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Is ethanol in your gas a problem? We revisited the question with an expert

A couple of months ago, we ran a column on the effects of ethanol in gasoline. We didn’t think it would be terribly controversial, because we reported only what we could confirm from reputable sources (mostly the United States Department of Energy). The story sparked reader interest like a match in a pool of spilled gasoline. By the time the comments section quieted down, we’d been accused of shilling for the oil industry, the ethanol industry, the left wing, the right wing, and everything in between.

To address the valid questions and concerns raised by our readers, we’re wading back into the ethanol discussion.

For this article, Digital Trends spoke in-depth with Dr. Andrew Randolph, Technical Director for ECR Engines. Dr. Randolph holds a Ph.D. in Chemical Engineering from Northwestern University, with a specialty in the combustion properties of ethanol-gasoline blends. He’s been working with NASCAR since 1999 and started with ECR in 2008.

ECR Engines is a high-performance engine production, research, and development company located on the Richard Childress Racing campus in Welcome, North Carolina. ECR Engines have earned more than 250 victories, including twice at the Daytona 500 and three times at the Brickyard 400. ECR engines have won championships in the NASCAR Nationwide and Camping World Truck Series, and the ARCA Racing Series presented by Menards. NASCAR races on 15 percent ethanol and 85 percent gasoline fuel.

Your lawn mower is not like your car

One of the most common complaints about our last article was that we ignored the effect of ethanol on small engines such as lawn mowers, chainsaws, weed whackers, and the like. Well, this is the Cars section of Digital Trends, not Home & Garden — but we’ll roll with it. We asked Dr. Randolph why ethanol can have such different effects on small engines.

If they were to certify all these engines using E10 as the certification fuel, then you wouldn’t have any problem.

“There is a difference between cars and lawn mowers, weed whackers, chainsaws, and things like that,” he tells Digital Trends. “Cars have a sensor in the exhaust which always optimizes the relationship of gasoline to air such that you have a perfect mixture regardless of what kind of gasoline you use.”

An Oxygen or O2 sensor communicates with a modern car’s engine control unit computer, telling it how to adjust the fuel-air mixture to stay in balance. In contrast, a small engine uses the simplest carburetor possible, with a fixed air-fuel mixture.

“When you add ethanol to gasoline, the ethanol has oxygen in it, so it changes the optimum ratio of the amount of fuel to the amount of air,” Randolph says. “You have some of the oxygen constituents in the fuel itself. A car will adjust for that automatically but lawn mowers are not able to adjust the ratio of fuel to air based on ethanol in the fuel.”

Related: Do you really need to buy premium gasoline?

One problem is that the small engine manufacturers typically design and certify their engines to run on pure gasoline without any ethanol content. But about 97 percent of the gasoline sold at public service stations in America contains 10 percent ethanol.

Dr. Andrew Randolph

Dr. Andrew Randolph

“If they were to certify all these [engines] using E10 as the certification fuel, then the jetting and the carburetors on those devices would be set up to work optimally with E10,” Randolph explains. “And then you wouldn’t have any problem with those devices either.”

As a final note on small engines, Randolph warns against using E85 fuel, but states that conventional E10 should not be a problem in most cases.

“If someone thinks they had a problem in their chainsaw or their lawn mower because they’re using E10, they very likely would have had those problems anyway,” Randolph says. “When you start getting into higher concentrations like E85, if you tried to put that into your lawn mower or your weed whacker, then you will start having problems because that’s outside of the range in which the device is intended to operate.”

What about classic cars?

Another question we got was how owners of classic cars can manage ethanol in gasoline. Like small engines, classic cars tend to use carburetors, which were not designed to use fuel containing ethanol, and carburetors lack a feedback loop to adjust fuel-air mixture in real time.

“It’s kind of a case-by-case basis,” Randolph says. “But once you get into the 1990s, auto manufacturers started realizing that alcohol was going to be coming in gasoline, and they made sure that all the materials in the fuel system would not have any kind of breakdown with exposure to ethanol. It varied by manufacturer and by engine whether the fuel system was susceptible to that, but certainly by the time you got to the turn of the 21st century, no fuel systems were manufactured with components that would have difficulty with alcohols. But there are some older cars that do [have problems].”

The best thing you can do with a classic car is replace any fuel hoses or fuel pumps that might be sensitive to ethanol with modern parts, and then have your classic properly tuned at a shop that can monitor the fuel-air mixture on a rolling dynamometer that simulates real-world driving. Alternately, if it is available in your area, you can seek out ethanol-free premium gasoline, although this fuel tends to cost more than conventional E10 gasoline.

The future of ethanol

Despite the efforts of ethanol opponents, Dr. Randolph believes that we will continue to have alcohol in our fuel, and that the amount of alcohol in gasoline is likely to rise.

“It’s largely driven by economics,” Randolph says. “The price of gasoline is dependent on the price of oil. On the other hand, the economy of ethanol in the United States is linked to the health of the corn crop. It’s linked more to weather than politics. Long term, ethanol is a much more stable commodity to rely upon, because you don’t have governments and wars that are going to put your supply at risk. Also, the dollars that you’re spending on ethanol are paid to U.S. farmers and U.S. infrastructure.”

Consumers want whatever’s going to be cheapest at the pump. That’s the long-term driver. I think ethanol’s going to win.

Ethanol is also preferred as an oxygenating additive because it is less toxic than prior octane-boosting additives like tetraethyl lead and Methyl Tertiary Butyl Ether (MTBE).

“Ethanol is a biodegradable fuel additive, and it provides excellent octane in fuel,” Randolph points out. “As we move towards the future and higher-performing engines that have to get better fuel economy, octane has to go up. The question is, how do you get there? If you get there by adding aromatic hydrocarbons or MTBE or tetraethyl lead, those are all very effective octane increasers but in each case there’s something about them that has very serious adverse health consequences. From that standpoint, ethanol is something that you would expect to be increased as we move forward.”

In the end, arguments about lawn mowers and classic cars won’t move the needle nearly so much as the widespread desire to pay less at the pump.

“I think that longer term, we’ll see more ethanol in gasoline,” Randolph says. “I think consumers want whatever’s going to be cheapest at the pump. That’s the long-term driver. I think ethanol’s going to win.”