Many car owners will find that they can run their cars on flex fuel or regular gasoline, and for this reason, they will make the comparison. If you own a Flexible Fuel Vehicle (FFV) or are considering purchasing one, it’s important to know the difference between E85 and traditional gasoline to make informed decisions about refueling your vehicle. They are both used for fueling internal combustion engines, but vary widely in terms of ethanol content, energy density, fuel efficiency, environmental impact, availability and cost.
Thank you for reading this post, don't forget to subscribe!With E85 being the fuel that’s often much cheaper per gallon, many people think that using it will save them money. Others argue that, in order to keep up with the high octane rating, Flex Fuel will always be better. The situation is more complicated. It will depend on the type of car you are driving, cost of fuel in your region, driving style and if E85 fuel is available locally.
It’s not just the cost of gas a person needs to consider when deciding which one to use, whether or not it’s a Flex Fuel or regular gasoline. Fuel consumption, mileage, engine fitment, emissions and convenience are all factors to take into account. Knowing these differences will help you get the most out of your car, as well as prevent some misconceptions about ethanol fuels.
Here we’ll take a closer look at Flex Fuel vs regular gasoline, how they work in real-world driving, and what sense of the fuel will make the most sense in your case.
Understanding the Difference Between Flex Fuel and Regular Gasoline
Gas and diesel fuel are used in gasoline-powered engines, but have very different chemical makeup.
Most gasoline sold in the U.S. contains up to 10% ethanol (E10) and E85 (also commonly called Flex Fuel) is gasoline containing up to 85% ethanol. The higher ethanol blends are designed to be used in Flexible Fuel Vehicles without harming the fuel system.
The main difference is that it will be flexible. The fuel recommended by the vehicle manufacturer should be used in a standard gasoline vehicle, and an FFV can be fueled with regular gasoline, E85 or any mixture of the two.
| Feature | Flex Fuel (E85) | Regular Gasoline |
| Ethanol Content | Up to 85% | Usually up to 10% |
| Vehicle Compatibility | Flex Fuel Vehicles only | All gasoline vehicles |
| Octane Rating | Higher | Lower |
| Fuel Economy | Lower | Higher |
| Availability | Limited | Widely available |
| Renewable Content | High | Low |
The differences will help clarify why the type of fuel you use can impact the cost of operation and the driving experience.
Performance: Which Fuel Performs Better?
The performance is highly dependent on the design of the engine.
E85 is much higher in octane than regular gas. For specially-tuned engines, high-octane fuel can withstand knocking, which means they can function more efficiently with higher compression.
Most of factory Flex Fuel Vehicles, however, can be operated on either fuel. They have an engine control system that automatically adjusts the timing and fuel delivery based on the amount of ethanol that is detected in the fuel tank.
If you drive the car on a day-to-day basis, you will probably never notice any significant differences in performance.
Engines that are performance oriented or modified vehicles made specifically for E85 operation may have a symptom of:
- Improved throttle response
- Slight horsepower gains
- Improved resistance to knock in engine
However, reliability and flexibility are typically more desirable to the typical commuter than modest gains in performance.
Fuel Economy: Why E85 Uses More Fuel
One of the biggest differences between Flex Fuel and regular gasoline is fuel economy.
Gasoline has more energy per gallon than ethanol does. This makes it necessary to run more E85 in the engine to generate the same power.
Typically, drivers who use E85 will get 15–30% worse fuel economy.
For example:
| Fuel | Example MPG |
| Regular Gasoline | 30 MPG |
| E85 | 23–25 MPG |
For the first-time Flex Fuel owner, who thinks about pump prices, this reduction comes as a surprise.
When it comes to the price, top users of pickup trucks compare the price per mile, not per gallon.
However, even if E85 is much more expensive than gasoline, it could work out to be a savings opportunity due to its reduced fuel economy. When there is little or no difference in cost, it may be cheaper to use regular gasoline.
Cost Comparison: Which Fuel Saves More Money?
Fuel prices are variable and this comparison would vary depending on the area.
Suppose:
- The price of regular gas is $3.70 per gallon.
- E85 costs $3.00 per gallon
On the surface it looks like E85 is very inexpensive.
But, if your gas mileage drops by about 20% when you run E85 fuel, the savings are reduced.
Drivers should calculate:
The calculation for CPCM is Fuel Price / MPG
This is a much more useful way of comparison than just pump prices.
Those living near E85 stations that can compete with the price of regular gasoline could save over time, whereas the rest might save money on regular gasoline.
