Audi RS7 Sportback review – engine, gearbox and technical highlights
Ostensibly the engine and transmission are not dissimilar to those of the RS7 that came before, or indeed its key rivals
The RS7’s power comes from a revised version of Audi’s 4-litre, twin-turbocharged V8 TFSI unit, with cylinder-on-demand technology and a 48V mild-hybrid system to reduce fuel consumption.
In purely numeric terms the latest V8 is considerably more potent than before, with power now up to 592bhp, a gain of 39bhp, and torque at 590lb ft, around 74lb ft more than before. The engine is still attached to an eight-speed Tiptronic automatic transmission, with power sent to all four wheels through a mechanical centre diff and a locking ‘Sport differential’ at the rear axle to apportion drive. The standard torque split is 40:60 front-to-rear, while the centre diff can delegate up to 70 per cent of drive to the front wheels or 85 per cent to the rear if the situation calls for it.
The mild-hybrid technology – a glorified term for a belt-driven starter-alternator – is primarily there to reduce load on the powertrain, rather than providing any real assistance, but combined with cylinder-on-demand tech is good for fuel savings of around a fifth of a gallon every 62 miles.
Where Audi Sport’s work on the powertrain might seem a tad meek, the chassis’ overhaul has been far more extensive, starting with the two suspension options that quite dramatically change the way the RS7 feels on the road. The standard set-up is an air spring and adaptive damper combination, with adjustable ride heights depending on driver mode. It’s the optional Dynamic Ride Control system that is unique to these large RS Audis though, with a combination of hydraulically cross-linked dampers and steel coil springs quite dramatically changing the way the RS7 connects to the road surface.
The axles themselves are 80mm wider across both ends than the standard A7’s, so too are the suspension mounting points, while there are much stiffer bushes in the wheel carriers and upper suspension arms to control the sheer mass of the (optional) 22-inch wheels. The layout is actually quite simple, lacking the double-wishbone front suspension design of key rivals, but the set-up is so beefy it hardly seems to matter.
Also optional is a ceramic brake package pairing massive, 420mm front ceramic discs with ten-piston calipers; the rears have a only slightly smaller 380mm disc and six-piston combination. Because the RS7 comes with just two wheel sizes (21 or 22 inches), Audi Sport engineers have been more precise with their tuning, rather than compromising for everything from 17-inch winter wheels and tyres to massive 22-inch optional rims.
The four-wheel steering is also very clever. It’s fully 3D mapped so isn’t just programmed to give you a certain angle at certain speeds, as earlier systems did. Now its behaviour changes constantly depending on load, steering input, speed and a multitude of other factors. Depending on how you’re cornering, in other words, those rear wheels could be pointing in the same direction, or the opposite direction to the fronts – whatever is optimal for a given scenario.