how does high compression work?

[jammygit]

i know its a hot friday afternoon but here's a techy question.
how does a HC engine differ from non-HC - does it have a larger cylinder displacement? (although i would have thought that would be a larger engine).

i presume it is something to do with the compression cycle - is it the lenghts of the piston rods??

obviously you can see i have no idea. would love an explanation (with diagrams)

[GreenV8S]

quote:i know its a hot friday afternoon but here's a techy question.
how does a HC engine differ from non-HC - does it have a larger cylinder displacement? (although i would have thought that would be a larger engine).

i presume it is something to do with the compression cycle - is it the lenghts of the piston rods??

obviously you can see i have no idea. would love an explanation (with diagrams)

The HC TVR engines I've come across are Highlift Cam not High Compression. High Compression normally means that the swept volume (piston area times stroke) remains the same and the volume in the head/piston at the top of the stroke is reduced. Raising the compression ratio means the charge burns faster, which increases the potential power output.

[2 Sheds]

Some 4.0L engines run smaller volume heads ( high compression ) but as the pistons are pocketed ( to avoid valves hitting pistons)normally associated with high lift cams, the compression ratio stays much the same .