Quote:
Originally Posted by Formulabruce
If folks tuned their engines ( along with altitude, temp, usage at their location) by BTU, instead on Octane, a real feeling for whats going on inside would make tuning more accurate if you are going for details.
Octane, like Cetane, is a Flame Retardant. This " Can" , with dense fuel , make more power.
Alcohol has a higher Octane, but its a puke on BTU, much less power. So in modern fuel with Alcohol it can be misleading when compared to Suncoast 260 of the past.
Octane doesn't always mean better, or more power in the case of Ethanol.
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thats very true. but what happens when you increase the volume of ethanol to compensate for the lower BTU? i have never had an engine set up for that but i know some people that do & most say ethanol has some benefits like cooler & cleaner burning etc. for high compression or turbo/forced induction engines the higher octane E85 is what lots of guys use. plus its cheaper than any comparable octane fuel.
as you mentioned, i have never really noticed a difference in 91 straight gas vs 93 with 10%E in 3 different pontiac engine cars, the higher HP one at the drag strip or driving any of them around town. i try to stick with straight 91 but will get the 89 or 93 ethanol if its cheaper.