What Is Flex Fuel?

Flexible fuel gives owners an alternative choice at the pump. Theoretically it could also have environmental benefits.

Byline: Tony Markovich

In the modern era, flexible fuel, also known as flex fuel and most commonly referred to as “E85,” starts its consumer story with the Ford Taurus Flex Fuel Vehicle (FFV) that debuted in the mid-’90s. Its 3.0-liter V6 engine could run on conventional gas or a fuel with a higher ratio of ethanol to gasoline. Flex fuel was originally touted as an alternative fuel that could help America become more energy independent, and its use expanded to numerous manufacturers and dozens of vehicles throughout the past three decades. 

Though overshadowed today by hybrids and electric vehicles, which serve as much more extreme answers and solutions to oil dependence and climate change, there still exists a small stable of cars, trucks, and SUVs that are built to run on flex fuel.

To help our readers better understand this fuel, and to explain its benefits, we’ve put together a guide to its properties, how it’s used, where it comes from, and where you can find it. Time to gas up.

What Is Flex Fuel?
The “E85 Coupe” was a concept car GM cooked up for the SEMA show in 2007 to hype flex fuel. Image: GM; Adobe Stock (Aliaksei)

What Is Flex Fuel (E85)?

Flex fuel is a fuel mixture of 17-49 percent gasoline and 51-83 percent ethanol. The mixture ranges depending on location and season. 

Where Can You Buy E85?

E85 fuel is available at many gas stations across the country. E85Prices.com has an interactive map of where you can find E85 pumps; you might also be able to find local E85-serving gas stations on Google Maps.

What Is Ethanol?

Ethanol is a non-consumable clear grain alcohol that comes from plants. In the United States, ethanol is primarily sourced from corn, but it can be harvested from other starchy and sugary vegetables like sugarcane, barley, or sorghum. Ethanol is used to cheaply boost octane ratings and is a component of nearly all common consumer gasoline. Typically, most traditional pump gas you put in your car has up to 10 percent ethanol.

FuelEconomy.gov has more details on how ethanol is used in vehicle fuels today.

What Is Flex Fuel?
An ethanol refinery in the American Midwest. Image: Adobe Stock (wolterke)

What Is a Flex Fuel Vehicle?

An FFV is a vehicle that gives its owner the choice to run on more than one type of fuel, most commonly conventional gasoline or E85. FFVs are nearly identical to regular vehicles, with the exception of a few different or altered parts within the fuel system. For example, a Ford F-150 FFV features fuel lines with a nickel coating, higher-volume fuel pumps, and fuel delivery modules with aluminum rotors as opposed to composite rotors. Sensors within the fuel system detect the blend, and the vehicle’s computers figure out the rest.

What Is the Benefit of Flex Fuel?

Flex Fuel offers several advantages compared to regular gasoline and is considered a complementary near-term solution to helping the environment. Other benefits include: 

  • Cheap way to boost octane rating
  • Burns cleaner
  • Renewable energy source
  • Expands fuel options and reduces dependence on petroleum
  • Cheaper than conventional gas, at times
  • No loss in performance, and possible to create more torque and horsepower

What Are the Negatives of Flex Fuel?

Flex Fuel offers many positives, but on the other side of the coin, there are a couple of negatives. They include: 

  • Energy density. As stated by the DOE, Ethanol is less energy dense per volume than gas. As a result, FFVs will likely get 15-27 percent fewer miles per gallon than when using conventional gasoline. For example, the DOE performed a study on a 1998 Taurus FFV and compared it to a Taurus that ran on gas. “The estimated driving range for the FFV Taurus operating on E85 is 250–340 miles, and on gasoline it is 340–470 miles,” the study said.
  • Availability. This is not necessarily a knock on the actual flex fuel product, but some who get accustomed to using E85 on a regular basis might get frustrated when they can’t find a fuel pump that offers E85. According to the DOE’s fueling station finder, there are 3,905 locations that offer E85, but a large majority are found in the eastern half of the country. States like Utah, Nevada, Idaho, Wyoming, Montana, Washington, Oregon, and Arizona are extremely limited.

Flex Fuel Vehicles Sold Today

The Alternative Fuels Data Center from the U.S. Department of Energy lists the following options for vehicles with flex fuel capabilities. 

  • 2020 GMC Yukon (4WD)
  • 2020 GMC Yukon XL (2WD and 4WD)
  • 2021 GMC Sierra (2WD and 4WD)
  • 2020 Chevrolet Impala (discontinued)
  • 2020 Chevrolet Suburban (2WD and 4WD)
  • 2020 Chevrolet Tahoe (2WD and 4WD)
  • 2021 Chevrolet Silverado (2WD and 4WD)
  • 2021 Ford Explorer (AWD)
  • 2021 Ford F-150 (2WD and 4WD)
  • 2021 Ford F-250 Super Duty
  • 2020 Ford Transit Cargo Van (2WD and 4WD)
  • 2021 Ford Transit Connect Wagon LWB
  • 2021 Ford Transit Passenger Van (2WD and 4WD)

The site E85Vehicles.com also has a list of E85-compatible cars and trucks.

How To Identify Flex Fuel Vehicles

Identifying a flex fuel vehicle is easy. If you don’t feel like reading the owner’s manual, which will contain information about the fuel your vehicle can run on, look for a label on the inside of the fuel door, a yellow fuel cap, a yellow ring around the fuel filler, or exterior badging on the door, side fender, or the rear of the vehicle.

The site FuelEconomy.gov has more details on figuring out whether or not a car is E85 compatible.

FAQs About Flex Fuel

You’ve got questions, Car Bibles has answers!

Q. Can you use regular gas in a flex fuel vehicle?

A. It’s always best to consult your owner’s manual to check specifics, but you will nearly always be able to use regular gas in a flex fuel vehicle.

Q. Can you use flex fuel in a regular vehicle?

A. No, you cannot. Do not put flex fuel in a regular vehicle, as they are not designed to run E85, and doing so could put unnecessary wear and tear on your vehicle’s components.

Q. Can you mix flex fuel and regular gas?

A. All this would do is change the mixture ratio of gasoline to ethanol. However, engines are designed to run on fuel that meets specific parameters and conditions. If you start to mess with that, it could affect your vehicle’s internals in the long run.

Q. Is flex fuel good for the environment?

A. Eliminating the car and fuel-burning engines would be good for the environment. Flex fuel is not good for the environment, but it is technically cleaner-burning than gasoline and comes from a renewable source.

Q. What is M85 flex fuel?

A. M85 is an alternative fuel blend that uses methanol instead of ethanol. Small programs have run in the US to test the viability of M85, but it’s extremely limited, so you probably won’t encounter it.

Q. What’s the difference between a flex fuel vehicle and an alternative fuel vehicle?

A. A flex fuel vehicle presents the option to run the vehicle on multiple types of fuel, which might include the ability to run on an alternative fuel like E85. An alternative fuel vehicle might be able to run on something like biofuel, but it might not be able to run on multiple types of fuel, only that one specific alternative fuel.

Video

Even if a vehicle is not designed to run on E85, it’s possible to convert a normal vehicle into a flex fuel vehicle. This video discusses what flex fuel is and what is involved in the equipment used to run E85. 

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