In The Beginning
Performance fuel injection owes its success and popularity to a gent by the name of Stuart Hilborn. Stuart was first exposed to racing in the late 1930s when a friend took him to Muroc Dry Lake to take in some racing action. Needless to say, he was hooked right off the bat. Not long after, he built and raced an AV-8 Ford and also began constructing a streamliner that was unfortunately sidelined by the onset of World War II. Stuart took a break from racing and joined the Air Force. It was during that stint in the service that he began to draw up plans for his first mechanical fuel injector-starting construction on it in earnest after the war ended, developing a completely new and unknown principle now known as "constant flow" fuel injection. Despite skepticism from many so-called "experts" regarding its success, Stuart began racing with his fuel injector in 1947 and the success of his technological breakthrough earned Stuart the reputation as the "Father of Fuel Injection."

A lot of rodders were skeptical, yet the next year Howie Wilson piloted the then completed Hilborn streamliner beyond the 150-mph barrier thus effectively silencing his critics. While the car broke all records the streamliner's design was appreciated as a piece of art, as well. In April of that year it appeared on the cover of Hot Rod magazine and continued to campaign at the lake. Unfortunately though not long after, while on another speed run, the car flipped several times, putting both him in the hospital and the streamliner out of action. A while later Stuart took his injectors to Indy where they became an instant success. Bill Vokovich drove the "Fuel Injection Special" and though he crashed while leading after the 190th lap, Hilborn injection still got a First Place with a Troy Ruttman win. During the 1950s, 1960s and 1970s there were over 34 wins at the Indy 500 using Stuart's fuel injector. Today, it is used on many types of engines and all types of racing, including Sprint Cars, drag racing, super modified, off-road, tractor pulling, and motorcycles.

Over the years Hilborn mechanical fuel injection has been a boon to racing. Unfortunately not so for street-driven vehicles that must operate throughout the rpm range for extended periods rather than full-throttle blasts. That is until recently with the advent of modern computer controls and EFI. The basics behind EFI goes kind of like this: when you step on the gas pedal, the throttle valve opens up more, letting in more air. The electronic control unit (ECU) senses that the throttle valve has opened and increases the fuel rate in anticipation of more air entering the engine. Sensors monitor the mass of air entering the engine, as well as the amount of oxygen in the exhaust. The ECU uses this information to fine-tune the fuel delivery so that the air/fuel ratio is just right.

A fuel injector itself is really nothing but an electronically controlled valve. It is supplied with pressurized fuel by the fuel pump in your car, and it is capable of opening and closing many times per second. When the injector is energized, an electromagnet moves a plunger that opens the valve, allowing the pressurized fuel to squirt out through a tiny nozzle. The nozzle is designed to atomize the fuel, to make as fine a mist as possible so that it can burn easily and completely.

The amount of fuel supplied to the engine is determined by the amount of time the fuel injector stays open (Stuart's is called the pulse width, and it is also controlled by the ECU). Electronic injectors are mounted in the intake manifold so that they spray fuel directly at the intake valves. A pipe called a fuel rail supplies pressurized fuel to all of the injectors.

Operational benefits of a street-driven fuel-injected engine include smoother and more dependable engine response, easier and more dependable engine starting, better operation at extremely high or low ambient temperatures, reduced maintenance, and increased fuel efficiency.