exhausts from which consumers can choose. Shopping on this site is easy, thanks to the search bar located on every page on the site, as well as eBay Deals pages for automotive parts. This search interface allows you to quickly search through eBay's countless listings to find the twin exhaust you want. Use a term that describe the system you want or run a search with a general term such as 'dual exhaust' to see all of the options that are available to you.

Evaluating Sellers on eBay

Consumers may also want to take a moment to evaluate the sellers on eBay. Doing this delivers the same benefits as evaluating the product itself. It helps you determine whether or not you are going to get the right solution to your needs. Just click on a seller's highlighted name and visit the seller's page to read feedback posted by other consumers and review past listings the seller may have posted.


For consumers who want to improve the performance and fuel efficiency of their cars, upgrading from a factory-standard exhaust system to a twin exhaust can be just the answer they need. These efficient exhaust systems provide a much faster way for engines to expel gases that can slow down engine performance. Dual exhausts come in many different versions with different designs and materials. If consumers take the time to learn about these variations, including axle-back, cat-back, and 'true' dual exhaust systems, then they can be ready to tackle the purchasing process at an online site like eBay or through a local automotive parts vendor. Either way, a twin exhaust system could be the perfect solution to add enhanced performance, efficiency, and responsiveness to a car.

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