exhaust design & placement on vehicles (1 vs 2, left / right / rear)

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How much is aesthetics & how much is functional consideration? Looking at cars on the way to work today got me wondering.

In: Engineering

A lot of it is just aesthetics

A large displacement engine (think 6L V8) might legitimately need two exhaust pipes to carry the volume of exhaust gasses without too much back pressure, but most modern cars don’t.

Most fancy exhaust tips you see on the back of modern production cars are solely for aesthetics. There has been a trend recently of showing cars having fancy dual exhaust ports on the back [but the exhaust actually just shoots at the ground instead](https://s1.cdn.autoevolution.com/images/news/fake-exhausts-invade-2018-paris-motor-show-and-mercedes-is-the-biggest-offender-129135_1.jpg). This lets you put matched fancy parts on the back that look nice and keep things symmetric but won’t get dirty from sooty exhaust going through them. Some cars have one real one and one fake one just to maintain the symmetry. [Here’s a nice collection of exhaust deceptions from 2018](https://www.autoevolution.com/news/fake-exhausts-invade-2018-paris-motor-show-and-mercedes-is-the-biggest-offender-129135.html#agal_0)

Left vs right for single exhaust is often down to where does everything fit in the engine bay and undercarriage. If forcing the exhaust to go on the left side means you need to tweak the transaxle transmission layout, you’re probably just going to route it on the right and be done with it.