In article ,
EricP wrote:
That is simply wrong. High octane pertol burns *more slowly* than low. You
won't damage any petrol engine by using a road fuel with a higher octane
rating than it actually requires. The only harm is to your wallet.

A look in the data section of the handbook should clarify it.

Perhaps you'd give a direct quote from one?

Sigh.

Dave it is all to do with the stroke of the pistons and size of
compression chamber. Believe me, it's factual!

Not in any of the many many technical publications on IC engines I've read
over the many many years. ;-)

The stroke of the piston and the size of the combustion chamber determine
the compression ratio. If you have too high a compression ratio for the
octane of fuel used you'll have to compromise the performance and economy
by retarding the ignition. This is to *prevent* the mixture exploding and
causing pinking. If the octane rating is higher than required, absolutely
nothing untoward occurs.

Basically you've got things the wrong way round. Too low an octane rating
can damage an engine. Not the other way round.

--
*Whatever kind of look you were going for, you missed.

Dave Plowman London SW
To e-mail, change noise into sound.