All sorts of additives go in there. Isooctane and other hydrocarbons (aromatic and otherwise) are added to raise and regulate octane ratings...which will differ based on your altitude.

Commonly 87 octane for regular at sea level and 86 or even 85 at higher altitudes. That's because the air is thinner and you don't need as much octane. Companies like Chevron and others boast the addition of products like Techron and other branded additives which don't come rapidly to mind, and all of them add dyes, "detergents" and many other things.

And...ethanol is C2H5OH. If you look around, you'll find there are some other compounds sharing similar (by small degrees different) formulas. But like water (H2O) and hydrogen peroxide (H2O2...simply one more atom of oxygen), they'll be different enough so as not to be substitutable. As anyone who has ever enjoyed a tall cool glass of hydrogen peroxide might tell you. One more thing...ethanol is added to gas trucks at the terminal. That's because of ethanol's high affinity to water and the desire to keep as much H2O out of it as possible before it goes to the gas stations.

Do they increase the creeping? I don't know, but my guess would be yes.

Last edited by Jon G; 02/19/2022 4:37 PM.
~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end