Can You Really Run a Car on Moonshine?

In the new movie Lawless, brothers Jack Bondurant (Shia LaBeouf) and Forrest Bondurant (Tom Hardy) find themselves unexpectedly out of gas on a tense drive out of Franklin County, Va. Luckily, they’re booze-running bootleggers, and after emptying a mason jar of moonshine into the tank, their automobile is back up and running. Can cars really run on moonshine?

Only if it’s really strong stuff. To power a car, moonshine—in this case, illicit homemade whiskey—must  have an extremely high alcohol content, at minimum 150 proof (or 75 percent alcohol by volume), or 190 proof for best results. During the Prohibition, moonshine could be as weak as 63 proof and as strong as 190 proof.

Alcohol has been used to fuel cars since the dawn of the modern automobile. Henry Ford’s Model T was equipped for running on ethanol as well as gasoline. And in recent years, the federal government has mandated that ethanol make up about 10 percent of most gasoline bought at the pump. Others drive on the more controversial E85, which is 85 percent alcohol. Some penny pinchers have even installed legal “moonshine” stills in their own backyards, to save on gas money.

Practically any car could run on high-potency hooch, though the level of performance would vary. The Ford Model A driven in the historical novel Lawless is based on would run pretty smoothly, though it would lose about 30 percent of its horse power. Most automobiles made prior to 2000 aren’t equipped to handle alcohol long-term, and fueling with ethanol can lead to leaks, rust, and corrosion. However, since alcohol has become a regular additive to gasoline, modern fuel systems have developed a much higher tolerance for the substance. While a car made today could run just as well on some stiff “white lightning” as it could on E85 fuel, drivers should beware of cold winters: Below 40 degrees, it’d be a challenge to get it started.

-  Slate.com