If there’s such a thing as a sensible high-performance SUV this is about as close as it gets, but its talents don’t run deep

Rating
Pro	mpressive powertrain, torque for days, relatively efficient
Con	Ride quality on 21s isn't good

Look through the BMW X3 M40d’s numbers and it makes for some good reading if you’re in the market for a fast family hauler. Its 335bhp is nice, but the 516lb ft of torque from 1750rpm is better. Acceleration is extremely strong as a result, with 0-100Kph dealt with in 4.9sec, and it’ll top out at 250kph, which will come in handy on those autobahns en route to the Austrian Alps you’ll no doubt be visiting. Plus, the X3 is spacious and useful for just such tasks, but not so big as to become obstructive. It’ll even do over 7L/100km. But as is so common with these ‘numbers’ cars, execution trumps all, and that’s where things become a little more complicated for BMW’s midsized M Performance SUV.

First things first, the powertrain really is impressive. The 40d nomenclature signifies the use of BMW’s excellent B57 3-litre diesel engine that in this instance is tuned to its highest output this side of the quad-turbo set-up found in the X5 M50d. It’s very refined, even at start-up, and once warmed through unleashes a furious amount of performance while barely breaking a sweat. In-gear torque is pretty monstrous, and the M40d feels more well endowed than its 335bhp would suggest.

The eight-speed ZF auto transmission helps in this respect; gearing is both typically short and the shifts themselves very quick, clean and responsive. There is some turbo lag if you catch the 3-litre off guard, but when the turbo is puffing it has all the performance you could reasonably want in any gear and across most of the rev band. The transmission seems to know this fact, too, so feels superbly calibrated to the engine, holding on to higher gears and surfing the torque despite the temptation to drop a few cogs and find itself floundering at the top of the rev band.

The styling has also been cleaned right up compared to the original X3 of this generation, with slicker graphics front and rear, plus some snazzy new LED lights. Bespoke to M Performance models are a set of 21-inch wheels, some trapezoidal exhaust pipes and a questionable application of those winged M side mirrors. Inside, things have been given a bigger update alongside the wider X3 range, with a whole new dashboard integrating a larger screen and some updated BMW design motifs. Interior quality is also excellent, with a solidity to the build matching the use of materials. Most plastics are soft to the touch, and aside from some occasional faux stitching (can we try to cancel this little detail along with black wheels, please?) it’s all very slick and sophisticated inside – even considering the near-$75k base price.

But, and there was always going to be a ‘but’, while the powertrain might exude a treacly smoothness, the same can’t be said of the chassis. All the ingredients are there, but BMW seems to have rationalised that super-tight damping is more important than even a semblance of suppleness – this is a diesel SUV, remember. There is some inherent discipline in the X3’s damping as on super-smooth roads it does a good job of absorbing large undulations and suppressing them in one slick movement, but as soon as smaller, sharper intrusions come along they run out of ideas as the shock is then transmitted straight up through the wishbones. The 21-inch wheels certainly don’t help, as while there looks to be a fair amount of sidewall, it’s the excessive unsprung weight that lets the side down. The irony of all this are the spring rates, which feel oddly low – meaning that despite this brittleness actual body control isn’t great. There’s also the small issue of mass, as despite some relatively sensible exterior dimensions, the X3 still weighs over two tons.

Drive through the battering ride quality and things don’t really get much better, as the steering is typically numb and despite initially feeling like it has a nice rear-drive balance, try to exploit all that torque at low revs and things are much more nose-led than is ideal. Push beyond the grip threshold, even with some real provocation, and it’ll be the front end that pushes.

So while this might be passed off as to say about a diesel SUV, this inherent balance is what should separate X3s from their rivals. An Audi SQ5 is a little more leaden to drive at this same pace, but its far more sophisticated ride quality actually makes it a nicer car to punt along at lower speeds. Even keeping things sensible, the indecent ride quality makes the X3 M40d a bit of a pain in everyday driving and remains a big old fly in this car’s otherwise well-formed ointment.

Prices and rivals

While it feels like anything BMW does, Audi will follow, in this case the fast, midsize premium SUV was an Audi thing first, hence why the SQ5 has garnered such an intense following over the years. The same copycat approach applies now, as its latest form has seen the reinstatement of a twin-turbo diesel V6, this time with mild-hybridisation. Performance and price are also pretty much bang on between the two, with the SQ5 yours from $73,470 on the road.

The Porsche Macan isn’t available in diesel form, the Macan S and GTS instead straddling the BMW with their 2.9-litre V6 petrol units. They might use more fuel, but in both cases represent a much more dynamically sorted (and desirable, let’s be frank) package. Merc’s GLC43 is another petrol option, but it’s less of a rival and more a badge engineering exercise, even if its twin-turbo V6 is actually the most charismatic engine in the class.

Unfortunately, the reality with all of these midsized performance SUVs is that the standard estates they’re based on are just so much better to drive, cheaper to buy and no less practical given off-roading capability is about as relevant as lock-stop oversteer. You want a do-all daily driver with a big boot? Go for a BMW M340d – it’s just better.

This article originally appeared at evo.co.uk

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