BMW’s muscular coupe combines a thundering 390kW, 750Nm twin-turbocharged V8 with refinement, sophistication and entertaining dynamics. It’s a worthy flagship, at least until the M8 arrives

Hether called a 6- or 8-Series, since the mid 1970s, the BMW range has always been crowned by a fat sled of a coupe. The shark-nosed E24 6-Series started the sequence in 1976 and served as BMW’s flagship sports coupe through until 1989 when it was replaced by the first-generation 8-Series (the E31). After a decade, the 8 nameplate was parked and following a hiatus of a few years, two more generations of 6-Series topped BMW’s model line up. After that very brief history lesson, we find ourselves at the second-generation 8-Series, the G15.

The M850i xDrive tops the new-generation range, at least until the M8 launches. The new model is broad and low, possessed of a powerful athleticism. What’s not immediately apparent is that the new car is smaller than the 6-Series that it effectively replaces. The G15 sits on a wheelbase that’s 33mm shorter than the G32 6-Series and is 43mm shorter in overall length.

Behind the enormous kidney grille is BMW’s twin-turbocharged 4.4-litre V8. Here it produces 390kW at 5500rpm and a very stout 750Nm from just 1800 revs. Depending upon the drive mode that you’ve selected, the engine is demure or demonic. As the specs suggest, there’s ample urge from just off idle, but the throttle calibration and partnership with the eight-speed torque converter auto, means that the big BMW is super smooth mooching around at low speed. In fact, its low-speed civility is a match for luxury sedans costing considerably more than the M850i’s $272,900 ask.

Dial up sport mode (or sport plus) and start getting deeper into the throttle travel and the twin-turbo V8 hits hard through the mid range. When you’re driving quicker, the torque converter’s more relaxed nature doesn’t fire through shifts as crisply as a dual-clutch would. The relative tardiness of the gearbox (and we’re talking fractions of a second here) is most obvious when you demand a downshift via the left-hand paddle. There’s just enough of a pause for your brain to register and for your toe to dig a little deeper into the brake pedal travel to counter act the delay in engine braking. But these are minor complaints and amount to the smallest of chinks in an otherwise impressive dynamic armour.

The steering never over burdens you with information, but the overall driving experience is greatly enhanced by the rear-steering system. For a car that weighs a chunky 1890kg, the rear-steering endows the M850i with an agility that is welcome but unexpected. In sport or, especially, sport plus mode, the BMW corners flat and fast, but retains much of its exemplary low-speed ride quality. This combination of composure and accuracy takes some beating and the M850i can cover ground at a blistering rate.

The 4.4-litre twin-turbo engine is a real monster, thundering through its mid-range with a strength and aural urgency that suggests a much larger capacity. Where the upcoming M8 goes to from here is an enticing prospect.

Of course, the all-wheel-drive system plays a part as well, and despite sometimes wet roads, the M850i remained hooked up at all times. Provocatively large throttle applications from low speed were shrugged off by the all-wheel-drive traction and rapidly turned into forward momentum.

BMW isn’t shy about which rivals it believes the new 8-Series goes up against, naming everything from the $374,995 Aston Martin DB11 V8, to the $372,900 Mercedes-AMG S63 Coupe. Even the $422,600 Bentley Continental GT was mentioned as a possible contender. The BMW’s big ace in those comparisons is its $272,900 starting price, but that’s not the only thing in its favour. Dynamically, it’s at least as entertaining as the Mercedes-AMG and Aston, and ahead of the Bentley. It’d take back-to-back testing to confirm, but the ride quality and refinement is arguably better than these exalted rivals. It’s also quicker than the Aston and not far off matching the more powerful AMG and Bentley. Of course, the BMW roundel struggles against the winged glamour of the Bentley and Aston badges and the M850i’s interior isn’t quite a match for that of the Bentley or Mercedes.

Changing the badge on the boot hasn’t changed the fundamental philosophy of BMW’s range-topping coupe (and convertible). However, there’s no debating that this is a significantly better gadget than the one it replaces. The new M850i has real road presence, a fine interior, extraordinary refinement and entertaining dynamics. Jesse Taylor

Engine V8, 4395cc
Power 390kW @ 5500rpm
Torque 750Nm @ 1800rpm
Weight 1890kg (206kW/tonne)
0-100km/h 3.7sec
Top speed 250km/h
Basic price $272,900