The Porsche faithful have never forgiven former engineer and board chairman Ernst Fuhrmann for perverting the brand's sports car purity with the 928. But, like the Cayenne and the Panamera, the 928 is a worthy Porsche family member that did its duty--keeping the company alive and kicking through turbulent times.
The 928 was conceived in 1971 as the car that would define Porsche's future. Stuttgart's fear was that mounting U.S. legislation might soon throttle its beloved 911. As the Nader era gained momentum, there was a real possibility that the high-strung, air-cooled, rear-engine Porsche might be declared verboten at the flick of a bureaucrat's pen. Forgive Fuhrmann for not knowing that the 911 was cruising placidly toward immortality.
According to Karl Ludvigsen's Porsche chronicle, Excellence Was Expected, Fuhrmann's crack engineering team needed only a few days to agree on the 928's key details. This first clean-sheet design in the company's history was also a sharp break from its past. The 928's front-mounted, liquid-cooled V-8 was the first large-displacement, mild-mannered engine to wear the Porsche crest. The cabin was larger and more luxuriously outfitted, with an eye toward trumping the BMW CS, the Jaguar XK-E, and the Mercedes-Benz SL. One link to the past was a rear-mounted transaxle to optimize packaging, weight, and balance concerns.
The 928's V-8 was designed with a relatively small 4.5-liter displacement to facilitate a low hoodline and to achieve respectable fuel economy. The die-cast aluminum engine block had a high silicon content to circumvent the need for cylinder liners. Although this scheme proved unsuccessful in the Chevrolet Vega, Porsche solved durability issues, and the same Alusil (aluminum-silicon) cylinders were fitted to 911 engines beginning in 1974. A lower-block girdle integrating five main-bearing caps with two longitudinal reinforcements provided rigid support for the forged-steel crankshaft.
Topped with belt-driven single overhead camshafts, an elaborate tuned-runner intake manifold, and Bosch K-Jetronic fuel injection, the 928's V-8 looked spectacular in comparison with today's plastic-shrouded engines. Porsche stylist Anatole Lapine added to the spectacle by suggesting a glossy white paint finish for the intake runners.
Chassis details included Porsche's first power rack-and-pinion steering, an unequal-length control-arm front suspension (versus the 911's struts), cost-effective coil springs (instead of torsion bars), and a clever compound pivot in each rear-suspension trailing member that provided stabilizing toe-in during deceleration. Although the last feature wasn't an original idea, Porsche made it seem like a technological breakthrough by dubbing the arrangement the Weissach axle. (Weissach, Germany, is the location of Porsche's development center.)