Audi is developing its next RS6 with a new twin-turbocharged V8 engine to give it substantially more firepower in its fight against the BMW M5 and Mercedes-AMG E63.

The new RS6 is due to make its debut at the 2019 Frankfurt motor show and will be built alongside the technically related RS7 at Audi’s Neckarsulm plant in Germany.

Like its bigger brother, the RS6 will pack a twin- turbocharged 4.0-litre V8 petrol unit, as used by the Porsche Panamera Turbo and Lamborghini Urus, to offer around 605bhp. That’s the same power output quoted for the limited-volume RS6 Avant Plus and 43bhp more than the previous regular RS6. The new engine is also said to deliver an extra 37lb ft, at 590lb ft.

By comparison, the M5 offers 600bhp and 553lb ft, and the most powerful version of the E63, the S, delivers 604bhp and 627lb ft.

Performance behemoth sheds two cylinders. Is that progress for the mighty Audi RS6?

Drive for the RS6 will be sent to all four wheels via an eight-speed torque-converter automatic gearbox and traditional Torsen torque-sensing quattro system.

The new RS6 is also set to have a near 80kg reduction in kerb weight largely thanks to the use of a second-generation MLB structure. As a result, it looks good for a 0-62mph time of around 3.6sec – 0.1sec quicker than the time quoted for the RS6 Plus. Refinements in aerodynamic efficiency are also set to give an incremental rise in top speed to 193mph.

The RS6 will arrive after the fifth-generation S6, which is also due in 2019 in both saloon and estate forms. The new S6 will swap its predecessor’s 4.0-litre V8 motor for a twin- turbocharged 2.9-litre V6, which is both lighter and more potent. It’s expected to deliver in excess of 450bhp and 406lb ft via an eight-speed automatic gearbox and quattro four-wheel drive.