CORNER ONE: GET ON the throttle early at the apex, a few degrees of slip-angle from the rear, an almost undetectable squirm from the nose, an easing of the steering angle but little more. Slingshot acceleration. Smirk. Yeah, that’s quick.
Corner two: on the throttle early again, the fabulous sensation of a generously loaded supermarket trolley arcing into a drift around the hairpin of the condiments aisle: smoking Michelins. This is the same car. A clever car. They call it ‘two cars in one’.
They also use the word ‘inevitable’. ‘They’ being BMW M boss Frank van Meel and vice president of engineering Dirk Hacker, who are discussing one key fact about the new M5: it’s four-wheel drive. While it’s probably true that BMW can no longer resist the call from certain markets to power both axles, it’s the ongoing power-race against rivals that means deploying such prodigious performance through only the rear wheels has become increasingly unrealistic. Yet BMW, much like AMG with its new E63, has gone all-wheels-driven in its own unique way. The M5s that await us at BMW’s Miramas testing facility, not far from Marseille, are scruffy prototypes disguised with camo-swirls.
We will henceforth know this car as the F90 (M-cars now get their own type number), and while it doesn’t take much imagination to visualise the appearance of the finished article, harder to see are details such as the carbonfibre roof, the sunken centre-section of which continues the same styling motif as the bonnet. Under that bonnet lies a new generation of the familiar 4.4-litre twin-turbo V8, now with higher injection pressure, redesigned turbos and new cooling and oil-supply systems. It’s connected to an eight-speed Steptronic gearbox, not an M DCT twin-clutcher. A backwards step? Not at all, according to Hacker, who says the ultimate performance of the torque-converter is virtually indistinguishable from the twin-clutcher. He says it also holds an advantage when you’re just ambling around, doing what M5 drivers spend most of their time doing. For the same reason, the rear subframe is now attached to the body with bushes, not solidly mounted: M has tried to broaden this car’s appeal.
‘The car had to feel like a rear-wheel-drive car, but with a bit more traction,’ is van Meets succinct summary of the project brief. To achieve that, the engineers have adopted and developed existing components – the Active M diff from the M3/M4 and the transfer case from the M760i, which allows the power to be sent to both axles – and combined them with new software in a single, integrated control module. The transfer case, situated behind the M5’s gearbox, contains an electronically controlled clutch that sends power via a driveshaft to the differential at the rear. At that point, new carbonfibre clutch plates can distribute torque from zero up to 100 per cent on either side. Meanwhile, another driveshaft runs up to the front axle where there’s an open diff. For the first time, one ECU looks at every input: steering, throttle and braking from the driver, plus yaw, lateral, longitudinal and wheel-slip data from the car. It knows what’s happening before you do.
The cleverest part of the drive train is the centre diff, as its clutch can be anything from locked totally open, making the car rear-wheel drive, to completely closed, for a 50:50 power-split. M engineers don’t like to talk torque -split percentages because the M5 deals in much more subtle, precise metering to individual wheels. So sophisticated is the M5’s brain that the shuffling around of torque is said to be undetectable. The latest 5-series (the G30) is usefully lighter than the model it replaces, making it a good starting point for integrating around 60kg of additional drive shafts and differentials. Despite all that kit, the new F90 M5 is said to be lighter than its 1870kg F10 predecessor. Its wheels are 19 inchers as standard, with either Continental or Yokohama rubber. A 20-inch wheel shod with Michelin Pilot Sport 4s (or a Pirelli equivalent) will be an option.
All this means very little without an appreciation of the driving modes. As with so many modern cars, so much of the end result, and the labour spent during development, is attributable to the software. This new M5 has the usual Comfort, Sport and Sport+ modes that are individually selectable for the steering, throttle and dampers, and there are also three stages of tuning for the Drivelogic gearbox. However, it’s the Dynamic Stability Control (DSC) operation that really matters. With it fully on, the M5 is as four-wheel drive as it gets, although still with an emphasis on rear-driven entertainment.
Move to M Dynamic mode and that becomes ‘AWD Sport’. This, as you might expect, favours an even more rear-biased setup. Switch DSC off completely and you have a choice of three modes: 4WD, 4WD Sport and 2WD, all shown on the iDrive screen. The last of those is, you guessed it, entirely rear-wheel drive. Thankfully, you need not twiddle away through these modes in iDrive (or tap the hard keys on the centre console, which include one for a new sports exhaust) like a concert pianist, as they can be preset as ‘M1’ and ‘M2’ programs, accessible via buttons on the steering wheel. Out on track, the new M5 feels as brutally rapid as you might expect. BMW hints at a final output of around 620hp, with in excess of 700Nm of torque (the previous M5 was good for 600hp and 680Nm), but if that’s the case then these are particularly well-fed Bavarian horses of noble parentage.
This is also the first M5 to feature electric power-assistance for the steering, but it’s one of M’s better efforts and when lapping the wet, low-grip circuit it’s possible to get a real sense of the level of adhesion available. Mainly, though, it’s the car’s high-speed balance that impresses, and the Initial signs are that the new M5 is surprisingly agile for a car of its size. Play with the throttle mid-corner and the car’s attitude subtly shifts; change direction through the fast S-bends and it locks on to its new line with dogged enthusiasm and stays with you, resisting understeer keenly. However, it’s when you get back on the power that the M5 is really interesting.
Even in 4WD mode it always feels rear-driven, and if you’re greedy with the throttle on corner exit it’ll adopt a very neutral attitude. It’s not in the least bit intimidating, even with the DSC off. 4WD Sport mode will allow the rear to swing out given similar provocation but then pulls things straight with very little steering input required. And 2WD? A riot. Or a handful. It’s brilliant fun on a test track with someone else’s tyres, but if you just wanted to get home fast on a wet night In November… Well, at least now you can go for 4WD mode. Two cars in one, then, and a thorough re-imagining of the M5. We can’t wait to drive the finished car.