Why are some cars, like muscle cars, so much louder than others?

Question

Why are some cars, like muscle cars, so much louder than others?

In: Engineering

Answer 1

There are many things which can effect the noise output of a car. The main 4 are:

* Induction (Air Intake)

* Exhaust

* Engine Displacement (Capity of the combustion chambers, usually measured in Litres)

* Engine RPM (The speed of which an engine rotates.

To start with, Induction is how the air is getting into the engine. Some cars have different styles of air filter which are more open. These flow more air and can allow for better performance. This increased air flow can make the sucking noise of the engine louder. Lots of modern cars are also using what is called forced induction. This is where the engine uses a device to force pressureised air into the engine to increase combustion efficency and power. The two main ways or doing this are through Turbochargers and Superchargers.

Some exhausts are louder than others. This can be due to less sound dampening material in the silencers, or due to the car being fitted with a high flow performance exhaust. High flow exhausts as the name suggests; allow more air to escape the engine faster than a stock, restrictive exhaust. This has the oppertunity to increase engine power output at high RPMs.

Engine displacement is the physical capacity of the combustion chamebrs in the engine. For Example my car has a displacement of 1.4 Litres and has 4 cylinders, so each cylinder has a capacity of 0.35L. The bigger the displacement, generally, the bigger the bang is (as more air/fuel is able to be drawn in). The bigger the bang, the bigger the noise.

Engine RPM is how fast the engine is spinning (measured in rotations per minuite). If an engine is spinning at 9000RPM, it will create a lot more noise than an engine spinning at 850RPM. This is because there are more explosions happening per second.

This is super simplified but should be helpful