BMW M5 Prototype 2018 Review - International

Although BMW hasn't told us everything about its 2018 M5 as yet, a quick glance at the approximate specifications won't raise any eyebrows.

It's powered by a development of the company's muscular 4.4-litre twin-turbocharged V8, as before. Power is said to be up 'a little' and it's now mated to the eight-speed Steptronic automatic transmission already seeing good service in the BMW X5 and X6 M models - replacing the fast, but sometimes clunky old seven-speed M DCT dual-clutch item in the M5.

Thanks to the new 'G30' 5 Series diet regime (and a very cool carbon fibre roof), the new M5 is said to be 'a little' lighter before, but the interior, even on the disguised prototype we're driving, is no stripped out environment, so the M5's remit is, as ever, to be a luxury car with a seriously naughty streak.

However, BMW M then let slip that the new M5 will cover the 0-100km/h sprint in 'less than 3.5 seconds'. That's about a second quicker than the old car, which can't quite be accounted for by a slight power increase, a little less weight and a slicker transmission.

No, that's thanks to the addition of four-wheel drive. Lifelong fans of rear-drive sports saloons will no doubt slam their phones down or punch their computer screens at the news, but hang in there guys, as it's not the bad news it sounds like it might be.

For starters, there's a 2WD mode that the driver can select whenever they want. Calmed down? Good, time to look at that 'M xDrive' system in a little more detail.

As you'd hope, it's rather different to any other xDrive BMW. To begin with, the electronically controlled Active M Differential is retained at the back, though it has been upgraded with carbon plates.

These, say the engineers, help give the driver better feedback and control. And having spent the day trying our best to go as sideways as possible in the new M5, we have to admit that it's far better at telling the driver where the limits are than the previous car was.

There's no twitchiness, no nervousness or guesswork, just smooth, easily read transition from grip to slip. As ever, that differential has the ability to send up to 100 per cent of the available torque to either rear wheel, which makes the M5 rotate in a deliciously agile manner.

Distributing the engine output between the open differential up front and that rear item is a centrally located transfer case, which houses an electromechanically activated multi-plate clutch.

That too can, depending on commands from a new central controller, send up to 100 per cent of the torque to either front or rear axles.

That controller integrates all the sub-systems to a 'feed forward' concept, where the torque split between ends of the car is not the target, but the result of the strategy, and BMW's engineers assure us that they were aiming for a car that feels as good to steer as any rear-drive M saloon in history.

However, their remit was also to make sure that the M5 can be used every day and on long journeys in comfort, so there are conflicting requirements at play.

To that end, there are even more driver settings than ever before. There's the standard Comfort, Sport, Sport Individual options of course, grouping all the sub-systems together, while the power steering (now an electrically assisted system that has a quicker ratio than the old car) assistance, damping, throttle response and transmission can all be altered to suit individually as well.

A chunky new steering wheel features more prominent M1 and M2 buttons to house your favourite group of settings and a large new gear selector has the three-mode Drivelogic adjuster integrated into it.

The Dynamic Stability Control (DSC) system also gets three settings - DSC on, M Dynamic Mode (MDM) selected by pressing the DSC button once, and DSC off, accessed by holding down the button until a warning pops up on the dashboard that basically translates into "you're on your own, mate".

The control of the M xDrive system is linked closely to all this. By default, with DSC on, the car is in 4WD mode. This is the M5 at its most restrained, allowing anyone jump in and drive safely at speed in pretty much any conditions.

You can't easily tell that there's power going to the front wheels, as the DSC smoothly intervenes before you get a chance to sense what's going on when the limits of grip are approached. The good news is that the M5 feels rear-drive, even in this guise, especially if you're not trying to drive particularly quickly.

When MDM mode is selected, so too is 4WD Sport, and the M5 feels much friskier and more willing to wag its tail by a few degrees for short amounts of time before the electronics step in to keep things neat and tidy.

At no stage is the car nervous, but it's undoubtedly more willing to allow the driver to play with the limits a little more. This is highly effective when you're just in a hurry and the conditions are less than ideal.

Keener drivers will, by default, reach to turn off the DSC system, as that allows them to then choose between 4WD, 4WD Sport and 2WD. On a streaming wet handing circuit we had the opportunity to push the M5 beyond its limits in all modes and they're remarkably different.

The 4WD setting is incredibly neutral, only allowing full on power slides if you provoke them, and then it pivots about the middle of the car with all four wheels more or less pointed the same way.

It takes a lot of space and commitment to get to that stage though, as the car is naturally just fast and far from wayward. More importantly, there's no push-on understeer unless you wrench the steering wheel into a turn awkwardly.

The 4WD Sport mode, with the DSC off, is sublime, and experienced drivers will probably use that most of the time on the public road, as it offers huge traction at all times, yet the real sensation that this is a rear-wheel drive car.

Even on a dry race track it was possible to drift the M5 sideways in this guise and the system cleverly doesn't fight with you the whole way, trying to pull the car out of the slide, instead working with you to make it smooth and highly enjoyable.

And last, but certainly not least, 2WD. This means over 600hp going through the rear wheels alone, remember, with no traction control to help you out.

The previous M5 could be a little unpredictable in how its traction broke loose, but the new one is so good at communicating its limits with the driver that there's no fear to be had from the 2WD mode for the more experienced, even in wet conditions.

The quicker steering and polished workings of the Active M Differential make it a cinch to play with at and way beyond the limits of traction and adhesion.

Clearly, very few actual buyers of these cars are likely to use all the modes or drive them as extremely as in our pictures, but they'll undoubtedly be glad that the M Division hasn't abandoned the M5's wicked streak in a bid to make it more appealing to more drivers.

And that's before we know the full story and get it together with its AMG-badged adversary. Should be quite the fight.

2018 BMW M5 pricing and specifications:
Price: $250,000 (estimate)
Engine: 4.4-litre V8 twin-turbocharged petrol
Output: 455kW/750Nm (estimate)
Transmission: Eight-speed automatic
Fuel: approx. 9.4L/100km
CO2: approx. 230g/km
Safety rating: Not tested