Audi says that the aluminium body of the new A8 weighs only 231 kilograms (509.27 lb), an important factor not only for fuel efficiency and lower emissions than with a comparatively sized steel body, but also for driving dynamics and stability. Audi estimates that in steel, the body would weigh about 323 kg (+40%).

Audi introduced the technology of the Audi Space Frame (ASF) into production in 1994, with the first A8 generation. Now, the luxury brand of the VW group is again using it in a more advanced form on the new A8.

Using 13 different aluminium alloys, Audi says that the frame of the ASF body comprises extruded sections and pressure die cast parts of aluminium; the aluminium panels – such as the roof panels and the side panels – are joined by friction connections. The material is used where necessary and always in a tailored configuration.

The combined weight of all the castings, most of which are made of advanced alloys, is three kilograms (6.61 lb) lighter than with the previous model.

The vacuum die cast components are used wherever high forces are induced locally and there is a need for versatility and design freedom. The A-pillar node is one such multifunctional component. It connects the longitudinal member, the windshield crossmember, the roof frame, the strut mount and the omega bracket in front of the footwell. Most of the 25 castings in the new A8 are manufactured using the high-precision vacuum casting process.

The roof arch is produced by hydroforming: the section is shaped by a liquid forced into it at high pressure. Its cross-section changes multiple times with smooth transitions over the 3.20 metre (10.50 ft) length.

Audi says that it has increased the strength of the higher-strength body components in the new A8 by as much as 25 percent, thereby reducing both material thickness and weight by up to 20 percent. This is due in part to a composite material for the aluminium sheets called a fusion alloy, which alone saves 6.5 kilograms (14.33 lb). Fifteen fusion panels are used for the load-bearing parts of the structure – the centre tunnel, the cross bracings in the floor, the windshield crossmember and in the area of the rear seats.

The total weight of the front and rear bumpers and the radiator grille declined by 300 grams compared to the previous model. The lower crossmember of the front end is made of a novel matrix of fibre reinforced plastic, reinforced by three aluminium panels embedded in it. Weighing 5.4 kilograms (11.90 lb), the component weighs 84 grams (0.19 lb) less than a solid aluminium solution and saves 2.3 kilograms (5.07 lb) over steel. Even the doors are lightweight, thanks to a new, fully integrated concept for incorporating the window frames.

The static torsional stiffness of the ASF body has increased by 25 percent compared with the predecessor. The dynamic torsional rigidity of the body improved 15 percent, while its lightweight quality – the relationship between weight, torsional stiffness and size – improved 20 percent.

Audi adds that the lightweight aluminium used in the body is also greener than steel with respect to CO2 emissions. Although it consumes more energy during primary production, its major weight advantage offsets this disadvantage after 50,000 kilometres (31,068.56 miles) of driving. When the vehicle reaches the end of its life, all of the aluminium components can be recycled using just a small amount of energy. The body of the new A8 now comprises 38 percent ecologically produced secondary aluminium.