Subaru Outback 2.0D 2010 Review

RRP: $40,490 (manufacturer's list price, excluding on-road costs and dealer delivery)
Options fitted to test car (not included in above price): nil
Crash rating: five-star (ANCAP)
Fuel: Diesel
Claimed fuel economy (L/100km): 6.4
CO2 emissions (g/km): 168
Also consider: Skoda Scout; Volkswagen Tiguan diesel, Nissan X-Trail diesel, Hyundai ix35 diesel

Overall rating: 3.0/5.0
Engine/Drivetrain/Chassis: 3.0/5.0
Price, Packaging and Practicality: 3.0/5.0
Safety: 4.0/5.0
Behind the wheel: 2.5/5.0
X-factor: 2.5/5.0

About our ratings

Subaru attracted above-average interest when it became known the company was developing a turbodiesel version of its horizontally opposed four-cylinder 'boxer' engine.

Boxer engines are hardly rare -- the concept was patented by Karl Benz in 1896 and is used today in both the motorcycle and car industries -- but diesel boxers are. A bit of research shows only one boxer diesel of significance, and that was a 12-cylinder monster that powered Hino trucks for a few years at the end of the 1960s.

So Subaru more or less went it alone when developing the turbodiesel now available in its Outback and Forester SUVs.

The company's need for a diesel had been evident for some time. Diesel-dominated Europe's growth as a market of interest for Subaru paralleled the trend to diesel in SUVs both home and abroad. Indeed, by the time Subaru joined the throng, only a handful of SUV-makers were persisting with an all-petrol engine lineup.

Subaru could undoubtedly have grabbed a conventional inline four-cylinder diesel from somewhere else for adaptation to its two SUVs, but the defining role of the company's boxer engine was too significant for that.

Although the new engine appears in many ways similar to the petrol versions, there are myriad changes that make it high-compression diesel-ready. And the diesel adopts a perfectly square bore/stroke ratio that contrasts with the significantly short-stroke configuration of the 2.5-litre petrol Outback. This helps with the low-speed torque characteristics that have not always been a strongpoint in petrol Subarus -- but more of that later.

In the Subaru Outback, the 2.0-litre turbodiesel produces 110kW and 350Nm which, on the face of it, is perfectly reasonable. The diesel Outback has more power and torque than the slightly smaller yet heavier Skoda Scout (its closest competitor), Volkswagen's Tiguan 2.0-litre turbodiesel but doesn't match the strong performance of Nissan's X-Trail turbodiesel. The Subaru, however, is ahead of all in fuel economy. The only real deficit that shows up on paper is that, so far, the Subaru is only offered with a (six-speed) manual transmission. It shares this shortfall with the Skoda Scout.

For Subaru, the important thing is that the turbodiesel Outback is more economical, and cleaner, than the 2.5-litre petrol version. The official figures are 6.4L/100km and 168g/km, which measures up well against the manual-transmission petrol engine's 8.9L/100km and 209g/km (the CVT petrol is slightly better with 8.4L/100km and 198g/km).

Quoted acceleration figures show the turbodiesel Outback is virtually lineball with the petrol versions, quoting a claimed zero to 100km/h figure of 9.7 seconds -- only 0.1 of a second slower than the manual petrol. Even though the kilowatts are down on the petrol 2.5-litre engine's 123kW, the turbodiesel's 350Nm of torque (the petrol engine produces 229Nm) helps here -- and even more when it comes to overtaking on the open road.

The bottom line: similar performance but with more mid-range grunt, lower emissions and better fuel economy.

In terms of standard kit, the turbodiesel Outback sticks to pretty much the same formula as the petrol versions. Base models in either case feature stability control, anti-lock brakes with electronic brakeforce distribution and brake assist, hill-start assist and a full complement of airbags including dual front, front side, full-length curtain and a driver's kneebag.

