Development of the 928

by Phil Tong
Thanks to Phil for his kind permission to reproduce the article - www.928S4VR.com ©2000

Development of the 928 began in late 1971, pre-dating the 924 which was marketed before the 928.Porsche believed the venerable air-cooled 911 series could not possibly continue indefinitely given ever restricting regulations on noise, emissions and the crash-worthiness of rear-engined cars. Also, Porsche saw a need to fill in the horsepower driven and lucrative American market, which is where half of all new car sales were being made.

Power plants considered for the 928 included a V6 but luckily for 928 enthusiasts an all-aluminium 4.5ltr 16-valve SOHC V8 designed by Porsche became the chosen power plant. This engine also featured the world's longest (Gilmer-type and toothed) timing belt in a production vehicle - it measures nearly 7 feet if laid out.

Testing of the various drivetrain and suspension components were carried out in 911, Mercedes, Opel and Audi bodies. Porsche engineers went to great lengths during this process, as the donor cars sometimes had to be chopped, lengthened or widened to accommodate the 928 drivetrain & suspension. Later full-scale models and prototypes were given extreme testing in desert tests in Africa and ice tests Finland. Crash tests were dutifully recorded with the 928 fairing exceedingly well over and above the 5mph specs of the time.

The engineers were justifiably proud of their achievements, however, mid-way through the 928 development the first global gas crisis hit. In light of this, the Board of Directors now had to decide whether or not to continue on 'Projekt 928'. As we now know, development would forge ahead Porsche was willing to bet on the V8 platform to carry the marque into the future.

Design of the coachwork took place secretly behind curtains alongside 911 production. Numerous full-scale mock-ups of that glorious body and cockpit were created and tested for airflow. Nearing completion a rolling example was presented to the Board of Directors, who would ultimately make the final design approval. The selected body style is the original 928 introduced to the world at the Geneva car show of March 1977 and Project 928 had finally become the Porsche 928.

At it's unveiling the car stunned the world and was received to critical acclaim and controversy - the 928 was promptly awarded Car of the Year for it's many innovations such as the aluminium engine block and heads; and the 'Weissach axle" (named in honour of the Porsche R&D centre where it was created). The goal of the Weissach axle was to eliminate lift-throttle oversteer by allowing the rear suspension to actually adjust itself during cornering manoeuvres. The Weissach axle is one of the most noted features of the marque and has been adapted across the model line-up.

The 928 battery is attached to the rear transaxle to help dampen vibration. Thus equipped with a front-engine, rear transaxle layout the 928 has near perfect weight balance distribution of 51/49 front to rear.

Notable options: 1981 Competition package includes S type front and rear spoilers, sport seats. The main feature of the Euro S model, namely the 4.7 litre V8, would not make it's U.S. appearance until 1983. A special 928 Weissach edition was available and, similar to the 911 Weissach edition, featured champagne gold metallic paint, matching brushed gold alloy wheels, two-tone interior and the extremely collectible three-piece Porsche luggage set. Only 205 such cars were produced.

Production was carried out at the factory in Stuttgart - Zuffenhausen, side by side with the 911 cars thus eliminating any doubt as to the build quality of customer cars. It is interesting to note that even given the 928's pedigree, it has never attained the same reverence as the air-cooled Porsches.

Though thoroughly acknowledged by the press as the best GT car Porsche ever produced, it remains largely unappreciated except for those in the know, and those who have succumbed to it's unrelenting push toward top acceleration.