What is it?
BMW was initially quite reticent to apply its revered M badge to any of its dedicated four-wheel drive models over concerns that such a move may harm the blue chip image enjoyed by its performance models.
But after witnessing a huge increase in demand for performance based four-wheel drives, it launched the rapid X5 M50i and X6 M50i in 2009 prior to launching even more powerful successor models in 2014.
Now, some six years after its first performance SUVs first hit showrooms, BMW has introduced a smaller and more affordable alternative in the form of the X4 M40i; a car clearly aimed at challenging the likes of the recently introduced Porsche Macan GTS.
The X4 M40i takes the turbocharged 3.0-litre in-line six-cylinder engine of the X4 xdrive35i and combines it with various performance enhancing components already used in the M3 saloon and M4 coupe and cabriolet.
Included in the M division makeover of BMW’s latest straight six are new pistons featuring a new top ring design, additional boost pressure for the twin-scroll turbocharger, revised crankshaft bearings, a modified inlet manifold for improved breathing potential and a separate oil cooler. They’re similar changes to those brought to the engine used by the new M2, no less.
As a result, power has risen by 54bhp over the existing top-of-the-line X4, taking it up a Porsche Macan GTS equalling 355bhp.
It is a sufficient lift to provide the 1840kg X4 M40i with a power-to-weight ratio of 193bhp per tonne - some 27bhp per tonne better than that of the 1815kg X4 xDrive35i and a 6bhp per tonne increase on the Macan GTS.
There’s greater torque, too. Some 48lb ft of it to be precise, endowing the latest high-riding M model with 343lb ft of twist on an impressively wide band of revs between 1350 and 5250rpm.
In combination with a standard eight-speed M-Steptronic automatic gearbox with a unique M division software map and a four-wheel drive system that runs a more rearward bias than that seen in standard X4 models, the powered-up engine provides the X4 M40i with a claimed 0-62mph time of just 4.9sec along with a limited 155mph top speed.
By comparison, the X4 xDrive35i receives respective figures of 5.5sec and 154mph, while the Macan GTS boasts an official 5.2sec and 159mph. Fast by class standards, then.
Accompanying the wholesale lift in reserves is reworked suspension featuring increased camber and strengthened wishbones up front, as well as stiffer springs, altered electronic mapping for the adaptive dampers and larger diameter anti-roll bars at each end. The variable ratio electro-mechanical steering system also receives specific tuning for what the BMW M division describes as “heightened steering precision”.
The standard wheel and tyre package mates 245/45 R19 front and 275/40 R19 rear Michelin Primacy run flats with 8.5J x 19-inch and 9.5J x 19-inch rims. Those seeking ultimate grip should go for the optional package, which uses 245/40 R20 front and 275/35 R20 Michelin Pilot Super Sports with 8.5J x 20-inch and 9.5J x 20-inch double spoke alloys.
As well as engineering its four-wheel drive system to provide a greater percentage of drive to the rear wheels, BMW’s M division has also tweaked the electronic torque vectoring system, which goes under the name Performance Contro, to alter the apportioning of drive that goes to each of the individual rear wheels in a move aimed at improving overall agility.
Rounding out the long list of changes over the X4 xDrive35i are larger brakes, a more free-flowing twin-pipe exhaust and BMW M styling embellishments inside and out.
What's it like?
The X4 M40i lives up its billing as a car for every occasion, providing relaxed part-throttle properties around town, sharp acceleration off the line, potent in-gear qualities and formidable cruising attributes at motorway speeds.
Indeed, its breath of ability really is quite impressive and marks it out as a logical choice for those seeking the ease of operation that comes with its raised seating position but unwilling to compromise of performance.
The heavily reworked BMW M division engine sitting up front is perfectly suited to the task, feeling quite a bit more muscular and yet more refined across its entire rev range than the standard unit.
It’s more vocal, too. In anything but Comfort mode, the smooth-revving unit provides an alluring soundtrack that is regularly interspersed with the odd crackle of exhaust on the overrun when you are really hauling along, all of which endows the new range-topping X4 with a distinctly sporting air.
While the engine impresses, it is the gearbox that really steals the show. The M-Steptronic unit delivers rapid and precise shifts in automatic mode, whether tooling around town at part throttle or blasting along country roads at full throttle.
Flick the paddle shifters behind the wheel to engage manual mode and its performance steps up a notch, delivering even faster changes under load and holding individual gears all the way to the 7000rpm ignition cut out.
Around town, the X4 M40i is smooth and, provided you’ve dialled up Comfort mode, fairly compliant. There is some underlying firmness to its progress over manhole covers and high-frequency bumps, but deft tuning of the adaptive dampers and a good deal of wheel travel help to mask any shortcomings in the ride department.
Find a suitable road and it doesn’t take long to discover the X4 M40i is much more than just a warmed over version of the X4 xDrive35i. The various changes brought to its underpinnings elevate its dynamic properties to an altogether higher level, making it a very enjoyable car to thread down challenging sections of blacktop.
The added camber up front provides more eager turn-in characteristics than you’ll find in any standard X4, and just about any rival SUV, for that matter. This endows BMW M division’s latest member with a terrifically agile feel.
Exemplary body control combines with outstanding grip to endow the new BMW with a wonderful progressive yet secure nature when you are really pushing on in Sport mode. To unlock its full potential, though, you really need to be running in Sport Plus mode, which prompts the four-wheel drive and torque vectoring systems to dole out a distinctly rearward bias of drive.
The retuned steering is precise but lacks for any meaningful feedback. It’s also good to note that BMW’s M division has adopted a new steering wheel with a thinner rim.
The rest of the package is pretty much the same as you’ll find in other X4 models; that means reasonable accommodation, a commanding driving position, logical controls and 500 litres of luggage capacity.
Should I buy one?
Short answer, you can’t. Not in the UK, at any rate.
With limited sales of petrol powered SUVs in this country, BMW has decided not to bother with the petrol-powered X4 M40i at all. Instead, it prefers to offer the 307bhp turbocharged 3.0-litre in-line six-cylinder diesel powered X4 xDrive35d, which it says is better suited to the preferences of UK buyers.
It’s a pity because this is one of the most engaging SUVs you’re likely to encounter at any price. It’s certainly right up there with the Macan GTS for outright dynamic prowess, delivering a combination of performance and agility that would make even the most ardent enthusiast stand up and take notice.
BMW X4 M40i
Price N/A; 0-62mph 4.9sec; Top Speed 155mph; Engine 6-cyl, in-line, 2979cc, turbocharged, petrol; Power 355bhp at 5800rpm; Torque 343lb ft at 1350-5250rpm; Kerb weight 1840kg; Gearbox 8-spd automatic; Economy 32.8mpg (combined); CO2 199g/km