I was once a chemist but now that I have changed careers, a lot of that old
knowledge has become a bit murkier. But when it comes to higher elevations,
the changes in air density effects both fuel mixture and octane
requirements. And that will effect your fuel mixture settings as well as
timing. It would seem logical too that the pinging would occur at lower
elevations as the octane requirements will increase. As James likely has
observed, the octane ratings for supreme gasoline are much higher in Ohio
than in Colorado. I'm not positive what they sold in Boulder but high
octane gas in the higher reaches of the Rockies is likely something like
89. Here in Billings which is only 3500-4000 feet, gas is usually sold in
85-87-89 octane ratings. I'm not sure if you can even find it in the low
90s (I could be wrong though). But the point remains though that lower
octane fuel works fine for higher elevations.
David
At 10:47 AM 4/13/2003 -0500, Charles & Peggy Robinson wrote:
> Hmmm, I wonder if the pinging is because of differences in the
>gasolines.
>
> CR
>
>James Nazarian wrote:
> > I have a question of actual application this time. This is what got me
> > thinking about the octane stuff I sent earlier. Last fall I moved from
> > Boulder Co ~1mi above sea level, to Medina, Oh ~1000 feet above sea
>level.
> > I did the obvious mixture changes and readjusted idle etc, but found
>that I
> > had to retard the timing a couple of degrees to prevent pinging under
>load.
> > Does this make sense? Should I have to run less advance near sea level?
> >
> > James Nazarian
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