Mike Lishego wrote:
>
> >BTW, urban myth rebuttal: Higher octane fuel does not give an
> engine more
> >power. Octane is the ability of the fuel to resist pinging, or
> >'pre-detonation.' You can get more power from higher compression.
> However
> >this higher compression will increase the affinity for pinging.
> Thus, the
> >need for higher octane fuel in your big-hp motor.
>
> You're right about high-octane fuel not giving more power under
> normal circumstances. However, since higher octane fuel resists
> pinging, the timing can be advanced to gain additional power.
Well, advancing the timing can give extra power under
some circumstances, but not always. It isn't a situation
where you can keep advancing the timing and keep upping
the hp. Eventually you just get more heat, rough running,
and other nasties.
Depending on the compression ratio of your car, the better
fuel might be helpful, or wasteful.
In my situation, my 1970 MGB runs fine on cheap stuff, my
Celica runs on cheap stuff, but I run my 75 Midget on
premium. If I don't, it can occasionally ping and will run
on after hot shutdown.
--
Trevor Boicey, P. Eng.
Ottawa, Canada, tboicey@brit.ca
ICQ #17432933 http://www.brit.ca/~tboicey/
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