To get an idea of just how chillingly effective the new BMW M5 is, imagine yourself tooling along a smooth, lightly undulating Spanish back road at around 50mph. Ahead is a line of seven cars – none of which appears eager to overtake – and a straight stretch of asphalt dotted with broken white lines. You begin to calculate how many cars it's possible to pick off before the crest in the distance. Perhaps three, maybe four, conceivably five…
In the end the sums don't matter, because the new M5 has no trouble swallowing all seven cars in one full-throttle, third-gear lunge, and remarkably there's still a good couple of hundred yards before those broken white lines meld into an unbroken lane divider. To say the new M5 is fast is perhaps stating the obvious.
Truth is, we knew the new M5 would be a bullet in a straight line, what with 10 percent more power and a vast 30 percent more torque than its predecessor. The surprise is just how fast it is in real-world terms. I can't think of a four-door sedan, past or present, offering such potent yet openly accessible performance.
Being the first M5 to eschew naturally aspirated power in favor of turbocharging, it is all too easy to point to the engine and say it makes all the difference. But the more you drive it, the more familiar you become with all the different drive programs, and the more time you take in tailoring the damping to suit the road, then the more obvious it becomes that the new engine is but part of the bigger picture. This is an M5 like no other, and it's better in just about every respect.
Central to the technical advances that BMW has made is the decision to supplant the naturally aspirated 5.0-liter V10 of the previous model with a twin-turbocharged 4.4-liter V8. The 90-degree unit, which is mounted 20mm lower in the engine bay than standard 5-series powerplants, is a development of the engine used in the X6M. However, there are sufficient differences between the two units – including the cylinder head, internal architecture and the induction and exhaust systems – to lead BMW M officials to describe the M5's engine as being new.
Key among these changes is the adoption of Valvetronic fully variable inlet and exhaust timing. The M5 also receives unique intercoolers and a new pair of Honeywell turbochargers that run a nominal 0.9bar of boost – or 0.1bar lower than that of the X6M's engine. The pistons have also been modified for lower reciprocating mass, which has allowed BMW to up the ignition cut-out point to a reasonably high (by turbocharged engine standards) 7200rpm, although it's still a good 950rpm lower than that of the old naturally aspirated engine it replaces. There's also a new electronic management system that is claimed to have more computing power than any existing system used by a series production BMW engine.
At 552hp, the new engine delivers 51hp more than the old M5's naturally aspirated engine. However, peak power is now delivered 1750rpm lower in the range, at 6000rpm. More telling, though, is the torque. It peaks a substantial 153lb ft higher than before, at 501lb ft, but it can be tapped a telling 4600rpm earlier, at 1500rpm – or just 700rpm beyond idle. These figures mean that the new M5 continues a long tradition in which each iteration becomes more powerful and has more torque than the model it replaces.
A further technical highlight is the adoption of a new 7-speed, dual-clutch automatic gearbox as standard. The Getrag-engineered unit replaces the 7-speed sequential manual of the old model, offering both fully automatic and manual modes. It channels drive to the rear wheels through a newly developed version of M division's electronically operated Active M differential that's capable of providing continuously variable lock-up to each of the rear wheels, while revised gearbox and final drive ratios take full advantage of the diesel-like torque loadings. The new gearbox also adopts the automatic stop-start and brake energy recuperation features seen on other BMWs.
Visually, the M5 is distinguished from its 5-series siblings by a limited set of exterior styling changes. It's a fairly subtle makeover, but that, says BMW, is exactly what M5 customers want. Up front, a deeper bumper carries huge cooling ducts, along with a reworked grille, newly contoured hood and more heavily flared wheel arches.
Other differences include wider door sills, wider rear arches, a small trunklid spoiler and a new rear bumper. The most effective visual change, though, is reserved for the chassis. With a 27mm wider front track and 38mm narrower rear track than the standard 5-series sedan, the new M5 possesses an alluringly squat stance that is made all the better by a 25mm reduction in ride height and a set of 19in. alloy wheels. But with a drag coefficient of just 0.33, it's not as slippery as the old car.
The subtle approach continues inside. On top of the usual M5 accoutrements – M sports seats, trims, heavily bound leather-rimmed steering wheel and unique instruments – there's a reworked center console housing a stubby gearlever that is surrounded by a series of buttons. These include the all-important M button that allows the driver to alter the settings of the steering, throttle, gearbox and stability control as well as a button to alter the stiffness of the dampers in three settings: Comfort, Sport and Sport Plus.
It's a business-like driving environment crammed with all the latest in passive safety features, although it leans heavily on the regular 5-series sedan and ultimately lacks the flair that a car with such towering performance should surely offer. There's an on-board computer, for example, but unlike rivals it doesn't offer a g-meter even as an option. No such concerns about its practicality, though. With a 74mm longer wheelbase than its predecessor, the M5 now offers more rear seat accommodation than before. And with 18.4 cubic feet of luggage capacity, it matches the old model for load-hauling ability.
