The biggest difference, however, is the additional electric motor. Instead of one motor driving the rear axle, as found in the E-tron 55, there are two in the E-tron S: one for each wheel, à la Polestar 1, and each with its own single-speed gearbox.
This paves the way for ultra-precise torque-vectoring with, in Audi’s words, a high level of transverse dynamics. Or, in our words, improbably big skids if the car is in Dynamic driving mode with the stability control system set to Sport or, better still, entirely off.
Audi claims this system can distribute torque in a quarter of the time needed by any mechanical counterpart, such as the Sport differential in the new RS6 Avant, and during cornering can feed up to 162lb ft more torque to the outside wheel than the inside – far more than the 10% difference possible with the clutched Sport differential.
Furthermore, the electric torque vectoring system isn’t finally spurred into action only at the very limit of grip, and then with no true control over which direction torque is sent, as is the case with a regular limited-slip differential. In theory, the satisfying sensations of apportioning torque to the outside rear wheel can therefore be felt by the driver at any time.
The front axle is more conventional, with nothing more complicated than brake-based torque vectoring, but the long and short of it is that this tri-motor set-up, combined with Audi’s central control unit, can replicate the functions of the Sport, limited-slip and Torsen differentials, only faster-acting and all of the time. Issigonis would no doubt be impressed.
Meanwhile, total power for the E-tron S is up from 403bhp to 496bhp, with the larger front motor (the same as can be found in the tail of the E-tron 55) accounting for 201bhp and the two shorter rear motors, which are cradled back to back within the subframe, together making 354bhp. Total torque is an outstanding 718lb ft, with 456lb ft of that reserved for the rear axle.
Our chance to test this driveline came at Audi’s facility in Neuburg, near Munich. This is where its racing machines – including the R8 LMS GT2 and previous LMP1 cars – are shaken down for the first time, hence the generous grass and asphalt runoff (although this could equally be for the benefit of visiting journalists).
Unsurprisingly, even the colossal torque of three electric motors meets its match with a car that weighs more than 2500kg before you’ve even factored in passengers. So while the E-tron S gets off the mark briskly, from then on it feels no more than Volkswagen Golf R quick. However, what you do genuinely notice is the subtle rear torque bias during lightly committed driving, because from the moment you turn the wheel, the front axle mainly devotes itself to brake vectoring rather than propulsion and the rear axle’s torque vectoring simultaneously comes into play.