RE: [ST] Octane

["Bob Floyd" <monobldg@xxxxxxxxxxx>]

Brett,

You used the phrase "bigger bang" in your reply. Ironically, that is in fact
precisely what you DON'T want, and the biggest potential problem with using
LOW octane fuel. As Matt pointed out in his reply, gasoline doesn't need any
spark at all to ignite. The heat of compression alone will set it off.
However, when that happens, its an explosion and not a clean burn. And as
Matt also pointed out, if that happens before top dead center (which is
usually the case), it actually tries to force the piston backwards in its
stroke which results in the infamous knocking/pinging/pre-ignition/whatever,
not to mention the obvious loss of power and less than complete burn. Put
another way, low octane fuel is sometimes TOO HOT, if you will, to be
effective and efficient. IF you have knocking/pinging/pre-ignition/whatever,
its BAD, VERY BAD and you may actually need to run higher octane fuel.

But my whole point at the start of this thread, was that if you DON'T
experience the dreaded knocking/pinging/pre-ignition/whatever, (never mind
the scientific formulas here) it can not only be just as bad for your
engine, it also costs you more in the process. Its just wrong to think of
high octane fuel as being better. Just because the oil companies call it
"Premium", that don't make it so. Higher octane fuels are specifically
designed to have a higher/hotter ignition point so they don't ignite too
soon. As several level headed responders pointed out, if you want maximum
performance and the cleanest burn, you should use the LOWEST octane rated
fuel you can, without experiencing knocking/pinging/pre-ignition/whatever.
To use a higher octane rating than necessary also leads to some of the same
end results as using one that is too low, namely unnecessary build-up of
deposits inside and higher emissions outside.

And an aside too Mr. Doo: I am riding!! I only do this when I'm supposed to
be WORKING!!

Bob
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