July 24th, 2017, 06:05 AM
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#23
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The Violet Vixen
Name: Yakaru
Location: Issaquah, WA & Las Vegas, NV
Join Date: Jun 2012
Motorcycle(s): Perigee (250), Hotaru (250), Saturn (300), Pearl (300), Zero (S1000RR), Chibi (Z125), Xellos ('18 HP4R)
Posts: A lot.
MOTM - Jun '16
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Quote:
Originally Posted by JacRyann
No. Flame-front propagation speed is identical across all octane levels. The higher branch-chain and aromatic content of higher octane fuels just resist formation of radical alkyl groups better. Those radicals are sensitive and can spontaneously ignite ahead of flame front. Note at this point, ignition and combustion is well underway. It just hasn't completed yet when detonation event occurs.
Mileage is purely based upon number of hydrocarbons per gallon, regardless of octane level. Ethanol is an easy octane-booster @ 114-octane. It is used to cut lower-octane gas. However, due to its onboard oxygen, which is HUGE, this displaces hydrocarbons per gallon, leading to lower mileage.
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Interesting, goes against what I was taught; but that was years ago and not the most formal setting. The mileage sub-point is simply one of efficiency -- if the gas is going off too early or too late then the energy is there, yes, but you'll get less mileage since it's not driving the engine's piston as efficiently as it could.
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"most folks racing this bike get it in a competitive state of being with much less invested than you've already put in Saturn." - Alex
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