"Chris Bacon" wrote in message
...
EricP wrote:
"Dave Plowman (News)" wrote:
In article EricP wrote:
I'm nearly convinced. Is there any negative side to running higher
octane fuel in your engine?

Yes, you could be wrecking your engine if the compression ratio can't
take the faster burning fuel.

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!

Correct.

"The stroke of the pistons"... do you mean the swept volume, or what?

Chris.
You're making a fool of yourself. Just listen to Dave Plowman (and others).

Where does volumetric efficiency come into this, do you think?

It's got nothing to do with the compression ratio. (I may stand corrected).


Volumetric efficiency is related to the amount of air that is able to enter
the combustion chamber during the induction stroke
(4 stroke engine). It's helped by using better cylinder head design and
construction (which includes better induction manifold design and
construction). It's also helped by valve timing "overlap", and probably by
improved exhaust system design.
_Amongst other things_.

I used to own a BSA Blue Star 350cc OHV _single_ cylinder 1934 motorcycle.
This bike had _twin_ exhaust ports and exhaust systems. The only reason for
this, in my opinion, must have been an improved volumetric efficiency ( the
single inlet and single exhaust cylinder head valves were the same size).

Sylvain.