DANMAS@aol.com wrote:
>
> In a message dated 97-10-26 00:20:18 EDT, curry@wolfenet.com writes:
>
> > My experience is that on engines that have 8:1 or less compression,
> > regulat (87 octane) fuel seems to be ok. As the compression goes up,
> > however, octane requirement increases to the point where "pinging" will
> > occur.
>
> Joe:
>
> I think that is a good number for a rule of thumb. I had the head milled on
> mine, to bring the compression ratio up to somwhere between 9 and 9.5:1
> (unfortunately, after I had the head milled, I lost my calculations, and I
> don't remember the final number - DUH! Senility is not a pretty thing!) I've
> had no problem at all with 87 octane.
>
> Dan Masters,
> Alcoa, TN
>
Dan,
As with all rules of thumb, there are obvious exceptions. I try to
apply these pearls of wisdom within the safest parameters. Obviously
8:1 compression ratio is safe to say should work very well with 87
octane. If you apply the next rule of thumb "increase octane as needed
to eliminate pinging", the rule works. There is no formula for what
compression ratio relates to pinging in particular octane situations.
This is because there are more parameters involved than those mentioned.
I guess one could over analyze the situation, but when you hear the
pinging (after you are sure the engine is properly tuned) then it is
time to increase octane to solve the problem.
Now that we've beat the problem to death, lets move on to more
interesting topics.
Topics such as Spitfire doors.......
Joe Curry '63 Spitfire (thinking about Gull Wings)
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