Land Rover Discovery SD4 review: four-cylinder SUV driven

Another Land Rover Discovery review. What's this one?

This is a Discovery powered by the bottom-of-the-range engine, a 2.0-litre four-cylinder diesel. It has 240bhp, a claimed 43.5mpg, and starts below £44,000.

It’s a rival for some other four-cylinder diesels such as the BMW X5 25d, Mercedes GLE 250d and Volvo XC90 D5. But it will also tackle some V6s, including the Audi Q7, Jeep Grand Cherokee and VW Touareg.

But that list is pretty diverse because there's not much like a Discovery. So if you want a Discovery, you'll probably accept no rival substitute. But you do now get an engine choice.

As well as a supercharged petrol engine for those who buy their loved ones petrol station carnations every day, there are two diesels. Is this SD4 the right one, or should you still opt for the V6? Well this, says Land Rover, manages better performance than the V6 did in the old Discovery.

How come?

This hulking seven-seater SUV has lost 400kg on its predecessor. Which means the new engines don't have to work so hard, so it can get away with a smaller one, the new four-cylinder.

And in a wonderful example of the downward weight spiral, the engine weight of the four-cylinder is 100kg or so less than the V6, so in total you've lost 500kg. Half a tonne. A Caterham, almost.

That's the theory. What did you actually, er, Discover?

I hesitate to confess, but I didn't realise at first that two cylinders were absent. I was being driven by a friend in the SD4. We were making good and peaceful progress. Then I looked at the spec sheet, realised what was under the bonnet and had a drive myself.

I deliberately held it in low gears and used big revs, because they are good ways to expose any ill-manners of a four. But still I was impressed.

What engine is it?

A more powerful version of JLR's diesel Ingenium family. Something we’ve not always been kind about in the past.

This 240bhp twin-turbo version is by far the best example yet, though. The older Discovery Sport has one turbo and is mounted transversely. This, in contrast, is a twin-turbo longitudinal installation. It's smooth and quiet.

But you'd still want the V6?

Of course, but the numbers make it hard to justify. The SD4 has 93 per cent of the TD6's power and 83 per cent of its torque. Because it's lighter, the 0-62mph figure trails by just 0.2sec, at 8.3secs. The TD6 costs £1,500 more on like-for-like cars.

Neither engine can really overcome the Discovery's farm-shed air resistance, so A-road overtaking needs lots of space. But the V6 feels a bit more effortless.

And what about the rest of the road behaviour?

The new Discovery's on-road manners are imperious, thanks to a nice soft ride and surprisingly precise steering. It's never car-like, though, and doesn't want you to go berserk through a series of bends.

The technique with the old one was as follows: brake smoothly, count to three, then turn into a bend. In the new one you can just count to one. Which isn't counting really is it? You just drive the thing, without having to make particular allowances.

Just as we ask about the track performance of sports cars, how's this for off-roading?

Astounding, even on standard tyres. All versions get a low-range gearbox, air suspension you can hike up and second-generation Terrain Response.

It'll wade to the tops of its tyres, with a pair of ultrasound sensors telling you how close to the depth limit you are. In a deluge, even on the road, that could save your bacon. It eases through foot-deep muddy ruts, goes across and down precipitate slopes and for all I know it will ascend the Pyramid of Giza.

And all in carpeted luxury. Top-end Land Rovers manage a spellbinding contrast between the hostile environment outside the windows and the warm luxury within. The Discovery's cabin is a gorgeous mix of clean design with plush materials.

What about practicality?

For absolute maximum luxury, you will of course require a Range Rover. But keen Discoverists will be coming back for more because of the cabin practicalities. The interior is versatile and magnificently thought-out for any combination of seats, from two to seven.

All the chairs hold grown-ups and provide storage and charging for the provisions and devices mandatory to long-distance travel. For the driver, long journeys are eased, at last, by the assistance and connected navigation that its rivals have done so well for so much longer.

Still a favourite then?

We're slightly unconvinced by the looks. The old one was just so clear in purpose, while the new has a slightly slippery ambiguity. But under the metal the Discovery is an unmatched combo of limousine, minibus and quad-bike. Even if you’ve downgraded from six to four cylinders.