It’s a rare privilege to be invited to drive a car that’s still in development and recently that privilege saw us behind the wheel of BMW’s M850i xDrive Coupe, a car that majors on its chassis technology. It’s the range-topper of BMW’s new flagship range and is launched this June.

Engine, transmission and 0-100 time
Power comes from a much-revised version of the established 4.4-litre twin-turbo V8. This features new turbos, new piston and cylinder bore coatings and runs higher fuel pressure for better ignition. Both efficiency and power benefit, with power rising to 390kW (up from 340) and torque rising to 750Nm (up from 650) from just 1800rpm. The higher-capacity eight-speed ZF auto has a greater scope, with its lowest ratios being shorter and its highest ratios being longer. As yet, there are no official performance figures, but with all-wheel drive, over 370kW and a weight of around 1900kg, a sub-4sec 0-100km/h time looks probable.

> BMW M5 review

Technical highlights
Where to start? The potent drivetrain connects to a development of the familiar BMW xDrive all-wheel-drive system – as opposed to the new M5’s four- or two-wheel-drive system. To this has been added adaptive damping and an electronically controlled rear differential (e-diff) to finely manage traction across the rear axle, and help turn-in and stability. Then there’s rear-steer, which counter-steers the rear wheels by a visible 3degs on tight turns and to help on corner turn-in, before parallel steering to stabilise things, which it also does at speed.

Optionally – and it’s the only chassis option offered; even the wheel size is fixed at 20-inch – you can have active anti-roll bars. To quote 8-series line manager Markus Flasch: ‘We know what is the optimum.’

BMW

What’s it like to drive?
The lockable car cover comes off to reveal a camo-wrapped coupe that appears big and sleek, with a rear side window line that has a hint of previous coupes. The interior is draped with cloth to hide any shape and detail, but we’re allowed to reveal the instruments and seats (sporty looking but generously cut and comfortable). The rear seats are for small children only.

> BMW M2 Competition

The V8 fires and settles to a traditional, deep, burbly V8 idle, as opposed to the M5’s lighter, flat-plane crank thrum, and once moving, the note melts away. The steering is rather light in town but gains weight from around 30km/h, though once onto Welsh A-roads, what impresses is the remarkable ride quality. We know these roads and how tricky these surfaces are, but the M850i is untroubled, soaking up the detail and maintaining superb body control on the bigger bumps, too.

It gets better. The road tightens and twists and the 8-series turns cleanly and willingly; body roll is limited, as is tail squat when the torque of the V8 is unleashed, yet despite the positive effects of the systems, the feeling from behind the wheel is simply that this is a very well sorted car. Which it is; to get all the systems to work in harmony, yet for none of them to be apparent, is a great achievement. And it steers precisely, too.

BMW

Our route takes in all the best and the most challenging roads in north Wales and the M850i is never wrong-footed. A reminder of how deceptively fast it is comes at a crest on a favourite road when the car takes good air… and lands with the composure of an Impreza. Refinement is a strong suit, too – there are no clonks or bangs as the suspension does its stuff on the most challenging surfaces.

> Mercedes-AMG S 63 Coupe

It doesn’t have the steering feel it deserves, though. I craved feedback and connection feel and without them never felt like turning off the traction aids to delve further, though I think that’s partly an intuitive recognition that it’s a heavy car, too – about 1900kg seems a good guess. Maybe BMW is saving outright sportiness for the M8…

John Barker