No doubt engine noise is caused by lots of factors. You can modify they exhaust to make it louder or quieter. I understand a lot of bikers modify their exhaust to make it louder.

As I understand it, there is a legal limit on noise emissions some for vehicles. To get round this bikes are supplied with a quiet exhaust and a second loud exhaust. They tell customers the loud exhaust is for use on private race tracks but obviously this is widely ignored.

We have been able to make very quiet engines for decades, noisy ones only exist to please people who need to feel the power of their car

I'd bet these sort of people derive their pleasure almost exclusively by knowingly annoying others. Power and speed are just bonuses. The main thing is annoying everyone else.

He’s not talking about engine noise. He’s talking about illegally modified exhaust mufflers etc. that are much louder than they should be.

You missed the point.

You can call out hooliganism or whatever the bad behavior is without making ridiculous claims about how engine noise is somehow illegal. That not only detracts from the point, it makes the poster look sort of ridiculous.

There are legal standards for both vehicle noise and vehicle emissions, at least in the UK. When owners modify their exhaust to make them noisier, they are likely breaching one or both standards. It is specifically illegal. https://www.gov.uk/noise-pollution-road-train-plane#:~:text=....

People like you are the real destroyers of communities. You're doing nothing against the guidelines, but arguing "just because" and trolling. Your comments have added nothing of value to the discussion.

why would fuel injection cause noise?

Sure but weren't mufflers invented specifically to address this? I think the OP is trying to talk about people who modify or remove mufflers in order to actively make their car louder.

Pretty much every car for the last thirty years has had fuel injection, but most of them aren't very loud.