Environmental Impact
Ethanol fuels were one of the major reasons that were given for their introduction to help in the reduction of the dependence on petroleum and to promote the production of renewable energy.
E85 has a much higher percentage of renewable ethanol than gas. The majority of the ethanol consumed in the United States is made from U.S. corn.
Environmental benefits that could be achieved are:
- Reduced petroleum consumption
- Higher percentage of renewable fuels used
- Access to a variety of resources and opportunities for domestic agriculture
- Reduce air pollution of specific pollutants
It is important to look at the entire fuel lifecycle, however, to assess environmental impacts, which would include the whole of the fuel production and distribution process, as well as farming practices.
Consumers who use Flex Fuel are helping to achieve a broader vision of renewable energy and keeping vehicles running while being compatible with current vehicles using internal combustion.
Convenience and Fuel Availability
One of the biggest practical factors that still remains in favor of the two fuels is the availability.
Most gas stations in the U.S. sell regular gasoline.
There is continued growth in E85 availability, with it being limited to specific states and metro areas.
For those that have to drive long distances, using gasoline might be more convenient as fuel stations are easily found all around.
Residents who have access to several E85 stations may appreciate the ability to use whichever seems to be the best price at the moment.
If you’re planning to use E85 as your main fuel, first verify station availability of course through your regular travel routes.
Which Fuel Should You Choose?
It’s all about your preferences.
Choose Flex Fuel (E85) if you:
- Be owner of a Flex Fuel Vehicle.
- Be able to easily find E85 stations.
- Desire to help renewable fuels.
- Search for E85 that is available for much less than gas.
- Enjoy the fact that there are several different fuels available.
Choose Regular Gasoline if you:
- Operate a conventional gas-powered car.
- Wants to maximize fuel economy.
- Regularly travel great distances.
- Have limited access to E85 stations.
- Prioritize convenience.
One of the great benefits of being an FFV owner is that many of these vehicles use both fuels as and when they are available and are cheaper.
Learn More About Flex Fuel Vehicles
If this is your first time dealing or using a Flex Fuel Vehicle, you may need to read our article What Is Flex Fuel? Complete Guide to Flexible Fuel Vehicles (CCFFV) describes how FFVs operate, how they automatically blend different ethanol levels, and if FFV technology is appropriate for your driving requirements.
If you are still not sure if it is a smart investment to purchase a Flex Fuel Vehicle, read our article Pros & Cons of Flex Fuel Vehicles The long-term pros, cons, ownership expenses and the best driver profile are all discussed.
Combined these guides bring together all Flex Fuel technology and ownership information.
Trusted Resources
Learn about the state of the E85 fuel industry, ethanol blends, station locations, and alternative fuel technology from the U.S. Department of Energy’s Alternative Fuels Data Center (AFDC).
Fuel Economy.gov is a joint program of the U.S. Department of Energy and the Environmental Protection Agency that provides reliable tools and comparisons of vehicle fuel costs.
The consumer-friendly tools provide current and precise fuel information to facilitate the comparison of fuel options.
Conclusion
There is no simple answer to the question of which is better, Flex Fuel or regular gasoline. Flex Fuel provides increased flexibility, assists renewable energy and can save fuel cost when the price of E85 is advantageous. Standard gasoline, however, is normally more economical, widely available and convenient throughout the country.
This depends on a variety of factors, such as where you live, the number of miles that you drive, local gas prices, and what type of vehicle you own that runs on E85. Fortunately, Flexible Fuel Vehicles offer drivers a choice of fuel as the conditions change; something that a regular gasoline vehicle can’t do.
Knowing these differences can help you make sound fueling decisions that will consider performance, operating economy, and environmental concerns.
Frequently Asked Questions
Can I switch between E85 and regular gasoline?
Yes. Flex Fuel Vehicles are designed to operate on either fuel or any mixture of both without manual adjustments.
Does E85 increase horsepower?
Some engines specifically tuned for E85 can produce more power because of its higher octane rating. Most factory FFVs experience only modest performance differences.
Why does E85 reduce fuel economy?
Ethanol contains less energy than gasoline, so engines consume more fuel to produce the same amount of power.
Is E85 available everywhere?
No. Although availability continues to improve, regular gasoline remains much more widely available throughout the United States.
Which fuel is cheaper in the long run?
It depends on local fuel prices and your vehicle’s fuel economy. Comparing cost per mile provides the most accurate answer.
