Most gasolines contain at least a small amount of ethanol or methanol as an anit-cing agent. Alcohol mixes well with water and fairly well with gas, so it tends to keep small amounts of water mixed into the fuel, rahter than settling out. If water settles it can freeze, so keeping it mixed works. Typical, about 1/2 percent alcohol is sufficient to do this. At this level, it doesn't hurt any car parts.
Stoichiometric ratio for case is about 14:1, for alcohol it's about 6:1, so if you are going to run pure alky you need to rejet your carb big-time. Ask the drag racers who run it. It does butn cool, so it supports a higher compression ration that a gasoline engine. An alky race engine can be 14:1 or more, compated to 10:1 for tha same motor on gas.
Because you need more fuel per unit of air, you will see less mileage per gallon with alky-based fuel. You are also effectively running a leaner mix than before, though depending on the amount of alky you may not need to rejet. Or you might.
OTOH, since the effective octane may be higher, you might be able to advance the timing a bit and get back a little performance and economy.
The various types of rubber, cork, and varnishes used in old gaskets and other parts are not alcohol-friendly, so if you're running an old carb you *may* have problems with leaks or other failures. I'd guess every carb out there has been rebuilt with modern parts by now, but you may be the exception.
The bottom line is, for better or for worse if you live in a state that mandates it, you're gonna get it. Adapt. Is it a wise policy for the gummint to mandate it? I think that's
out of scope for *this* discussion forum. ;-)
Cheers!
George
