"92, 95 and a 97 Octane rating. The higher the Octane, the more combustible the fuel.". Sorry but the opposite is true.. That 'cackle' you hear from a diesel engine is in fact the sound of the fuel detonating... that's why pistons etc in diesels are a lot thinker so they can deal with that. Diesels rely on the 'flash point' of the diesel to ignite... with a petrol engine, this does happen and it's a really bad thing (pinking/knocking) one of the easiest ways and usually the first thing done to get more power from a petrol engine it to skim the block/head to up the compression, however this can have a detrimental effect because LOW octane has a LOWER flash point.. or, it will detonate at a lower temps/compression and you'll get knocking/pinking. basically, high octane fuel will burn slower and detonate less readily under the same temps and pressure/compression as low octane. you can run a standard engine (relatively low compression) on low and high octane fuel, but I wouldn't recommend running high compression engines on low octane as it will most likely detonate/knock and cause damage... in fact it I suspect that with modern cars where the advance and retarding and fuel ratios are constantly adjusted you'd find less mileage running the latter on low octane as I would suspect the increase in temps will cause the ECU to increase mixture and r e t a r d the timing in order to save the valve (exhaust in particular) and the cat. Now, with diesel the opposite is true.
