Understanding 5.7 Hemi Flex Fuel Technology

January 19, 2024
Understanding 5.7 Hemi Flex Fuel Technology
Some automotive manufacturers create flex fuel vehicles to allow owners to choose between gasoline and ethanol-based fuels, like e85. This technology enables vehicles to run on a blend of ethanol and gasoline, with ethanol concentrations typically ranging from 51% to 83%. The critical component of a flex fuel engine is its advanced fuel system electronics, which can automatically adjust fuel injection loads depending on the type of fuel used. This adaptive capability is enabled by the vehicle's electronic control module (ECM), which receives data from fuel sensors to determine the appropriate air-to-fuel ratio for optimal combustion.


While all OE fuel systems built after the late 1980s have ethanol compatible components, it is the electronic management system that varies between engine control systems, managed by the PCM. The PCM in a 5.7 Hemi equipped vehicle is not capable from the factory of managing flex fuel, so these vehicles are unable to take advantage of the lower fuel costs, higher horsepower, extended engine life, and cleaner emissions of high-content ethanol fuels like E85.


The 5.7 Hemi Flex Fuel Engine


The 5.7 Hemi Flex fuel engine is possible with the Advanced Fuel Dynamics ProFlex plug-and-play flex fuel management system. This is a powerful and versatile powertrain option for all 5.7 Hemi vehicles, offering impressive specifications and performance capabilities.


Cost savings and long-term consumer benefits are other essential aspects of using a 5.7 Hemi flex fuel car. While the 5.7 Hemi Flex Fuel engine offers impressive power and performance, proper maintenance and fuel costs are essential for vehicle owners to consider. The recommended fuel for optimum performance and fuel economy is 89 octane "Plus" gasoline. The 5.7 Hemi is prone to knock and loses durability and horsepower when run on lower grades of gasoline.


E85 is very high in octane, which means no knock. With E85 in the tank, the engine computer can advance timing, bringing more of the power potential of the engine to the street. E85 also makes additional power because of its unique burn properties, as much as 35 more wheel horsepower than a stock 5.7 vehicle. No tuning is required to see these gains because the horsepower comes directly from the way the fuel burns.


While E85 can slightly reduce fuel mileage, the cost of E85 for your 5.7 Hemi flex fuel engine vs. the cost of high octane gasoline is significantly lower per gallon, so you may visit the pump a little more often, but your fuel costs will typically be lower overall, and you get all of the horsepower, emissions, engine durability, and lower engine operating temperatures in the bargain.


The 5.7 Hemi is a great candidate for a flex fuel system with clean, renewable, and powerful E85. Now Hemi owners can take advantage of these benefits with a simple electronic solution that will pay for itself based on fuel cost savings and fewer engine repair bills. All of these reasons make owning a 5.7 Hemi flex fuel vehicle an attractive proposition.