What is Flex Fuel? Benefits & Disadvantages of Flex Fuel

What is flex fuel? Over the past few years, you’ve likely heard increasingly more about flex-fuel vehicles, even if you didn’t fully understand what they were. Today, a number of known flex-fuel benefits exist.

Over the past few years, you’ve likely heard increasingly more about flex-fuel vehicles, even if you didn’t fully understand what they were. Today, a number of known flex-fuel benefits exist. However, before investing in this type of vehicle, you should first understand what you’re purchasing. Continue reading to learn about flex fuel and its pros and cons. 

What is Flex Fuel?

Flex fuel, or flexible fuel, is an alternative fuel made of a combination of gasoline and methanol or ethanol. Flex-fuel vehicles are those that have internal combustion engines designed to run on more than one type of fuel. Other than a few modifications to the engine and fuel system, says Kiplinger, flex-fuel vehicles are virtually identical to gasoline-only models.

What is Flex Fuel

This technology isn’t new. It was first developed in the early 1990s and used in the mass-produced 1994 Ford Taurus, according to Car Bibles. By 2017, there were approximately 21 million flex-fuel vehicles on the road.

Flex Fuel Benefits

Let’s look at some of the reasons you might want to consider making the switch to flex fuel.

Cleaner for the Environment

Car Bibles states that more people today are concerned about fuel consumption’s effects on the environment. Ethanol burns cleaner than gasoline, which means flex-fuel cars pump fewer toxic fumes into the environment. Flex fuel also contributes fewer greenhouse gases, making it a more environmentally friendly option than traditional gasoline.

Burning Facility

One of the greatest advantages of a flex-fuel vehicle is that is can burn whatever proportion of fuel mixture is in the combustion chamber. The car is equipped with electronic sensors that gauge the blend, and its microprocessors adjust the fuel injection and timing.

Advanced Technology

According to Car Bibles, modern flex-fuel vehicles are built using advanced technology such as electronic sensors. As mentioned, these technological advances allow your car to adjust the way it’s operating, including detecting the fuel blend and making any necessary adjustments. Modern flex-fuel cars can contain 10 to 85 percent ethanol. Thanks to the technology it’s equipped with, your vehicle will determine the most efficient proportions.

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Sustainably Produced

Many flex-fuel vehicles run on ethanol, which is sustainably produced from ingredients such as cane sugar and corn. This makes ethanol a good alternative to purchasing foreign oil.

Tax Benefits

Consumers who drive flex-fuel cars receive tax credits that can significantly reduce or even eliminate their tax obligation.

Improved Performance

While some might argue that using an alternative fuel source can negatively impact a vehicle’s performance, in reality it can have the opposite effect. Flex-fuel vehicles don’t experience a loss in performance when using E85 fuel. In fact, some even generate increased torque and horsepower.

Disadvantages of Flex Fuel

Flex fuel does have some disadvantages you should be aware of before purchasing one of these vehicles.

Sole Crop Use

While it’s great that flex fuel can be sustainably produced using corn and sugar, its production comes with a downside. Crops designed to be used for flex-fuel production can’t be allocated to other sources. This could potentially drive up the price of animal feed. Corn is also susceptible to disease and weather conditions such as flooding and drought. This can be problematic for corn prices during poor harvests.

Possible Engine Damage

Obviously you want to treat your engine in the best way possible. Unfortunately, ethanol absorbs dirt easily, which can potentially corrode and damage your engine, says Car Bibles.

Gas Mileage

One of the main concerns about driving a flex-fuel car is its gas mileage. While some experts assert that flex-fuel vehicles have similar mileage as regular fuel-powered vehicles, others claim they have lower gas mileage.

While ethanol does raise a vehicle’s octane level, it contains less energy. In other words, it will take 1.5 times more to provide the same energy levels. So, yes, you will get fewer miles per gallon using ethanol. However, ethanol costs less than regular gasoline, so the savings should more than offset the mileage loss.

Scarcity of Fuel Stations

Because flex fuel isn’t as economical as gasoline, gas stations are less likely to carry it. In fact, only a small percentage of gas stations nationwide supply ethanol, although that is likely to change as more consumers purchase flex-fuel vehicles.

The benefit of a modern flex-fuel vehicle, though, is that you can use any combination of gasoline and ethanol, whether it’s 100 percent unleaded gas or 85 percent ethanol. Your vehicle’s sensors will detect the blend and make the necessary changes.

Flexible Fuel Vehicles

Flexible fuel vehicles (FFVs) have an internal combustion engine and are capable of operating on gasoline and any blend of gasoline and ethanol up to 83%. E85 (or flex fuel) is a gasoline-ethanol blend containing 51% to 83% ethanol, depending on geography and season.

What is Flex Fuel

According to Experian, as of 2021, there were more than 27 million FFVs in the United States. Because FFVs are factory made and are capable of operating on gasoline and gasoline-ethanol blends, many vehicle owners don’t realize their car is an FFV and that they have a choice of fuels to use.

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Other than an ethanol-compatible fuel system and a different powertrain calibration, FFVs are similar to their conventional gasoline-only counterparts. While fuel economy (miles per gallon) is generally lower with increased levels of ethanol (engines are optimized for gasoline), many FFVs have improved acceleration performance when operating on higher ethanol blends.

What Makes Flex Fuel Vehicles Different?

