Switching To E85: A Guide For Fuel System Conversion

E85 is a combination of ethanol and gasoline, with ethanol making up between 51% and 85% of the mixture. It is a popular choice for those seeking high performance from their engines, as it has a high octane rating and a cooling effect on the intake charge. However, it is not without its drawbacks, and there are several things to consider before making the switch.

Upgrade your fuel pump

Upgrading your fuel pump is one of the first steps to take when converting your vehicle to E85. The ethanol in E85 requires a richer air/fuel mixture than gasoline, and you will need a fuel pump that can deliver a higher volume of fuel to your engine.

The Walbro 255 HP fuel pump is a popular choice for vehicles making under 400 whp, while the Walbro 485/450 is recommended for vehicles making more than 400 whp. It is important to note that you may need to upgrade your fuel lines and wiring when installing a new fuel pump.

Some vehicles may require two fuel pumps to support the higher fuel demand of E85. In this case, you can use a Hobbs switch to connect the second pump, which will only come on when triggered by boost or nitrous. This setup can also help reduce heat and amps.

When choosing a fuel pump for E85, it is important to select one that is compatible with ethanol and has sufficient flow capacity to meet the demands of your engine. Brushless fuel pumps are the most durable option, but quality brushed pumps with carbon commutators can also be used. It is recommended to avoid pumps with copper commutators. For in-tank pumps, composite turbine impellers are a better choice than positive displacement gerotors.

Upgrading your fuel pump is a crucial step in converting your vehicle to E85 and ensuring that your engine receives the fuel it needs to perform effectively.

Upgrade your fuel injectors

Upgrading your fuel injectors is a crucial step when converting your vehicle to E85 fuel. This is because E85 demands a higher volume of fuel to achieve the same amount of thermal energy as gasoline. As a result, your vehicle's fuel injectors and pump will need to be able to supply the extra fuel required to run on E85.

The Injector Dynamics 1000cc injectors are a popular choice for those making the switch to E85. These injectors are a standard Bosch injector that has been flow-matched to be a perfect set. They can run on both gasoline and E85 and provide enough fuel for the stock turbocharger, as well as some larger turbo upgrade options.

It is important to note that the size of the injector you need will depend on your specific vehicle and performance goals. For example, a good starting point for most vehicles is a 1000cc injector, but you may need to go as low as 750cc or upwards of 1300cc or more depending on your setup.

When choosing fuel injectors, it is also crucial to consider the fuel pump you will be using. The pump needs to be able to supply enough fuel at the required pressure to keep up with the increased fuel demand of E85. A general guideline is to look for a pump with a flow rate of at least 300 litres per hour and E85 compatibility.

Additionally, it is worth noting that E85 is a solvent and can break down materials that are not compatible. Therefore, it is essential to ensure that your fuel injectors, as well as other components of your fuel system, are compatible with E85. Modern fuel injectors, such as the ID1300's and ID1700's, have stainless steel internals and are rated for E85 use.

Finally, some preventative measures can be taken to maintain the health of your fuel injectors when using E85. It is recommended to run 93 octane gasoline through your injectors occasionally as it has lubricating properties that are not present in E85. Using additives and fuel filters can also help prevent any black buildup on the injectors.

Re-tune your vehicle

Retuning your vehicle is a crucial step when converting to E85 fuel. If your vehicle is not retuned, it will run lean, which can cause serious engine damage.

Retuning your vehicle involves creating a new engine fuel and timing "map" that allows your vehicle to run on E85. This is because E85 fuel requires a higher fuel volume than gasoline. You will need to adjust the tune on your car to account for the larger fuel injectors and the new demand for more fuel.

There are two main ways to retune your vehicle for E85: a flex-fuel tune or a non-flex fuel tune. A flex-fuel tune is more convenient as it allows your vehicle to adjust to varying concentrations of ethanol in the fuel. This means you can fill up with any combination of E85 and regular gasoline, and your vehicle will automatically adjust. To do a flex-fuel tune, you will need to install an ethanol content sensor that communicates with your vehicle's ECU.

