Would a modern (gasoline) car run on moonshine in an emergency?


I’m driving through rural West Virginia, with an insane ax murderer about five minutes behind me on the road. He has a full tank, and I am pretty much near E.

I come upon a shack up in them hills, stop my car, and run in and find some guy named Joe. I tell him my situation and ask if he has gas or a gun. He tells me that his gun is out of commission and that he has no gas, but that there’s a few jars of Old-Time Mountain Shine out back. Assume that this is the real stuff, 80%-95% ethanol.

Would a typical gasoline car run well enough on this to get me to the nearest town, say, ten or twenty miles away? The big question is whether or not I would get there alive, not what sort of abuse I am putting on my car or how crappy the gas mileage is, as long as a fill up could get me ten miles or so without my engine blowing up, stalling and not starting up again, getting clogged, etc.

If it would work, would my car require minor (or even major) repairs at my destination to fix whatever stuff I clogged/corroded/dissolved etc in my fuel system, engine, and exhaust?

I doubt it-my cite is the 3rd Back to the Future film, where they blew the engine with the stuff.

If you have a flexible fuel vehicle that’s made to work with E-85, you probably could do it. If your engine is a conventional one, it might work in theory, but I have my doubts in real life.

An engine built to run on gasoline requires a richer ratio of alcohol to air to keep running. In the old days it would have required a carbureator modification. I don’t know whether today’s fuel injectors can compensate, but even if they can you’ll be on the ragged edge.

Water and gasoline don’t mix. Water and alcohol love to mix. If you have water in your gas tank, the alcohol will slurp it right up. That doesn’t help performance, either.

Assuming you did sputter your way to the next town, I don’t think one tank of alcohol would do much in the way of permanent damage. Several tanks, however, would break loose all sorts of crud that happened to be in your gas tank, and would also begin to do a number on any parts of your fuel lines that weren’t made for alcohol.

It’s kinda funny, but your best bet is with a very recent car or a car made back in the mid 80s or earlier. Any modern car designed to run on E-85 will probably run on moonshine, though I wouldn’t expect it to run well. Many slightly older cars could be made to run, but would require an update to their engine computer. The problem is a lot of these cars don’t have an update for E-85 available.

If you go back far enough to carburetor type cars, all you need to do is adjust the mixture, which is usually a single set screw adjustment on the carburetor. Simple enough, if you know what to do. Unlike a modern E-85 capable car, older carburetor cars won’t adjust automatically.

Once you get to your destination, you’ll probably want to change the fuel filter and flush the entire fuel system. Alcohol is corrosive to cars that aren’t made for it, but 20 miles isn’t going to do enough damage to things like hoses and fittings to be worth worrying about.

One problem with your hypothetical situation though. No self respecting West Virginia moonshiner is going to have a non-functional gun. He may not lend it to you, but he’s gonna have a gun that shoots. :stuck_out_tongue:

My RX7 will run on pure denatured alcohol. I try to keep it out of boost, and dilute with a full tank of normal gas as soon as possible, but it runs fine.

If you could add either napthalene or benzene to it, it should run better than just as ethanol. I think it has something to do with either the water content or the flammability of the vapors, but moth balls and ethanol can be used in place of gasoline for some applications (tested on an old generator at my grandfather’s shop).

Not sure about moonshine, but I recall a childhood camping trip where the old Ford Country Squire wagon ran out of gas and the only fuel we had was Coleman liquid stove fuel. My mother sat behind the wheel while my father perched on the fender pouring the Coleman fuel directly into the carburetor from a gallon milk jug (with holes punched in the cap). The engine knocked something fierce (what is the octane rating of Coleman fuel?), but it ran. Of course, this would not be possible in a non-carburated car…or one too small to comfortably fit a grown man sitting under the hood. Good times…good times.

Which generation do you have? :slight_smile: FD owner, myself.

this says it’s roughly 50 to 55 octane equivalent.

Coleman fuel is just unleaded gas. Back when cars used leaded the only source for unleaded was coleman fuel. Cooking with leaded would be dangerous because of the fumes.

You dad could have put coleman fuel directly in the tank. If he had only a half a can then I can see why he didn’t put it in the tank. It might not have been enough to raise the tanks fuel level. Pouring it in the carb was a smart idea.

I have about 1/2 gallon of ‘emergency fuel’, that is suppose to be stable for years. In the instructions it says if you run out of gas put it the tank right away and start the engine and drive to get gas.

Though it doesn’t say what the fuel is I suspect it may be a high percentage of ethanol, which is known to have a harder time starting in a cold engine then gas, but really I have no idea what that stuff is and never have needed it.

Ethanol is not stable for years. It has too much of a tendency to absorb moisture to be stable in anything but an absolutely sealed container, except for possibly glass. I know it will rust metal after a long period of time.

I ran an old dodge van (1981) on mostly ethanol back in the early 90’s. Never had any problems with it, no carb adjustment needed.

