healeys
[Top] [All Lists]

compression Ratios

To: 'Healeys' <healeys@autox.team.net>
Subject: compression Ratios
From: PG <britishcars@shaw.ca>
Date: Wed, 14 Feb 2007 18:12:34 -0800
List,   hear is some food to dwell on:

 

I was reading some articles last evening and a question popped to mind.

 

Why is it that the Porsche 2007 911S has a compression ratio of 11:8 to 1
and yet does not have detonation whereas an older English motor with
compression of 10:5 to 1 has issues?

 

Is it that the advertised compression numbers are "static" compression and
because of valve timing, in particular, the closing of the inlet valve, that
the dynamic compression on the Porsche might be substantially less than the
11:8 to 1.

 

Also, could it be combustion chamber design, better cooling etc etc.

 

Any thoughts

 

Regards,

Paul




<Prev in Thread] Current Thread [Next in Thread>