Do I really need… part 15 – Aftermarket Exhaust System

The 4WD aftermarket exhaust system market has blown up in the past couple of years. Everyone seems to want the latest, greatest and biggest exhaust that they can fit underneath their rig. But is the expense worth the gains?

The belief that a 3” exhaust will make your car perform better because that’s what everyone else has got is almost universally wrong – especially on smaller (2.5 – 3l) engines. They may sound better (or just different) depending on what you do with mufflers but unless you’ve done a custom flash tune or upgraded your engine internals, injectors and turbo a bigger exhaust won’t give you much better power by itself. A good exhaust will help with turbo lag and pulling power, but you just don’t get massive kilowatt gains without extra engine work.

An exhaust system is fitted to remove the waste gasses from your engine, so in theory it makes sens that with a bigger pipe, the gases can escape quicker. This belief comes from thinking that a bigger pipe is need to reduce back pressure, but what’s really needed is to minimise the restrictions on the gas flow, allowing the exhaust gases to flow easier.