I can’t think of any modern carb where a screw adjusts the main fuel ratio, that is always done with fixed jets. When I tuned my race car using Webers I had a whole kit of various jets and emulsion tubes. That screw adjusts the idle mixture only. But I am not familiar with American carbs and there might be some that actually do what you mentioned.

Now if you go back to an SU carb like my 1957 Triumph has it might work. On those carbs a tapered needle gets pulled out of the jet by manifold vacuum. There is a nut underneath that moves the jet up and down in relation to the needle. Lowering it would make the carb run richer and that is what you need. Engines need about twice as much alcohol by volume compared to gasoline to produce the same horsepower.


No it is not…

same thing here, the adjustment screws were for base idle mixture.

on the other hand, smaller diaphragm carbs like the Walbro-style ones used on small two stroke engines do have both idle and high-speed mixture screws.

Especially if he doesn’t want to lend you his moonshine. :smiley:

A couple of things to note.

  1. That Hillbilly Has at least one fully operational firearm! Probably three or more.

  2. A. He does not loan them out.

  3. He also will NOT loan you any moonshine.

  4. A. He does not want it when you are done with it.

  5. He will sell you some though. Cash talks, BS walks.

  6. He will know how to adjust your car to run on the 'shine.

  7. He thinks that your use is a major waste of his moonshine, which will affect the price.

  8. He is not impressed with you running away from this minor issue.

Now whether your rig will run on 'shine, that is a big maybe.

If the rig is diesel powered, no, it will not, & trying to will cause major damage.

Propane & LPG rigs also will not run & major damage could result from an attempt to do so.

If your rig is E-85 compliant, it should be fine.

All others, it is a crap shoot. Both on whether it will run & how much damage, if any, will be caused by the attempt.

A modern gasoline-only engine probably won’t compensate. The stoichiometric A/F ratio for gasoline is about 14.7:1, and for ethanol it’s about 9:1. I’m not sure a 14.7:1 air/ethanol mix is rich enough to support a flame, but suppose for the sake of argument that it is indeed capable of doing so. The car will try to start in open-loop mode using this ratio, and then once the O2 sensor warms up and becomes active, it’ll try to run closed-loop, using the O2 sensor for feedback. That sensor will be saying “mixture is too lean,” and the computer will try injecting more fuel to enrich the mixture. Gasoline-only engines normally do this, but they’re only expecting minor deviations from 14.7:1. Once the ratio deviates a long way from that, the computer will throw an error code, the MIL on your dashboard will light up, and, it’ll go back to open-loop mode, running on that lean mixture (again, that’s if it runs at all). Lean mixtures aren’t good for engines: they burn slow, which means they leave a lot of heat in the exhaust, which can roast exhaust valves and catalytic converters.

Octane rating isn’t an issue. Ethanol has an octane rating of well over 100, greater than the minimum octane rating for your gasoline-only car. There won’t be any problems at all with detonation/knock.

But suppose you’ve got a modern “flex-fuel” vehicle, capable of using fuels with up to 85% alcohol. If your car is near “E”, you might have a gallon of gasoline left. If you add several gallons of (mostly) ethanol, waddyaknow, you’ve just created a blend that’s somewhere between E-0 and E-85, and your car should run fine.

Suppose you coasted up to the shiner’s shack with your flex-fuel vehicle’s tank truly empty, and you fill your tank with straight ethanol. Now you’re trying to run on E-100. The car might get angry about this when it goes closed-loop and tries to adjust the A/F ratio to stoichiometric; when it sees the A/F ratio go all the way down to 9:1, it may throw an error code, since this would be well beyond the lowest A/F ratio it would expect to see in service (corresponding with E-85, not E100). I don’t know what flex-fuel vehicles do when they try to run open-loop, since the stoichiometric ratio could be anywhere from 14.7:1 to 9:1; it wouldn’t know what constitutes a “safe” A/F ratio for limp-home mode.

It may be that flex-fuel vehicles can run just fine on E-100. The reason you don’t see E-100 at the pump is that it makes cold-starts a bitch. That shouldn’t be a problem with a brief stop to tank up at the shiner’s shack before you flee to safety, since your engine is still hot, but when you try to start your cold car the next morning, you might have a problem because the ethanol won’t evaporate so well. Gasoline is a blend of various hydrocarbons, and gasoline engines purposely deliver a rich mixture at cold-start because then there’s enough of the lighter fractions of the fuel to evaporate and create a combustible mixture, even though the heavier fractions won’t evaporate (until the engine warms up, at which point the enrichment gets backed off). But if you’ve got E-100, then there are no lighter fractions to evaporate when cold: a cold fuel-air mixture that’s saturated with as much ethanol as possible won’t be rich enough to burn, and squirting more ethanol in won’t create a richer mixture (the mixture is already saturated). This is why flex-fuel vehicles need E-85: that 15% gasoline is what facilitates cold-starts.

to that last part, in Brazil where cars often run on neat ethanol, but in regions where it gets colder many cars have a small auxiliary gasoline tank for cold starts.