O/T Compression ratio and supercharging

[Don.F.Broadus at ucm.com]

You are correct, The mechanical compression ratio can be 10:1 but when you
check it with a gauge the effective compression ratio
pressure will  be on par with a 9:1 engine. Mechanical compression gives you
efficiency while effective compression ratio that is controlled by valve
timing gives you knock control and good combustion.

> -----Original Message-----
> From:	Shannen Durphey [SMTP:shannen at grolen.com]
> Sent:	Wednesday, May 26, 1999 12:55 PM
> To:	diy_efi at efi332.eng.ohio-state.edu
> Subject:	Re: O/T Compression ratio and supercharging
> 
> Todd....!! wrote:
> 
> > Another tidbit that may or may not help is that my 91 Mitsu Eclipse
> > Turbo 5-speed had only 120 lbs. of compression pressure on all four
> > sylinders....
> > 
> I believe that cranking compression ratio has more relation to stroke
> length and valve timing than compression ratio.  Anyone?
> Shannen