There’s a lot of misinformation floating around about E85 fuel, especially online. Many people believe it’s corrosive and damaging to all car fuel systems. However, based on real-world experience, particularly with modern vehicles, this isn’t necessarily the case. Let’s dive into how you can actually program your car to run on flex fuel, and debunk some common myths along the way.
Understanding E85 and Modern Vehicles
The biggest myth is that E85 will corrode any fuel system. This idea largely stems from issues with cars made before the 1980s. However, vehicles manufactured after that period, including models from the 90s and onwards, are generally built with materials designed to withstand ethanol. In fact, many modern cars are already flex-fuel capable with only minor adjustments.
Take it from someone who’s been running E85 in various vehicles, from 90s Mitsubishi Talons to newer Evos, both daily and on the race track. Using stock fuel lines and tanks, the experience has been overwhelmingly positive. Instead of corrosion, the result is often a cleaner engine and fuel system. For high-performance applications, like a turbocharged Talon pushing 30psi, E85 can be a game-changer, enabling impressive performance gains, such as running 10-second quarter-mile times.
The Simple Conversion to Flex Fuel Capability
Looking into General Motors (GM) vehicles, the difference between a flex-fuel and non-flex-fuel model is surprisingly minimal. It often boils down to a sensor in the fuel tank and an extra wire to the Engine Control Unit (ECU). This suggests that many cars are inherently capable of running flex fuel with the addition of a factory sensor and wiring, or even through a simple programmer.
For those wanting to make the switch, it’s not always a complex overhaul. While direct E85 use without any modifications might trigger a Check Engine Light (CEL) due to fuel trims going out of range and a lean condition at Wide Open Throttle (WOT), this is because the ECU is trying to compensate for the different fuel properties. However, the stock fuel injectors are often capable of flowing enough fuel for E85 when paired with the correct ECU adjustments or “flash.”
ECU Programming and Flex Fuel Sensors: The Key to Conversion
To properly convert your car to flex fuel, the key is in the ECU programming. This involves adjusting the fuel maps to account for the different stoichiometric air-fuel ratio of E85 compared to gasoline. E85 requires a richer mixture, and the ECU needs to be told to deliver more fuel.
There are a few ways to achieve this:
-
Flex Fuel Sensor and Wiring: The most comprehensive approach is to install a flex fuel sensor. This sensor detects the ethanol content in the fuel and sends a signal to the ECU. Combined with the necessary wiring, a compatible ECU can then automatically adjust fuel delivery in real-time based on the ethanol percentage. This is often how factory flex-fuel vehicles operate.
-
ECU Flashing/Programmers: For vehicles not originally equipped with flex fuel capability, aftermarket ECU programmers or “flashing” tools can be used. These devices allow you to rewrite the ECU’s software, including fuel maps and potentially adding flex fuel logic. Some programmers can even work in conjunction with aftermarket ethanol content analyzers to approximate flex-fuel functionality.
-
Standalone Fuel Management Systems: For more advanced or racing applications, standalone fuel management systems offer the most control. These systems completely replace or supplement the factory ECU and provide extensive tuning capabilities, including dedicated flex fuel strategies.
E85: Performance Fuel vs. Daily Driver
While E85 offers significant performance benefits, especially in boosted applications, there are practical considerations for daily driving. The main drawback is a decrease in fuel mileage compared to gasoline due to E85’s lower energy density. This mileage drop can offset the cost savings of E85, depending on current fuel prices.
However, as a race fuel, E85 shines. Its high octane rating and cooling properties allow for increased boost and aggressive tuning, leading to substantial power gains. And contrary to the myth, long-term use of E85 in compatible systems doesn’t lead to fuel system degradation. In fact, inspecting fuel systems after years of E85 use often reveals plastic and rubber components in surprisingly good condition, sometimes even better than those running solely on gasoline.
Conclusion: Informed E85 Use
E85 isn’t some corrosive monster fuel. For modern cars, with the right programming adjustments and potentially a flex fuel sensor, it can be a viable and performance-enhancing fuel option. While daily driving mileage might be a consideration, the performance benefits and engine cleanliness offered by E85 are undeniable, especially for enthusiasts and racers. Don’t let outdated myths prevent you from exploring the potential of flex fuel in your vehicle.