Standard gear in base versions as tested here includes dual-zone climate control, electric park brake, trip computer, cruise control, manual front seats, cloth trim and a six-stack in-dash CD player with six-speaker audio.

More crossover than SUV, the Outback diesel is nevertheless more capable on a rough track than the Liberty wagon on which it is based. Better ground clearance (213mm) and a self-levelling rear suspension help keep the undercarriage out of harm's way and extend the capabilities of Subaru's symmetrical all-wheel-drive system.

So how does Subaru's first diesel function as an alternative to the normal petrol boxer engine? And how does it compare with conventional inline four-cylinder diesels?

In terms of smoothness and operational noise levels, it undoubtedly benefits from the inherent balance of the horizontally opposed layout. It is an unobtrusive diesel, and the low-slung, forward location helps remove sound sources further away from the cabin. The normal clatter -- with a touch of boxer beat -- is there of course, but it sounds rather distant at idle and disappears altogether once the Outback is up to speed.

The figures also indicate very good torque characteristics, with the 350Nm max coming in from 1800rpm and holding steady until 2400rpm. This is entirely acceptable and competitive with other 2.0-litre turbodiesels.

In practice, the Subaru still suffers a certain tardiness in off-the-mark torque delivery. It feels relatively high-geared and, compared with the manual petrol version in the intermediate ratios, it is. First and sixth are the same, but from second to fifth gears the box tends towards taller ratios undoubtedly calculated to capitalise on the higher torque.

The end result is that the diesel feels less perky than you might expect. The relatively narrow rpm band at maximum torque means upshifts should be made early rather than late, and here the wider gaps between gear ratios come into play. Then there's the dead-square bore-stroke ratio that contrasts markedly with the long-stroke configuration normally used in other similar-size turbodiesels to extract the best possible torque.

That said, the Outback pulls with turbodiesel verve once on song. It just needs a bit more attention to being in the correct gear than some of its competitors. An auto transmission would be nice.

As far as economy is concerned, the Subaru does well. It is better for example than the Skoda Scout and VW's manual Tiguan diesel, both of which average 6.6L/100km, and it is better than the manual Nissan X-Trail's 7.5L/100km.

In all, the Outback diesel does pretty much what you'd expect it to do. If the mid-range response is a bit less than some of its competition (Hyundai's new ix35 turbodiesel with 135kW and 392Nm -- but thirstier and less clean -- comes to mind), then there's good economy, low CO2 emissions and the quiet and smooth operation to compensate. The experience is otherwise the same as in a petrol Outback.

There are the unquestioned benefits of the Outback/Liberty's growth in size, with much more accommodating front and rear seats, and the seven-airbag system that plays a big part in the five-star ANCAP rating. Visually, about the only difference is the bonnet scoop otherwise seen in the Liberty Turbo.

The bigger, longer-wheelbase body means the cargo area is better than previously, and nobody is going to complain about a cargo volume that stretches from a decent 490 litres with all seats in place to 1690 litres with the split-fold rear seat laid flat. And the self-leveling rear suspension ensures its generous ground clearance is maintained even when the Outback is loaded.

Because of its higher-set suspension, the Outback feels a little more body roll than regular Liberty wagons, but the driver soon attunes to this, while the ride quality seems to benefit from the extra suspension travel available. It's better in this regard than the more upright, purpose-built SUVs.

Compared to much of its opposition, the Outback also benefits from full-time, three-differential all-wheel drive, which aids stability on the road while offering a degree of off-road work where its capabilities are equivalent to most compact SUVs -- with some exceptions, including the likes of Nissan's X-Trail. If you want a little more ability in the bush, the just-launched Subaru Forester diesel might do the trick.

With a $2500 premium over equivalent petrol Outback models, the diesel is an option that should be carefully considered. Subaru reckons on average it would take about 20 months to cover the extra purchase price in fuel saved.

Any car that runs cleaner and more economically, yet has equal on-road punch to an otherwise-equivalent model just has to make sense.

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