Questions about gas differences for those in Canada

[Gruber]

what do you even think octane is

I'm tired if explaining and discussing what ON is.
It's a purely empirical definition which is explained again and again in hundreds of places. Yes, too many places, and some ignorants try to explain it too. But there is no problem with finding a good enough, correct enough explanation of the ON.
Chemically, it has all to do with the kinetics of reactions with oxygen (combustion) and because chemical kinetics is as a rule very complex, it is today still impossible to determine the ON of a substance teoretically (from the chemical structure). There are only some general, more or less theoretically based, empirical rules.

So theory not only is not very useful here, but also, anyone who doesn't understand the chemical kinetics of combustion will not understand what ON really means physically.

For these reasons, the ON for practical purposes, is only defined empirically. In the end, it is based on how a fuel behaves in an experiment involving running a standard laboratory engine, and compared to a standard fuel substance (isooctane). If a fuel burns in the standard engine like a mixture of 50/50 octane/isooctane its ON is 50. That's it. High octane fuel will burn in a nice progressing flame front, without tendency to explode ahead of the flame front at high pressue/temperature That's all there is to it by definition.

ON is correlated with the molecular structure of a compound but not directly correlated with molecular size, or volatility. Volatile or non volatile substances can have high or low octane numbers and there are plenty of examples.

Sponsored

 

[Hajidub]

Ignorants, nice! Octane is defined as how much compression the fuel can take without detonating, which is why higher octane fuel is required for forced induction engines, otherwise you get predetonation (knock). Typed all this without insulting one member!

 

[Gruber]

Ignorants, nice! Octane is defined as how much compression the fuel can take without detonating, which is why higher octane fuel is required for forced induction engines, otherwise you get predetonation (knock). Typed all this without insulting one member!

Hey, by "ignorants" i meant those people who have their websites or write articles, from "expert" positions, and spread false information. Whatever happens on a forum I treat as a conversation, and anyone can say whatever they think.
Until the person keeps repeating and defending something demonstrably false just to argue. So, definitely not refering to you.

Sponsored