Exhaust/compression Qu

[Toby]

Does anyone know what would happen to an engine if you were to drive without the exhaust on i.e downpipe onwards.Or if there was a huge hole etc... Im sure this would effect the compression but can anyone clarify this.

Thanks everyone toby

[VTRick]

compression has noithng to do eith the exaust. your getting confused with back pressure.

and to answer your question, no, it wouldnt make too much difference to a turbo car. only thing youd loose is a bit of low down torque. probably more power up top to be honest. an NA car would run like a bag of sh*t though without any back pressure.

why do you want to do this anyway, you got a wepr system doncha?

[nrgizerbunny]

compression would be the same it is determined by crank geometry, the only difference would be the exhaust valve/intake valve would be tuned for a particular back pressure. result would be a substantial amount of fresh air/fuel going out the exhaust - hence lack of power.

it would have some affect on turbo performance. if you reduce the pressure on the "low pressure" side of the turbine the turbine would spin faster and give you more boost (unless the wastegate kicked in). so you would get more power in my opinion but this is offset against the valve problem described in paragraph 1, but i don't suppose you would no until you actually tried it.