1957 GM Fuel Injection, Fuel Curve

Time Capsule, GM’s 1957 Fuel Injected Chevy V8

Today, fuel injection is as common as cup holders and airbags, another take-it-for-granted advance that makes the modern automobile fuel efficient, environmentally clean, and easy to drive. There’s a reason that in the mid-1980s fuel injection knocked carburetors’ off the top rung of the fuel supply pecking order – it works. Heck, even NASCAR finally got the message (three long decades after production cars abandoned accelerator pumps and float bowls).

Fuel injection isn’t new. Inventors of the internal combustion engine began toying with the concept in the late 1890s, and by the 1920s fuel injection had become common in diesel truck engines. During WW1 and WW2, aircraft engines employed mechanical FI, as it was less sensitive to g-forces and changes in altitude.

By the 1950s, fuel injection began drawing serious attention from automobile designers, looking to adapt the aforementioned aviation setups. Hot rodders and land speed record chasers also tried with such systems, although they worked best at wide-open throttle. Then again, who needs stop-and-start drivability on the salt flats?

1957 Fuel Injection Chevy, Fuel Curve

Mercedes-Benz was the first auto maker to embrace mechanical fuel injection for cars, using a design developed by fellow Germany company, Bosch. In 1955, Mercedes-Benz outfitted a 300SLR Grand Prix car with a Bosch direct-injected aircraft engine. Yes, performance was outstanding! F1 ace Stirling Moss steered the 300SLR to victory in the demanding Mille Miglia 1000-mile endurance race.

1957 Fuel Injected Chevy, Fuel Curve

It was during this period that General Motors’ Chevrolet Division one upped its European rivals by offering the 1957 Corvette with a mechanically fuel-injected 283-c.i. small-block, a dramatic breakthrough for a domestic car maker. The Rochester Ram-Jet FI-equipped V8 created unprecedented horsepower per cubic inch of displacement. Without question, it was the most advanced powerplant on the market.

1957 Fuel Injected Chevy, Fuel Curve

Let a Chevrolet advertisement explain: “In American automobile engineering, the milestone is this: one horsepower from every cubic inch of engine displacement! Chevrolet is the first American production car to achieve this goal…with fuel injection and 10.5 to 1 compression ratio, we pulled 283 h.p. naturally, we’re proud.”

That industry-leading horsepower created industry-leading performance. Road & Track editors clocked the ‘Vette covering zero-to-60 in 5.7 seconds, two seconds faster than a Mercedes SL; the quarter-mile took only 14.3 seconds. It delivered drivability no carburetor could match: smooth, and fault-free running from a 900 rpm idle and all the way to a raucous 7,000 rpm. And fuel mileage? A frugal 20 miles per gallon (at a time gas was a 25 cents a gallon).

1957 Fuel Injected Chevy, Fuel Curve

1957 Fuel Injected Chevy, Fuel Curve

So, how did the 1957 Fuel Injected Chevy V8 work? Super Chevy magazine published an excellent description of the system:
“Rochester’s fuel injection system consists of three main components: the intake manifold/plenum (also know as the “dog house”), the fuel meter, and the air meter. The intake manifold/plenum is the largest and most visible of the components. There are two pieces to the manifold, a base plate, which doubles as a valley cover (and for the injector nozzles), and the actual plenum. The plenum’s job is to distribute air to the cylinders and serve as a mount for the fuel meter and air meter.

1957 Fuel Injected Chevy, Fuel Curve

Rochester’s engineers mounted the fuel meter to the right side of the plenum. This small rectangular component contains a large fuel reservoir with a conventional float, needle, and seat, and a positive displacement high-pressure pump. A flex cable attached to the distributor drives this pump. It runs at half engine speed and pressures vary from 7.2 psi at idle to 530 psi at 6,000 engine rpm. The fuel from this pump is delivered directly to the nozzles.

1957 Fuel Injected Chevy, Fuel Curve

The air meter is the third major component of the Rochester fuel injection system. It is mounted on the left side of the plenum. The air meter measures, controls, and delivers the air used in combustion. Its three main components are the throttle valve, the diffuser cone, and the air meter body, which contains the Venturi.”

Chevrolet offered the Ram-Jet system on Corvettes through 1965. It also could be special ordered on family sedans like the 1957 Chevy Bel Air as well. All that performance didn’t come cheap; it was a $550 option. Some Bowtie aficionados claim the small-block Chevy hit its apogee in ‘65 with the potent Ram-Jet injected 327 that pumped out a tire-melting 375 horsepower.

Sadly, the introduction of the Chevy big-block saw a return to carburetors, which ruled the day until the mid-1980s, when more advanced electronic fuel injection systems were developed as a means to hit government mandated emissions and fuel economy standards. Today, only old-school hot rodders cling to the carburetor.

1957 Fuel Injected Chevy, Fuel Curve

But in 1957, Chevrolet gave us motorhead’s a 25-year peak into the future.

Gary Medley has been a friend, ally and contributor to the performance community for decades. His interest in cars and journalism was pretty much a genetic imperative, as he is the son of Tom Medley, creator of Stroker McGurk. Medley’s own career path has traveled from the halls of Petersen Publishing to PR director for an Indy Car race to pitching tight-fitting Italian-made cycling shorts and countless other forms of high-speed life. Living between two volcanoes in Hood River, Oregon, Medley will be a regular Fuel Curve contributor when he’s not working to sustain his father’s legacy.