And how it can haul. In real-world terms, the M5 is considerably faster than the car it replaces by dint of its more accessible performance. BMW claims 0-62mph in 4.4sec, but I won't be surprised to see independent tests better this. It certainly feels faster, and with its superb traction, heroic acceleration and rifle-action gearchange, the new M5 is able to sustain high speeds on roads that would have worried its more firmly sprung predecessor. Its in-gear qualities are something else again. In fourth, it'll run from 50mph to 75mph in 3.7sec, and just 8.6sec after it reaches 62mph it hits 124mph. Top speed is limited to 155mph, and there's an optional M Driver's Package to bump it up to a limited 190mph.
So it is fast. Fast enough to be a real threat to your license. But what really distinguishes the new M5 from every M5 that has gone before it is the enormous flexibility of its power delivery. Bury the throttle at anything beyond 1500rpm and it surges forward with immense force. Given the heady output, the tractability at low revs is staggering.
It's a vastly different driving experience from the old M5, whose performance relied heavily on your level of commitment to extract it. This new model is, for the most part, even more thrilling from behind the wheel. Yet it doesn't ask for any special favors. The performance is omnipresent and passing is truly effortless, helped in no uncertain part by the effectiveness of the new gearbox. I'm not sure how BMW has done it, but the shifts are racecar quick, accompanied by an alluring bark of exhaust on full-throttle upshifts and a hearty blip on downshifts.
The added flexibility does have its drawbacks, though. Chief among these is a curious lack of crescendo in its delivery. Because the torque is developed across such a wide rev range, the engine doesn't feel much stronger at 6000rpm – the point where peak power arrives – than it does down low. The shove is colossal, but it is also oddly constant. Among the many delights of the naturally aspirated engine in the old M5 was the way its intensity grew in line with the number of revs it was asked to carry. The new turbocharged unit is clearly more user-friendly but it lends nowhere near as much character, nor does it possess the rabid throttle response of the old M5.
The best part of the new M5, though, is not its outright pace but its agility. The overall feel is determined both by the damper mode chosen and by how willing the driver is to alter the stability control system, which offers three settings: default, MDM (M Driver Mode) and completely switched off – the last of which requires the button to be depressed for three seconds.
In default mode, there's a lot of intervention from the stability control, which has clearly been calibrated to provide a wide safety net. Switch it into MDM, though, and the handling instantly becomes much more fluid in nature. I was worried that the big engine and all of its ancillaries might make for a nose-heavy cornering feel, but I was wrong. The M5 feels wonderfully balanced and more neutral than the car it replaces. There's less initial push at the front on turn-in and grip is immense, but with all that torque on offer the M5 is a willing sideways companion when you switch the stability control off. There's always a sense of balance to the chassis and the breakaway is telegraphed with such clarity that it all but urges you to steer through corners on the throttle.
The aluminum-intensive underpinnings, with the uniquely arranged double wishbone front suspension and heavily modified multi-link rear end, offer superb body control. There is a moderate degree of lean as you guide the M5 into corners, but its actions are wonderfully progressive, thanks to terrific damping that ensures any movement remains within a tightly dictated range. Where it really impresses is in its ability to settle quickly when faced with crests and undulations, and there is sufficient give to ensure it doesn't fight the road.
There's also an impressive suppleness, thanks to the variable damping. Despite the lack of compliancy in the tires' sidewalls, the underpinnings manage to retain a good deal of composure, seldom allowing anything more than a sharp ripple to upset progress. In this respect, it's much calmer and more relaxed as speeds rise than its predecessor.
It's only the steering that disappoints slightly. The speed-sensitive hydraulic steering, geared at 2.7 turns lock to lock, is an improvement on the electro-mechanical arrangement used by standard 5-series models, offering a more convincing feel and greater levels of feedback. But it possesses a lifeless feel around the straight-ahead. Once you've negotiated this, though, it's much more alert.
If there's one thing you do in the not-too-distant future, make sure you sample the new M5 in one way or another. In many respects it's a landmark car, and the fast car competition – Audi, Cadillac, Jaguar, and Mercedes-Benz among them – will be scratching their heads as they attempt to come up with a reply. The sheer potency and accessibility of the new engine alleviates any lingering doubts about M division's decision to turn a 25-year tradition of naturally aspirated engines for the M5 on its head.
However, the engine is only one component in a complete and utterly compelling package. What also makes this car so special is its overall agility, breadth of ride quality, superb refinement, practicality and great quality. With a 21-gallon fuel tank and combined cycle fuel consumption of 28.5mpg, it is not only the new performance sedan car of choice but also the perfect cross-continent express.