Charlie Springer wrote:
On Sat, 24 Sep 2005 23:45:43 -0700, Roger wrote
(in article ):

Alcohol which has a low octane rating although it keeps getting credit
for a high one, when added to gas up to 10% by volume will increase
the octane rating of the fuel. 10% seems to be the maximum amount for
increasing the octane rating.

Can you explain the octane rating? In my little world octane is a chain of 8
carbons with 18 hydrogens hooked on.


Memory fades but the standard test for octane rating goes something
like this:

A standard engine is set up and run on the fuel to be tested. Than
a standard additive (hmm, pure octane perhaps?) is added to the fuel
until the engine begins to kock. The more of that additive it takes
to make the engine knock, the higher the octane rating.

The rating posted on gas pumpps in the US is the average of a
bench test and a test on an engine installed in a vehicle.

Or something like that.

Octane rating is an indicator of the fuel's resistance to
predetonation (knocking). It is not an indicator of how good
the fuel is in other repsects.

--

FF