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pure ethanol according to wikipedia has an octane rating of 108 on the scale that's normally referred to. 100 is the octane of a particular isomer of the hydroc

pure ethanol according to wikipedia has an octane rating of 108 on the scale that's normally referred to. 100 is the octane of a particular isomer of the hydrocarbon C8H18 which is called... octane! https://en.wikipedia.org/wiki/Octane_rating#Examples https://en.wikipedia.org/wiki/Octane_rating#Examples and for people not familiar with the subject, the purpose of an octane booster is to make your fuel less explosive (even though the point of your fuel is to be exploded to release it's energy) The problem with low octane fuels is not that they have lower energy, but that when you compress them they can explode prematurely (before you're ready to collect the energy) and compressing them is a way to get more energy out of an engine. Ethanol is less explodey, and so is tetraethyl lead.

fuzzfactor 4y ago
Molecular models are like tinkertoys. Carbons are the little black spheres with 4 equidistant holes, and hydrogens are the smaller white ones with a single hole. And you've got all the little somewhat-flexible rods to act as chemical bonds and connect the different carbon and hydrogen atoms in any combination you like. Octane is a generic name for most any combination you can legitimately make out of C8H18. Any of these is referred to as an octane isomer. If you put all 8 carbons in a straight row and "saturate" the remaing holes with the 18 hydrogens, this straight-chain form in particular is referred to as Octane proper, or more descriptively to avoid confusion, normal-octane since it is a straight-chain isomer. This normal- or n-octane is not the stuff that burns with a very good antiknock rating at all. The one particular branched-chain C8H18 isomer having the proper name 2,2,4-trimethylpentane is the one that serves as a calibration fluid for laboratory antinock determination. Even though there are many other branched-chain C8H18 isomers possible, this one is the most commonly obtainable and carries the generic name "Iso-octane". Runs smooth as butter. Goes well with vintage MTBE.

fuzzfactor 4y ago

Molecular models are like tinkertoys. Carbons are the little black spheres with 4 equidistant holes, and hydrogens are the smaller white ones with a single hole. And you've got all the little somewhat-flexible rods to act as chemical bonds and connect the different carbon and hydrogen atoms in any combination you like. Octane is a generic name for most any combination you can legitimately make out of C8H18. Any of these is referred to as an octane isomer. If you put all 8 carbons in a straight row and "saturate" the remaing holes with the 18 hydrogens, this straight-chain form in particular is referred to as Octane proper, or more descriptively to avoid confusion, normal-octane since it is a straight-chain isomer. This normal- or n-octane is not the stuff that burns with a very good antiknock rating at all. The one particular branched-chain C8H18 isomer having the proper name 2,2,4-trimethylpentane is the one that serves as a calibration fluid for laboratory antinock determination. Even though there are many other branched-chain C8H18 isomers possible, this one is the most commonly obtainable and carries the generic name "Iso-octane". Runs smooth as butter. Goes well with vintage MTBE.