When designing the 928, which went into series production as of model year 1978, the focus was on lightweight construction. The doors, front wings and bonnet were therefore made from aluminum instead of sheet steel. Behind the plastic bumpers integrated in the body shape there were also aluminum profiles that could withstand a collision at up to 8 km/h (5 mph) without any damage.

The 928 had round, electrically operated pop-up headlights that were integrated in the wings. The rounded fastback was dominated by the large window of the rear lid.

The 928 models were powered by a water-cooled V8 engine with a 90° cylinder arrangement. The displacement of the power unit was increased from an initial 4.5 litres to 5.4 litres. Power was transmitted according to the transaxle principle.

To improve aerodynamics, the models were fitted with a front and rear spoiler from type 928 S (MY 1979) onwards.

The rear axle of the 928 was a completely new development. What made this double-wishbone suspension – also known as the Weissach axle – unique was its toe-in stabilising effect. This worked more or less as a passive rear-wheel steering, making a significant contribution to the active safety of the Gran Turismo.