What kind of gas

[Larry" <rocco16v@netzero.com (Larry)]

Kareem-
I see where your thought process is coming from, but, no, higher altitude
does not reduce compression ratio.  That is fixed.  What it will reduce is
cylinder pressures, which may then reduce the need for high-octane fuel.
You are thinking, though.....and that's good.

Larry  sandiego16V

>
> What about at higher altitudes...
> doesn't thinner air effectively reduce the engine's
> compression ratio?? Perhaps in those cases a lower
> octane number is justified in some higher compression engines.

> Kareem