Probably most petroleum additives, acetone, naphtha, Stoddard solvent, straight ethyl alcohol. With light stuff and modern vehicles you’ve got some leeway because the computer engine management system can work around the octane range adjusting timing and fuel pressure.
Older carbureted or earlier computer systems might need alternate parts or physical mods (drill the jets, or have spare carb with drilled jets).
I’m almost sure that the difference between my E85 5.3 liter engine is solely computer engine management and maybe some different seals.
The BEST teowawki fuel device would be a one way check valve and about 10-15 feet of Teflon tube. You can get gasoline out of underground tanks with the electricity out.
Speaking of seals... The penguin drops its car to the mechanic a while back, asks to have it looked at, seemed to be leaking. While its in shop, he goes out and gets ice cream, vanilla, which, with a beak is kinda messy. Comes back and the mechanic says “hey buddy, looks like you blew a seal” and the penguin is all “hey, I just went to the ice-cream shop!”...
Why is this thread still active? It might well be the thread that ENDS FR.
How long, how are do we have to go to realize it was never more than a ruse?