Paul,
My guess would be a combination of combustion chamber design and
electronic controls. Basically the ignition is retarded at times when
the full induction charge would normally result in detonation i.e. full
throttle at low RPM and then is advanced when the induction efficiency
drops off.
Michael
In New Zealand
-----Original Message-----
From: owner-healeys@autox.team.net [mailto:owner-healeys@autox.team.net]
On Behalf Of PG
Sent: February 15, 2007 3:13 PM
To: 'Healeys'
Subject: compression Ratios
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
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