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Re: Octane rating Drop (needsdecaf)

I'm no gas expert, but if the more volatile HC's vapor off (lower chain lengths like pentane, hexane and septane, wouldn't the larger average molecule size SLOW the combustion rate and RAISE the "octane" rating?

Wasn't octane (C8H18) originally picked because is was the "ideal" in knock resistance (100% octane = 100 octane anti-knock rating). I know there's a lot of other stuff in gasoline (aromatics, etc.) besides simple
(CnH2n+2) straight chains (aren't those called paraffins?), but logic would suggest that getting rid of the most volatile would slow the burn rate and raise the knock resistance. Set me straight if that's wrong.
 
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