James you are correct. The higher the octane content the slower the fuel
burn (spread of the flame front across the cylinder) thus resulting in a
smoother power stroke as opposed to a sudden (relative) explosion (knock).
Just remember that we are talking micro seconds here, nothing you can
measure. But you sure can hear that knocking when you buy the cheep stuff!
Hugh
----- Original Message -----
From: "Max Heim" <mvheim@attbi.com>
To: "MG List" <mgs@autox.team.net>
Sent: Thursday, April 10, 2003 4:52 PM
Subject: Re: mixture and octane
> AFAIK it has nothing to do with mixture, just timing. It's not like the
> total energy contained in premium fuel is greater, it just has better
> anti-knock qualities (which I think has to do with flame spread, but I may
> be talking through my hat).
>
> on 4/10/03 4:43 PM, James Nazarian at jhn3@uakron.edu wrote:
>
> > List, I'm looking for a little experience to weigh in on something here.
> > I'm curious, given a particular car and driving conditions, will higher
> > octane gas allow you to lean out the mixture? or does it just allow you
to
> > advance timing? I'm not looking for any particular advice here, just
> > curious about how octane rating and mixture interact.
> >
> > James Nazarian
> > 71 MGB Tourer
> > 71 MGBGT V8
> > 85 Dodge Ram
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