2018 Audi A8 to be built around lightweight spaceframe

The next Audi A8 sedan will use a complex blend of four materials in its construction to save as much weight as possible, but according to reports that won’t stop it being heavier than the current model.

Audi has revealed the body of its latest Mercedes S-Class and BMW 7-series rival, which is due to be unveiled on July 11, will rely on more than the traditional aluminium for weight saving and structural rigidity of its spaceframe.

High strength steel goes into areas mainly around the passenger cell, magnesium is used for components such as the suspension strut brace, and a carbon fibre-reinforced plastic panel makes up the rear of the cabin.

While Audi is claiming the new A8 is “an innovation driver in automotive lightweight design” German magazine Auto Motor und Sport says it will actually be heavier with the body in white weighing in at 282kg compared with 231kg for the current model.

That’s partly because the new A8 has had to be engineered to accommodate batteries for electrified versions and secure them in a crash, and increasing safety standards and the need for differing load paths in impacts has also added to complexity and weight.

2

New production techniques such as crimping the forward aluminium structure to steel components of the safety cell has resulted in slimmer A-pillars which Audi says has increased the door openings by 16mm and improved viewing angles by five degrees.

The A8 will likely use variations on the current engines ranging from diesels right up to the Bentley Bentayga’s W12 turbo, and Porsche’s new 4.0-litre turbo V8 is also in the mix.

With a 48-volt electrical system the A8 should also use electric turbochargers, probably for diesel versions.

While Audi and Porsche have jointly announced a new plan for sharing some vehicle architecture, it seems the A8 is based on the Q7’s MLB platform, not the Panamera’s sportier MSB architecture that will also underpin the next Bentley Continental.

MLB seems also to be the basis for the upcoming A9 coupe and Q8 crossover.

The Porsche/Audi collusion, which in the past has seen shared platforms such as the Q5 and Macan has been ramped up with the companies putting together a plan that reaches forward as far as 2025.

While Audi says “the focus is on joint development of shared vehicle architectures, modules and components” specifics about actual vehicles have not been released. But reports abound about Porsche’s modular sports car platform that can be used for rear-engined (i.e. 911) applications or mid-engined sports cars such as the Cayman, Boxster and Audi R8.