Thread: Octane?
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Old 08-14-2004, 08:21 PM
nglitz's Avatar
nglitz nglitz is offline
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Join Date: Aug 2004
Location: Hamilton Square NJ, near Trenton
Posts: 391
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MTI and Q have hit it on the head. Duke 2.6, too. Octane rating is only an anti-knock rating.

Nothing else.

Not power, not cleanliness, not "quality", not goodness, not premiumness, not "more $ is better" ness, not sex appeal. There is no "insurance" to be gained by spending that 2 or 3 dollars more. It is not "better" for your car, unless the lower octane fuel knocks.

If anything, higher octane fuel will burn dirtier than regular. That higher octane is achieved with additives. The additives are used to slow down the burning rate of the fuel/air mixture. Tetraethyl lead used to be the additive of choice but we know where that went. The current additives still slow down the burn rate but leave behing traces of themselves. As buildups of crud on sparkplug electrodes and valve faces. Neither is a good spot for unwanted deposits.

Edited to say that I stumbled across an illustration of excessive fuel additive causing a buildup on sparkplug electrodes. Serendipity.

Click on the "Practical tips" link at the bottom and use the back/continue links to scroll through the different plug pictures.

The optimum fuel for any gas engine is the lowest octane rated fuel that doesn't cause knocking, AKA detonation or pinging.

Norm in NJ
Next oil change at 230,000miles

Last edited by nglitz; 08-14-2004 at 11:04 PM.
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