The 928 – Conception, Design, and Styling Changes

In Brief
The Porsche 928 is a grand tourer automobile sold by Porsche AG of Germany from 1978-1995, designed as a more luxurious yet still high performance alternative to the firm’s sporting mainstay, the durable 911 sports car.

In 1983 the 928S with a 4.7 litre 16 valve M28/19 engine and 5-speed manual transmission was the fastest car sold in North America, at 146 mph.

Conception
By the late 1960s, Porsche had changed significantly as a company, and executives including owner Ferdinand Porsche were playing with the idea of adding a luxury touring car to the line-up. Managing Director Ernst Fuhrmann was also pressuring Ferdinand to approve development of the new model in light of concerns that the current flagship model at the time, the 911, was quickly reaching its maximum potential where it could soon no longer be improved upon. Slumping sales of the 911 seemed to confirm that the model was approaching the end of its economic life cycle. Fuhrmann envisioned the new range-topping model as being the best possible combination of a sports coupe and a luxury sedan, something well equipped and comfortable enough to be easily driven over long distances that also had the power, poise and handling prowess necessary to be driven like a sports car. This set it apart from the 911, which was a pure sports car.

Ordered by Ferry Porsche to come up with a production-feasible concept for his new model, Fuhrmann initiated a design study in 1971, eventually taking from the process the final specs for the 928. Several drivetrain layouts were considered during early development, including rear and mid-engined designs, but most were dismissed because of technical and/or legislative difficulties. Having the engine, transmission, catalytic converter(s) and exhaust all cramped into a small rear engine bay made emission and noise control more difficult, something Porsche was already facing problems with on the 911 and wanted to avoid. After deciding that the mid-engine layout didn’t allow enough room in the passenger compartment, a front engine/rear wheel drive layout was chosen. Porsche also may have feared that the U.S. government would soon ban the sale of rear-engined cars in response to the consumer concern over safety problems with the rear-engined Chevrolet Corvair. The Corvair’s safety issues were famously detailed in the book Unsafe at Any Speed by consumer advocate Ralph Nader.

Porsche engineers wanted a large-displacement motor to power the 928, and prototype units were built with a 5.0 L V8 producing close to 300 hp (220 kW). Very early units used one four-barrel carburetor, which was eventually rejected in favor of Bosch’s K-Jetronic fuel injection system. When increasing concern within the company over the pricing and availability of fuel during the oil crisis of the 1970s became an issue of contention, smaller engines were considered in the interest of fuel economy. A push began for the development of a 3.3 L 180 hp (130 kW) powerplant they had drawn up specs for, but company engineers balked at this suggestion. Both sides finally settled on a 4.5 L, SOHC 16-valve V8 producing 240 PS (180 kW; 240 hp) (219 hp (163 kW) in North America), which they considered to have an acceptable compromise of performance and fuel economy.

The finished car debuted at the 1977 Geneva Motor Show before going on sale later that year as a 1978 model. Although it won early acclaim for its comfort and power, sales were slow. Base prices were much higher than that of the previous range-topping 911 model and the 928’s front-engined, water-cooled design put off many Porsche purists.

Fuhrmann’s replacement, Peter Schutz, decided that the models should be sold side by side, feeling that the 911 still had potential in the company’s line-up. Legislation against rear-engined vehicles also did not materialize. Although the 928 developed an avid fan following, it never sold in the numbers Fuhrmann had originally predicted and was discontinued in 1995.

Design
The 928 featured a large, front-mounted and water-cooled V8 engine driving the rear wheels. Originally displacing 4.5 L and featuring a single overhead camshaft design, it produced 219 hp (163 kW/222 PS) for the North American market and 240 PS (176 kW/237 hp) in other markets. Porsche upgraded the engine from mechanical to electronic fuel injection in 1980 for US models, although power remained the same. This design marked a major change in direction for Porsche (started with the introduction of the 924 in 1976), whose cars had until then used only rear- or mid-mounted air-cooled flat engines with four or six cylinders.

Porsche utilized a transaxle in the 928 to help achieve 50/50 front/rear weight distribution, aiding the car’s balance. Although it weighed more than the difficult-to-handle 911, its more neutral weight balance and higher power output gave it similar performance on the track. The 928 was regarded as the more relaxing car to drive at the time. It came with either a five-speed dog leg manual transmission, or a Mercedes-Benz-derived automatic transmission, originally with three speeds, with four speed from 1983 in North America and 1984 in other markets. More than half of production had the automatic transmission. Exact percentage of manual gearbox cars for entire production run is not known but its believed to be between 25 and 30%.

The body, styled by Wolfgang Möbius under guidance of Anatole Lapine, was mainly galvanized steel, but the doors, front fenders, hood, and roof were aluminum in order to make the car more lightweight. It had a substantial luggage area accessed via a large hatchback. The new polyurethane elastic bumpers were integrated into the nose and tail and covered in body-coloured plastic; an unusual feature for the time that aided the car visually and reduced its drag. Porsche opted not to offer a convertible variant but some aftermarket modifiers offer convertible conversions.

The 928 qualified as a 2+2, having two small seats in the rear. Both rear seats could be folded down to enlarge the luggage area, and both the front and rear seats had sun visors for occupants. The 928 was also the first vehicle in which the instrument cluster moved along with the adjustable steering wheel in order to maintain maximum instrument visibility.

The 928 included several other innovations such as the “Weissach Axle”, an early all-wheel steering system that provides passive rear-wheel steering while cornering, and an unsleeved, silicon alloy engine block made of aluminum, which reduced weight and provided a highly durable cylinder bore.

Porsche’s design and development efforts paid off during the 1978 European Car of the Year competition where the 928 won ahead of the BMW 7-series and the Ford Granada. The 928 is the only sports car so far to have won this competition, where the usual winners are mainstream hatchbacks and sedans/saloons from major European manufacturers. This is regarded as proof of how advanced the 928 was compared to its contemporaries.

Styling changes
Styling was the same from 1978 through 1979 and the body lacked both front and rear spoilers. From 1980 (1983 in North America) through 1986, front and rear spoilers were present on “S” models, rear spoilers were integrated into the hatch. From 1987 through 1995, the front spoiler is integrated into the nose and the rear spoiler became a separated wing rather than an integrated piece, and side skirts were added. The rear tail-light configuration was also different from previous versions. GTS model had wider rear fenders added to give more room for 9″ wide wheels.

Another easily noticeable visual difference between versions is the style of the rims. Early 928s had 15″ or 16″ “phone dial”-style rims, while most 1980s 928s had 16″ slotted “flat discs”, CSs, SEs and 1989 GTs had 16″ “Club Sport”, later GTs had 16″ “Design 90″ style which were also option on same period S4s, the GTS used two variations of the 17″ “CUP” rims.