PFI - Performance FI

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The PerformanceFI Story

The story of PerformanceFI began in the early 90's when Stew Prince met Mil Blair at the Bonneville Salt Flats and both realized they shared an interest in creating a fuel injection system that would increase the performance of V-Twin engines.

They spent years developing their vision of a turn-key EFI system for Harley Davidson motorcycles: compact, easy to install and use, and powerful. Early prototypes required electronics that were too big and complicated to be practical, taking up space the size of two saddle bags.

In the mean time, they created the Teresi Dyno-Drags, which continues to travel across the USA as the most popular attraction at every biker gathering where it appears.

Finally, in 2004, with new technology and backing from Steve Yetsky of Belt Drives Limited (BDL) and Joe Teresi of Easyriders, they built  what would eventually become the Pegasus Fuel Injection system.

When the Pegasus Fuel Injection system was finally rolled out in 2007, it quickly began receiving accolades from everyone who installed it on a Harley. That year, it won the prestigious “VTwin Expo Product of the Year" by Easyriders Magazine.

Stew and Mil never stop innovating and continue to improve the Pegasus system to make sure it remains the best V-Twin carburetor replacement solution on the Harley Davidson EFI market. They are always thinking of new ways to boost the performance of your Harley.

Stew Prince - Harley Davidson EFI

Stewart Prince is the founder and President of PerformanceFI. He is a Professor of Mechanical Engineering at California State University at Northridge where he has taught for 20 years, specializing in automotive engineering. In addition to teaching, he has served as a consultant to many different companies, including Aerodyne, Easyriders, and Performance Machine, and done research for the California Air Resources Board on automotive emissions.

Stew has been tearing machines apart--and sometimes putting them back together-- his whole life. During high school Stew worked at his uncle's gunsmith shop where he learned to run machines like lathes, mills, etc., and how mechanical things work. After high school he worked on an offshore drilling platform in the Gulf of Mexico in both the engine room and on the drill floor.

Stew has ridden motorcycles his whole life. While living in Venezuela, he had two Honda minitrails, a Honda 90 supersport, and a Benelli dirt bike. He bought a '65 Harley Panhead in 1978, tore it apart and rebuilt it (countless times). He hit the open road with it and his friends and rode all around the US southwest.

Stew designed his first electronic fuel injection system in 1982. He has designed many different ones since, including for his dissertation (Engine air control/drive by wire). He has designed various systems that have emphasized low emissions, power, or alternative fuels.

Stew created PerformanceFI in order to serve the Harley after market, bringing his professional automotive engineering background to V-Twin fuel injection.

Mil Blair - V Twin Harley Davidson aftermarket

Mil Blair (Research and Technical Support) doesn't have a straight answer when you ask him what he does for a living. "Inventor, backyard engineer, poor man's mechanic, sometimes know-it-all," but his most accurate answer is "I have fun." For a man who knows everybody who is anybody in the American motorcycle industry, his is a job description that captures not only the business, but also the culture, of motorcycles.

Mil got his first bike, a '47 Knucklehead, when he was eighteen years old living in Minnesota. In 1959 Mil and his buddy, Joe Teresi, left Minnesota winters behind and set out for Los Angeles with a Harley, a BSA, and $68 between them. After working for a record company they managed to start their own – building the actual plant from the ground up - but that was just a temporary diversion from their true love: motorcycles. In the meantime they drag-raced at Lion's drag strip from 1961-1965.

In 1967 Mil and Joe bought Psychedelic Choppers and turned it into a parts manufacturing company that eventually became Jammer Cycle Products. At the same time, with Lou Kinzey, they introduced Easyriders Magazine to the motorcycling world. While Mil maintained oversight of the manufacturing business, he also served as a one-man production machine, writing technical articles and arranging and conducting the photo shoots for both Easyriders and Jammer product catalogs.

For decades, Mil's business was the pleasure of owning and riding motorcycles. He attended every bike show, convention, and rodeo. He helped develop products and define trends. He tested products and rode bikes and met thousands of people who are now friends and colleagues.

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Read About Other Harley Riders' Experience with the Pegasus System

Check out this review of the Pegasus system by Easyriders Magazine

(Special thanks to Joe Teresi and Cathy Gibson at Paisano Publishing for providing a copy of this article. Note: this file is approximately 53MB and may take longer to download)