Don't Fill E85 Fuel In Your Car! Here’s Why

If you think that your E20 car/bike can run on E85 fuel as well, you are about to damage your beloved machine. E85 is a different fuel altogether and it takes extensive changes to make a vehicle run on it.

The move toward higher ethanol blends in petrol in India is happening whether we like it or not. And soon after E20, the government is now pushing for E85 compliant vehicles. And that is because your car or bike which is now running on E20 fuel, cannot run on E85. However, an E85 compliant vehicle can run on E20.

It cannot be used in a standard petrol engine without significant modification. Extensive changes are required for E85 vehicles to everything from the fuel tank and lines to the engine's electronic control unit and internal components. Here is an overview of how complex this transformation is.

What Is E85?

As the name suggests, E85 is a fuel blend consisting of around 85 percent ethanol and 15 percent petrol. For your reference, E20 fuel consists of around 20 percent ethanol and 80 percent petrol. It is very clear that the properties of E85 are fundamentally different from petrol. Ethanol contains less energy per litre than petrol, meaning an engine must burn more of it to produce the same amount of power. Hence, the fuel efficiency of any E85 vehicle will be lower than its E20 counterpart. 

Why E85 Cannot Work With E20 Vehicles

Every internal combustion engine requires a precise mixture of air and fuel for efficient combustion. While the ratio for E20 and E0 (Petrol) are relatively similar, E85 fuel fundamentally alters this required mixture. Also, because of these different combustion characteristics and fuel delivery needs, simply putting E85 in a E20 standard petrol engine will lead to poor performance, potential component damage, and engine starting problems. 

Ethanol also raises the risk of water contamination in the fuel system as it can absorb moisture from the surroundings and separate into water and fuel. Furthermore, its chemical makeup can be corrosive to certain rubbers, plastics, and metals used in older vehicles not designed for ethanol. Hence, running your E20 car or bike on E85 will surely cause damage. Now if you are looking for a more detailed explanation on what it takes to make an E85 compliant vehicle, read on. 

Changes Needed For E85

To make a vehicle E85-compliant, a series of hardware and software modifications are essential. And they are more than swapping different parts. The vehicle will need extensive modifications to address material compatibility, fuel delivery capacity, and engine management. It is a systematic process that touches nearly every part of the powertrain, ensuring reliability and proper functioning when running on high-ethanol-content fuel.

Fuel Line and Seal Upgrades

From the fuel tank, the fuel travels through lines, seals, and gaskets before it reaches the combustion chamber in the engine. Standard rubber hoses can degrade, swell, or crack when exposed to high concentrations of ethanol. These must be replaced with ethanol-resistant hoses. Similarly, all O-rings and gaskets throughout the fuel system must be swapped for compatible materials to prevent dangerous leaks.

Increase Fuel Delivery Capacity

Because E85 has a lower energy density, the engine needs significantly more fuel flow to maintain the correct air-fuel ratio. This requires upgrading the entire fuel delivery system and even its tuning. The fuel pump must be replaced with a higher-capacity unit capable of delivering greater volume at stable pressure. The fuel injectors also need to be swapped for larger ones that can flow more fuel into the combustion chamber.

Upgrade the Engine Control Unit (ECU)

The Engine Control Unit, or ECU, is the engine's brain. It controls fuel injection and ignition timing. For E85 use, the ECU's software must be completely remapped. For vehicles that will run on various blends like E20 to E85, a full flex-fuel software is required to ensure the engine gets the right amount of fuel and burns it with the right timing.

Add an Ethanol Content Sensor

A true flex-fuel vehicle uses an ethanol content sensor. This device is installed in the fuel line and continuously measures the exact percentage of ethanol in the fuel. It sends this information to the ECU in real-time, which then allows it to automatically adjust the fuel and ignition maps on the fly. This ensures the engine runs correctly whether the tank is filled with standard petrol, E20, E85, or any blend in between.

Cold Start Engineering

Ethanol does not vaporise as easily as petrol in cold temperatures to start the engine. This makes starting an engine on high-ethanol blends difficult in cool weather. E85-compliant vehicles require specific cold-start requirements programmed into the ECU. These heavily enrich the fuel mixture during startup and adjust idle control.

Emissions System Changes

Running on E85 also affects the vehicle's emissions control systems. The oxygen sensors that monitor the air-fuel ratio in the exhaust must be calibrated to work with ethanol's different combustion byproducts. Evaporative emissions systems, which manage fuel vapours, must also be compatible with ethanol to function correctly and meet regulatory standards.

E85 fuel is coming to India sooner than we expected but this one is a welcome change because it is an optional fuel. You decide to buy an E85 Flex-fuel car or a motorcycle and choose to fill it up with E85 fuel. Unlike E20 that was forced through, the consumer here remains in control of his choices. The Maruti WagonR and Suzuki Gixxer 250 Flex-fuel are already here and we expect more to follow. But whatever you do, please don't fill E85 in your E20 vehicle.