Ethanol fuel hose

DIY E85 Fuel Conversion Guide

Converting your car to run on E85 fuel can be a great way to save money on gas while also reducing your environmental impact. E85 is an ethanol blend fuel containing 51%-83% ethanol, with the remaining percentage being regular gasoline. While not all vehicles can run E85 fuel properly without modification, many modern fuel-injected vehicles can be converted relatively easily and inexpensively.

Benefits of Running Your Car on E85

Key Takeaways
Significant cost savings from using cheaper E85 fuel
Reduced emissions and environmental impact
Increased performance possible with high octane rating
Flex-fuel vehicles best suited for conversion
$800-$1500 for parts, $500+ for professional installation

Here are some of the main benefits of converting your car to use E85 fuel:

  • Cost savings – E85 fuel is generally 20-30% cheaper per gallon than regular gasoline. The fuel economy when running E85 is lower, but the overall cost savings can be significant for high-mileage drivers.
  • Renewable fuel – Ethanol is a renewable biofuel, usually made from corn and other plant materials. Using E85 reduces dependence on fossil fuels.
  • Fewer emissions – Cars running on E85 tend to have lower emissions than with gasoline, including lower greenhouse gas emissions.
  • High octane – E85 has an octane rating around 100, which can provide a performance boost in some vehicles designed to run at higher compression ratios.

Vehicle Compatibility Considerations

Car engine with injectors

However, not all vehicles can properly run E85 fuel without modifications. Here are some things to consider:

  • Fuel system compatibility – The fuel lines, seals, and other components need to be ethanol compatible. Parts made from zinc, brass, copper, and aluminum can be degraded by long-term exposure to ethanol.
  • Sensor compatibility – Oxygen sensors and fuel level sensors need to work properly at varying ethanol concentrations.
  • Fuel rail and injector sizing – More fuel is needed on E85 to maintain performance, which may require larger fuel injectors.
  • Software tuning – The ECU may need recalibration to account for the different fuel properties.
  • Cold start – E85 can be harder to start in cold weather, so a block heater may be needed in some climates.

Overall E85 use is ideal for flex-fuel vehicles (FFVs) specifically designed for high ethanol blends. Many vehicles from the last 10-20 years can also be converted with some upgraded hardware. Older vehicles are generally not suitable candidates without major work.

Items Needed for E85 Conversion

Converting to E85 will require some or all of these parts:

  • Ethanol-compatible fuel lines and seals
  • Adjustable fuel pressure regulator
  • Larger fuel injectors
  • Flex-fuel sensor
  • ECU/PCM recalibration tuning
  • Heated fuel rail (may be needed)

Additional items like a fuel pump upgrade may also be necessary depending on the vehicle. Expect to spend $800-1500 on parts for a full conversion. Professional installation can add $500 or more to the cost. Doing the work yourself can save substantial money.

Step-by-Step Conversion Guide

With the right parts and mechanical skills, here is an overview of the E85 conversion process:

1. Verify Vehicle Compatibility

Review your owner’s manual and technical specifications to see if your car already supports E85 from the factory. If not, confirm your vehicle is a good candidate.

2. Select the Right Hardware

Choose fuel system components able to withstand ethanol corrosion for the long-term. Carefully calculate new fuel injector sizes.

3. Install the New Hardware

Replace fuel lines, seals, regulator, injectors, sensor, and other components with the new ethanol-compatible hardware.

4. Tune the Engine Management System

Use a tuner tool to recalibrate the engine computer for the new equipment and fuel properties.

5. Test and Retune as Needed

Drive the car, monitor fuel trims and oxygen sensor readings. Fine-tune the system to optimize performance and drivability.

6. Fill Up on E85!

Once tuned, you are ready to regularly fuel up with delicious corn juice rather than dinosaurs!

Finding E85 Fuel Stations

While E85 is not yet as widely available as gasoline, there are still over 4,000 fueling stations offering E85 blends in the United States. Resources like the Alternative Fuels Data Center Station Locator can help find stations in your area. Use a flex-fuel sensor or ethanol content tester to verify actual ethanol percentages.

Is E85 Conversion Right for You?

Converting your existing car to run on renewable E85 rather than just gasoline is a worthwhile project for the right vehicle. With some mechanical ability and the correct hardware, it can be a cost-effective way to save on fuel while also reducing environmental impact. And you’ll have the satisfaction of making your car run on corn!

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