Flexible Fuel Vehicle Conversions

Related Information

Conventional gasoline vehicles can be converted to flexible fuel vehicles (FFVs), which run on E85 (a gasoline-ethanol blend containing 51% to 83% ethanol), gasoline, or any mixture of the two. FFVs are different from conventional gasoline vehicles because they have to accommodate the unique fuel properties of ethanol. Converting a conventional gasoline vehicle to a flex fuel vehicle requires extensive modifications throughout the fuel system and electronic engine-control system.

Any change to a vehicle or engine that could potentially affect exhaust or evaporative emissions requires certification with the appropriate air quality authority. Manufacturers must go through a certification process to ensure their systems will not have a negative effect on emissions. Emissions standards are fuel neutral, which means that the same emissions requirements apply no matter which fuel powers the engine or vehicle. Therefore, to comply with emissions standards, converted vehicles and engines must demonstrate that they meet the same emissions standards that the original equipment manufacturer vehicle met.

Certificate of Conformity

The U.S. Environmental Protection Agency (EPA) has a process by which manufacturers of conversion systems can obtain a Certificate of Conformity or tampering exemption for converted vehicles. The certification process involves EPA testing of converted vehicles prior to issuing the certificate or tampering exemption. Certification applies only to specific conversion systems in specific vehicle makes, models, and model years, not to the conversion system by itself. Using non-certified conversion systems is illegal and may affect warranties.

Fleet managers interested in a vehicle conversion should contact the manufacturer (or its authorized agent) holding the Certificate of Conformity for more information about availability and cost. A technician trained by the manufacturer or authorized agent should always perform the actual conversion, whether it is done at the manufacturer's facilities or elsewhere. It is the manufacturer's responsibility to ensure equipment is safe, durable, and meets the appropriate emissions standards.

To learn more about vehicle conversions, go to the AFDC's Conversions page or watch this MotorWeek video.

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