TECH Q: How does 4-2-1 exhaust make big noise?

[bigairbox]

I have lots of knowledge of what many cars can do but not how they do it!!!

Im developing a serious interest in Caterhams..maybe you guys could help me with this Q...

Does this exhaust make standing waves or whatever theyre called?

cheers

[Avocet]

I think both 4-2-1 and 4-1 exhausts make standing waves - any good exhaust should. The difference will be the engine speed / throttle opening at which it all starts happening "in-phase" so that the low pressure area behind a spent charge leaving one cylinder passes the end of one of the other headers just as its cylider is about to release a charge of spent gas. This helps "suck" the gas out of the next cylinder and so on. I'm not sure if it makes any real difference to the volume of sound - that's more to do with the silencers but it might affect the quality of the sound.

[dino ferrana]

Bigairbox for such specific questions I would recommend www.blatchat.com as there are far more Caterham entusiasts on there.