If you choose a non-flex fuel tune, you will need to create two separate fuel maps: one for E85 and one for regular gasoline. This is because the amount of fuel required for a non-flex fuel tune is much different for E85 than for regular gasoline. You will need to reflash your vehicle each time you switch between E85 and regular gasoline.

It is important to note that not all vehicles can be retuned for E85. If you are unsure, it is best to consult a professional.

Use an ethanol-compatible fuel system

To use an ethanol-compatible fuel system, you must first ensure that your vehicle is compatible with E85 fuel. This may involve making modifications to the fuel system, as E85 fuel has different properties to gasoline.

E85 fuel is a blend of gasoline and ethanol, or ethyl alcohol. In the USA, it is typically made from corn biomass, but it can also be derived from other plant materials and renewable sources. E85 contains up to 85% ethanol, while other common blends include E50, E15, and E10.

One important consideration when using E85 fuel is its impact on the fuel system. Ethanol is somewhat corrosive, so it is recommended that the fuel system be compatible with methanol to ensure its longevity. This includes the fuel pump, fuel lines, injectors or carburetors, fuel tank, and fittings. Anodized aluminum fittings are usually compatible.

Additionally, because ethanol has a higher stoichiometric rating than gasoline, the fuel pump, lines, and injectors will need to be able to flow at least 30% more fuel. Upgrading these components is essential to ensure the vehicle can handle the increased fuel demand when using E85.

It is also crucial to retune the vehicle to run with larger fuel injectors and adjust to the new fuel demand. Flex fuel vehicles have an ethanol sensor that allows the ECU to adjust accordingly, but non-flex fuel vehicles will need to be manually tuned. Failing to do so can result in serious engine damage.

By following these steps and ensuring compatibility with E85 fuel, you can safely and effectively use an ethanol-compatible fuel system in your vehicle.

Upgrade your fuel pressure regulator

Upgrading your fuel pressure regulator (FPR) is a crucial step when converting your vehicle to E85 fuel. The FPR plays a vital role in ensuring the engine receives the required amount of fuel at the correct pressure. Here are some detailed instructions and considerations for upgrading your FPR when switching to E85:

Selecting the Right FPR

It is essential to choose an FPR specifically designed for use with E85 fuel. E85 is an ethanol-based fuel with distinct properties from gasoline, so a compatible FPR is necessary for optimal performance and safety. Look for FPRs that are recommended for E85 conversions, such as those from Aeromotive or EFI Hardware. These FPRs are designed to handle the unique characteristics of E85 fuel and ensure proper fuel delivery.

Installation Process

Upgrading your FPR typically involves the following steps:

• Disconnect the old FPR: Start by locating the FPR in your engine bay and carefully disconnecting the fuel lines and electrical connectors attached to it. Make sure to relieve the fuel system pressure before removing any fuel lines to avoid spills or accidents.
• Install the new FPR: Choose an appropriate location for the new FPR, ensuring it is securely mounted and accessible for future adjustments. Connect the fuel lines and electrical connectors according to the manufacturer's instructions.
• Test the system: Once the new FPR is installed, test the fuel system for leaks and ensure that the fuel pressure is within the specified range for E85 fuel. Adjust the FPR as needed to achieve the correct fuel pressure.

Considerations

• Fuel Compatibility: Ensure that the FPR is compatible with E85 fuel. Some FPRs are designed specifically for gasoline or other types of fuel, so choosing one rated for E85 is crucial.
• Fuel Pressure Range: Verify that the FPR can handle the fuel pressure requirements of your engine when running on E85. E85 may require higher fuel pressure than gasoline, so ensure the FPR can accommodate this.
• Ease of Adjustment: Look for an FPR that is easy to adjust. You may need to fine-tune the fuel pressure after installation to ensure optimal engine performance with E85.
• Durability: Opt for a high-quality, durable FPR to ensure longevity and reliability. Ethanol can be corrosive, so choosing a regulator made from compatible materials is essential.

Upgrading your FPR is a vital step in converting your vehicle to E85 fuel. By selecting a suitable FPR and carefully installing it, you can ensure that your engine receives the correct fuel pressure and volume for efficient and safe operation with E85.

Frequently asked questions