Although modern automobiles can tolerate a certain amount of ethanol in gasoline without serious issues, increasing ethanol content to 83 percent requires that the fuel system is made of materials that can resist its corrosive effects, especially in terms of the additional moisture in E85 fuel.

Flex-fuel vehicles use a sensor to detect the type of fuel being fed to the engine and adjust the combustion process accordingly. You can even mix a tank of standard gas with E85 with no risk of damage, although there’s no benefit to doing so.

Which Cars Can Use Flex Fuel?

There’s no universal way to determine whether or not a vehicle accepts flex fuel, but there are a few different methods. To begin with, a lot of manufacturers put a green badge on the back of the car, typically with the words “Flex Fuel,” “E85,” or “FFV” printed on it.

Another surefire indicator is a yellow gas cap. In cars with a capless fuel system, a yellow ring around the hole can replace this yellow cap. If you’re still not sure, check your owner’s manual.

You should remember that flex-fuel vehicles can also run on standard gas. Internal sensors will determine the proportion of ethanol in the mix and adjust your engine’s timing and fuel injection accordingly.

Can My Car Use Flex Fuel?

Manufacturers make flex-fuel vehicles with modified internal combustion engines using traditional gasoline and ethanol blends, such as E85. A badge with “Flex-Fuel,” “FFV,” or “E85” on the rear of the vehicle may indicate it is compatible with the alternative fuel.

Having a yellow gas cap is a good indication that the car can use flex fuel. If the vehicle has a capless fuel filler, a yellow ring around the hole where the nozzle gets inserted signals E85 works for the vehicle.

Using any octane level of gasoline in a flex-fuel vehicle is acceptable. The sensors in an FFV detect whether the fuel is pure gasoline or 85% ethanol and make necessary changes for optimal fuel injection and timing of combustion.

Putting E85 in a car not designed for flexible fuel can be harmful. Always refer to the owner’s manual for specifications on fuel to use in your vehicle.

Can You Still Buy Flex Fuel Cars?

In recent years, manufacturers have slowly drifted away from flex-fuel. As recently as 2015, eight major manufacturers were offering E85-compatible vehicles in the US. Today, only Ford and General Motors are selling new flex-fuel vehicles – and most of those models are limited to fleet sales.

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What is Flex Fuel

Not that long ago, the federal government provided financial incentives for automakers to produce flex-fuel vehicles. Today, the government has moved these incentives to electric cars. This is a good thing, but it can be frustrating if you’re not ready to leap to electric.

Thankfully, there’s a healthy used market. With over 20 million flex-fuel vehicles on America’s roads, you can still buy a used model in good condition.

Why Would I Use Flex Fuel?

Proponents of higher ethanol-gasoline blends cite lower greenhouse-gas emissions since flex fuel burns cleaner than pure gasoline, and its use reduces reliance on foreign oil. The main ingredient in processing ethanol is corn, a sustainable crop grown in the United States.

E85 costs less per gallon than regular gasoline, making it an attractive option. At this time, the AAA national average gas price for a gallon of E85 is $3.16 — 66 cents less than a gallon of regular unleaded gas.

Availability of E85 and FFVs

More than 5,700 gas stations across the U.S. sell E85 flex fuel, mostly in corn-producing eastern and midwestern states. You can find vehicles compatible with E85 nationwide because those automobiles can also use traditional gasoline.

It’s unclear how many flex-fuel vehicles exist on the road today. One study found 21 million FFVs in the U.S. in 2017. More recently, some estimate more than 27 million vehicles are using flex fuel.

The number of new FFV offerings from manufacturers has decreased. The reason: Federal incentives for automakers shifted to those building electric vehicles.

Three automotive brands — Chevrolet, Ford, and GMC — offer FFVs in the model year 2023. Only nine configurations of 2023 models are available as FFVs, down from 11 in 2022. Some offerings are sold only to fleet purchasers. According to the Renewable Fuels Association (RFA), more than 80 different models from eight manufacturers were available to consumers as recently as the model year 2015.

Other Ethanol Blends


About 98% of the gasoline sold in the U.S. contains ethanol, typically E10 with 10% ethanol and 90% gasoline.


The EPA has approved another blend, E15, in all light-duty vehicles since the model year 2001. Manufacturers responsible for more than 94% of U.S. light-duty vehicle sales endorse the use of E15 in their model-year-2023 automobiles, according to a review of owner’s manuals and warranty statements by the trade group RFA.


The RFA’s annual review indicates that E25 blends, containing up to 25% ethanol, are approved by the manufacturer for use in BMW and Mini vehicles. The 2023 Toyota GR Supra — developed with BMW — also allows E25.


E98, 98% ethanol, is a popular fuel for some types of race cars.


Can You Use Regular Gas In a Flex Fuel Vehicle?

Most FFVs can run regular gasoline, but always read the vehicle manual to double check.

Can You Use Flex Fuel In a Regular Gas Vehicle?

Regardless of whether or not it’s possible, we do not recommend using E85 in vehicles that have not been designed to run on E85. Should you accidentally fill your car with E85, repeatedly top it off with regular gas throughout the next tank or remove it with a fuel transfer pump.

Is Flex Fuel Good or Bad?

Good or bad is subjective, but flex fuel vehicles fit some lifestyles and not others.

Above is information about What is flex fuel? that we have compiled. Hopefully, through the above content, you have a more detailed understanding of Flexible Fuel Vehicles. Thank you for reading our post.

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