What is a Flex Fuel Vehicle?

January 19, 2024
What is a Flex Fuel Vehicle?

Everyone knows that a gasoline-powered vehicle runs on gas, but gasoline engines can also run on US-made renewable ethanol fuels. We call these vehicles, “flex fuel vehicles” because they have electronics in place that allow the owner to choose between gas or ethanol blended fuels like E85, which are a mix of gasoline with a high concentration of ethanol, when they visit the pump.


Almost all the gasoline pumps in the US have at least 10% ethanol, so any gas-powered ride built since the late 1980s can safely run ethanol through the fuel system without damaging the fuel pump, lines, or injectors. They were all built with ethanol in mind.  But to run higher concentrations of ethanol, a flex fuel vehicle must be able to electronically adjust to changes in the fuel type, or “flex,” because these different fuel blends require different volumes of fuel to be injected for proper operation.


You may ask why anyone would want to fill up with E85 flex fuel instead of gasoline. As it turns out, ethanol fuel has a number of advantages. Ethanol is a renewable fuel, and it burns cleaner than gas, so running is good for the environment. E85 is also less expensive per gallon than gasoline, which means lower fuel costs. But the real cost savings come from reduced engine wear. E85 keeps the engine internals clean and burns much cooler than gasoline, which reduces oil and coolant temperatures and extends the expected life of the engine.


On the performance side, a flex fuel vehicle running E85 will make more horsepower and torque than it does when burning gasoline. This is a result of the unique burn properties of ethanol and does not require special tuning or performance parts.


If your vehicle is a flex fuel vehicle from the factory, you will have a badge on the rear of the vehicle, the front fenders, or the rear windows indicating flex fuel vehicle, or FFV. The gas cap will also be yellow, and the tag inside the gas door will indicate that you have a flex fuel vehicle.


For those who want to take advantage of the benefits of flex fuel but do not have a flex fuel vehicle from the factory, Advanced Fuel Dynamics makes easily installed electronic flex fuel systems that convert the vehicle from a gas-only system to a flex fuel-capable system. Most of these solutions are plug-and-play, with no tuning required and easy DIY installation.


Whether you have a factory flex fuel vehicle or use an aftermarket solution, you can help clean up the environment while saving money on fuel and making a little more horsepower by burning E85 whenever you can. It’s a win-win.