BMW X5 3.0sd 2008 Review

What we liked
>> Superb grunty and refined engine
>> Agile handling
>> Interior space

Not so much
>> Slightly busy ride on bigger wheels
>> Fiddly iDrive
>> Pricey options list

Overall rating: 3.5/5.0
Engine/Drivetrain/Chassis: 4.5/5.0
Price, Packaging and Practicality: 4.0/5.0
Safety: 3.5/5.0
Behind the wheel: 4.0/5.0
X-factor: 3.5/5.0

About our ratings

OVERVIEW
There is no doubt about the sales success of BMW's X5 SUV. Since its release it's been the sales powerhouse of the top-end of the SUV segment. And the arrival of the latest E70 variant has done nothing to slow the trend. Even in 2007's model changeover period the vehicle took out the top spot in the luxury SUV segment with 3399 sales -- a whopping 17 per cent of the market in which it plays.

Of the available variants by far the biggest seller has been the 3.0-litre turbodiesel. Thus with the sole turbodiesel accounting for around 70 per cent of sales, when it came to adding another engine variant to the new E70 line-up, it made sense to make it another diesel.

And that is exactly what BMW has done with the launch of the X5 3.0sd. In line with the brand's performance image, the new diesel ups the ante in power and torque via the addition of a second turbocharger to what is essentially the proven 3.0-litre straight-six diesel that graces the 3.0d.

The new 3.0sd slots into the upper reaches of the X5 range priced between the $96,300 3.0d Executive, with which it shares its spec and equipment levels, and the range-topping $118,300 4.8i petrol V8. (For a full rundown on the E70 X5, check out our launch coverage (more here).

For the 3.0sd's sticker price of $102,800 you get a full safety kit including ABS, DSC, reversing camera and six airbags, and a feature list that runs to dual-zone climate control, cruise control, leather trim, six-stack CD audio with MP3 input, satnav with television and power driver's seat, windows and mirrors.

A sport pack adds stiffer springs and dampers, sports seats, bigger 19-inch alloys (compared to the standard 18-inchers) and cosmetics at a cost of $4500. Peruse the options list further and in true Germanic style you could easily add another $20K. Try a little harder and the options bill could be double that -- just the third-row seating, glass sunroof and quad-zone air add up to $11,500!

As a performance diesel, the X5 3.0sd is pitched against the likes of Audi's new Q7 4.2-litre TDI V8, the Range Rover Sport 3.6-litre TDV8 and Volkswagen's twin-turbo V10 Touareg. Resist that $20K of extra options and the 3.0sd undercuts the above trio on price -- by a hefty $20K against the Audi and VW, and $6000 against the Rangie.

And with the lowest power and torque figures of the group (it matches the Rangie for kW), the BMW also significantly undercuts its rivals on fuel consumption -- at a combined figure of 8.8L/100km, by more than 2.0L/100km.

That doesn't mean it's the slowest, however... Only the Audi outpaces the X5sd in the 0-100kmh sprint, though the margin is considerable at 6.4sec versus 7.2.

MECHANICAL
The 3.0sd's ace in the hole is its twin-turbo direct-injected diesel engine which develops 200kW at 4400rpm and 565Nm at 2000rpm. These outputs compare to the single turbo 3.0-litre straight-six sibling which boasts 160kW at 4000rpm and 500Nm in a useful band from 1750-2750rpm.

Unlike, the twin-turbo petrol six in the 335i, the 3.0sd's engine features sequential blowers of differing size. While the petrol engine is effectively two turbocharged three-cylinder engines, the twin-blowers of the diesel operate in series. At lower revs, the smaller of the two blowers builds to maximum boost rapidly to reduce any take-off lag. As the engine speed rises the second, larger turbo comes into play, boosting the power and torque further right through the rev band.

Though there's myriad detailed changes required to make everything work, that's essentially the difference between the diesel models. Like all X5s, the sd features BMW's electronically-controlled xDrive system and a six-speed automatic transmission. Underpinnings are also unchanged -- four-wheel disc brakes, fully independent suspension with double wishbones at the front and a multi-link arrangement at the rear.

Remarkably, despite the significant increases in power and torque over the single turbo diesel, the ADR 81 combined fuel consumption for the sd is just 0.1L/100km higher than the cooking-model 3.0d. Too good to be true in the 'real world'? Perhaps...

ON THE ROAD
There's a reason why BMW's X5 3.0d has been the best-selling model in the range and it's not just down to fuel economy. Truly one of the best diesel engines around today, the question on many people's lips has been: "How are they going to top this?"

Enter the 3.0sd and the addition of the second turbocharger has made this powerplant even better. Smoother and delightfully refined, it is a match and then some for most of the petrol engines currently under the bonnets of SUVs. Indeed, we go so far as to say the blend of power, performance and fuel economy delivered by the sd makes the V8 petrol X5 obsolete.

Insert the key and press the X5's somewhat gimmicky starter button and from the driver's seat there is barely a sound. Not just an absence of a diesel tick, but almost total silence.

A decent prod of the accelerator has the big wagon moving away from standstill smartly and smoothly and again, the only indication the sd's engine is diesel rather than petrol is the tacho that's redlined at a low 4750rpm. The six-speed auto shifts with such silkiness that the progression under moderate throttle is just one creamy and strong rise in speed that reaches the limits of legality very quickly.

But to truly appreciate the benefits of the twin-turbo set-up you need to knock the transmission into manual mode and dump the right boot hard.

Off the line it is all go without a hint of lag as the engine delivers a very strong surge from just off idle. Through the grunty midrange there is no evidence -- aural or physical -- of the turbos 'passing the baton' and the engine revs continue to build power (and speed) in a superbly linear progression.

Reaching the upper limits of the rev band, the car is still pulling hard unlike many other diesels. If you fail to flick the gearshift lever in time it will shift up for you at around 4500rpm before its hits the soft limiter and the acceleration recommences.

This is an engine that delights in being driven hard and thankfully, the rest of the car is up to the task. As we have said before in reviewing the rest of the X5 range, few other SUVs have the same sort of agility and handling capabilities as the big Beemer and the sd is no different.

In standard suspension guise, it is more than composed punting along a winding stretch of blacktop with good steering feel, minimal body roll and plenty of grip from the wide 18-inch rubber. Add in the optional Adaptive Drive ($6700 plus $2000 for the required self-levelling suspension), as was fitted to one of the cars we drove on the media launch drive through central Victoria, and it takes the roadholding up a notch with the system effectively cancelling out all body roll. The flat cornering control that you have as a result belies the car's size and mass.

Ride quality in both versions is on the firm side but even pushing along at a fairly decent rate on a particularly rocky dirt section it remained comfortable with the harsh edges nicely muted. On the road, the 19-inch wheels and tyres of the sport kit-equipped X5 transfer more road surface information than some might like, but it's never uncomfortable.

What didn't match BMW's stats, however, were our fuel economy figures which finished at around 12.1L/100km. For the record, we drove hard with little consideration to economy over the 300km-odd route.

Take some consolation from the fact that with the engine ticking over at a lazy 1800rpm and a little more temperate attitude, the sd readily returned under 10L/100km during our stint of 100km/h highway cruising. It'll be interesting, nonetheless, to get feedback from owners whether BMW's claims (that the sd is as frugal as the d) hold true.

The 3.0d has been the sales powerhouse in the lineup for reasons that go well beyond its economy and the same can be said for the sd with the added appeal of even greater performance. Its driveline is definitely the pick of the range and for buyers who like their wheeltime to be more than just A-to-B transport, the sd offers all the driving pleasure of the V8 petrol X5 without the financial pain -- or environmental guilt.

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