E85 is the ethanol blend consisting of as much as 85% of the gasoline content being ethanol, and not all fuel pumps can manage that. Because ethanol is more corrosive and has an affinity for water—resulting in rust and corrosion in the fuel system—E85 presents unique problems. Standard fuel pumps which are made for gasoline will not hold up find if high levels of Ethanol are used on a regular basis and this can cut pump efficiency and lifespan by 20-30% or more.
E85 compatible fuel pumps are often made of different materials like stainless steel and use E85 safe rubber seals and hoses, etc. These materials avert rust and deal with the characteristics of ethanol so that the pump is capable of doing and structurally sound. Many high-performance fuel pumps, such as those from Walbro and Bosch, state their E85 compatibility and use ethanol resistant materials that are less susceptible to the chemical attack potential of ethanol and achieve reliable operation with minimal wear.
E85 also has different fuel pressure and flow requirements. Ethanol has about 30% less energy in it than gasoline, which means E85 engines need more fuel to produce the same power resulting in 20-25% greater fuel pump demand. These elevated flow rates, which in performance vehicles can exceed 300 liters per hour, are what an E85-ready pump is designed to deliver, thereby providing sufficient fuel under maximum demand levels without overloading the pump.
For the owners that want to run E85 in the vehicle, it is imperative that the entire fuel system including the Fuel Pump is rated for ethanol. This compatibility not only maintains pump efficiency but also increases its lifespan because it helps prevent clogs, reduction in performance or premature failure caused by ethanol-blended fuels in non-compatible pumps.