Porsche 928: the front-engined V8 grand tourer

The Porsche 928 is a grand touring car made from 1977 to 1995, across a single generation with an intermediate facelift. It is a 2+2 coupé with a rear hatchback, a water-cooled engine in front and rear-wheel drive, and it was Porsche’s first production car with a V8.

Porsche 928 at a glance

History of the Porsche 928

In the late 1960s Porsche was established as a maker of high-performance sports cars, and during the 1970s oil crisis its executives discussed adding a more economical luxury tourer. Managing director Ernst Fuhrmann argued for it, worried that the 911 was nearing the limits of its performance and that its sales in the mid-1970s suggested declining appeal. He pictured a range-topping grand tourer that combined sports coupé and luxury saloon, with a more spacious interior than the 911’s, and the American market, Porsche’s largest, pushed the design towards a front engine, a V8 and two real child seats in the back rather than the 911’s token ones. The aim was to compete with Mercedes-Benz and BMW.

Ferdinand Porsche ordered a production-feasible concept, and Fuhrmann began the design study in 1971. The 928 was Porsche’s first clean-sheet design for its own model: the 356 resembled the Beetle, the 911 grew out of the 356, the 914 was a joint venture and the 924 came from a cancelled Volkswagen and Audi project. Rear- and mid-engine layouts were considered, but emissions and noise equipment crammed into a small rear bay caused trouble, and the mid-engine layout left too little passenger space, so Porsche settled on a front engine and rear-wheel drive.

Engineers wanted a large-displacement engine. Early prototypes used a 5-litre V8 of 300 PS; a 4.6-litre 90-degree V10 derived from the Audi five-cylinder was discussed and rejected, partly for fear of rumours about a Volkswagen-based engine in a new 911 and partly to keep some distance from the Volkswagen Group. The production all-alloy M28 V8 had a bore spacing of 122 mm, thick aluminium cylinder barrels without steel liners and large water jackets, with spark plugs at the top of the head to keep the bonnet line low. The four-bolt main bearings were fed through grooves in the bottom of the block and carried in a large one-piece lower structure with a cast aluminium sump. The oil and water pumps were driven by the timing belt; in 1985 the double-overhead-camshaft engines adopted a hybrid system in which the belt drove only the exhaust camshafts and the intake camshafts were driven by chain, a layout later used by the 944 and by Audi and Volkswagen.

The first running prototypes used a single four-barrel carburettor, but production cars had the planned Bosch K-Jetronic injection. Concern about fuel prices led Fuhrmann to propose a 3.3-litre engine of 182 PS, which the engineers resisted; both sides settled on a 4.5-litre unit. The 928 went on sale in 1978 and won European Car of the Year, one of the few times the prize went to something other than a mass-produced family car. It ran to 1995 with a facelift in the middle of its life.

Design and features

• Front-mounted V8: Porsche’s first production V8, water-cooled and all-alloy.
• Grand touring comfort: a 2+2 cabin with a rear hatch and two usable child seats.
• In-house design: the first Porsche drawn from a clean sheet rather than developed from another car.
• Belt and chain camshaft drive: the 1985 layout that the 944 and later Volkswagen and Audi engines copied.

Porsche 928 versions

• 928 (1978–): the original 4.5-litre car.
• 928 S: the more powerful development.
• Facelift cars: the mid-life revision of the single generation.
• 928 GTS: the final, widest-engined version of the range.

The 928 was meant to take over from the Porsche 911, and its V8 was halved to make the four of the Porsche 944. More cars are in the Porsche collection.

Sources

• Porsche 928, English Wikipedia: conception, engine, layout, award