07/05/2008 13:35
Model/Engine size:2.0 TD R
Fuel: Diesel
Fuel economy combined: 48.7 mpg
Want to know a secret? A secret that very, very few people, motoring journalists included, have realised? It’s this: a certain new car has just appeared on the scene, and it’s not only the most economical 4x4, it’s the most economical 4x4 by a huge margin.
The best economy figure from a 4x4 is currently 43.5mpg from the BMW X3 2.0d. The Honda CR-V and the Jeep Compass also achieve 43.5mpg, then there is a range of 4x4s that manage somewhere around 42 and 43mpg. So it seems that manufacturers of 4x4s have hit a limit of 43.5mpg – that’s as good as they can get.
Except that Subaru has suddenly, from nowhere, produced its first ever boxer diesel engine, put it in the Legacy Outback, and it returns an average of 48.7mpg. This is not just slightly better than the nearest competitor – this is a huge quantum leap of more than 5mpg. It’s more than 10mpg better than the Land Rover Freelander, which can only manage 37.7mpg. And unlike many other cars, our road test proves that we can vouch for the fact that 48.7mpg is very achievable in real life.
But not only does the 150 PS boxer diesel Outback (and Legacy Sports Tourer) have the best fuel efficiency in the 4WD class, it also beats all main 2.0 litre two-wheel drive rivals including the new Ford Mondeo TD and VW Passat – both in lower-powered 140 PS formats. The 2WD Ford Mondeo estate equivalent returns 47.9mpg with 156g/km, while the VW Passat 2.0 TDI estate can only manage 47.1mpg and 158g/km.
So exactly what is a Subaru Legacy Outback? Most people will associate Subaru with Colin McRae and the winning of World Rally Championships. The Subaru Impreza has the Subaru ‘trademark’ layout: a boxer engine with symmetrical permanent all-wheel drive. This means that the transmission, transfer to propeller shaft and rear differential sit in a straight line behind the boxer engine. This is the configuration that has proven itself to be so effective in high speed rallying on slippery surfaces around the world.
The Subaru Forester is based on the Impreza, but it has higher ground clearance and comes just in an estate body style. The Legacy is the bigger brother of these two models – and comes as a saloon or estate road car, or as an estate with 200mm of ground clearance: this is the Outback.
To date, all Subaru road cars in the UK have only been available with a petrol engine, which severely limits their sales in this sector. So now Subaru has developed its own diesel engine, from scratch, and based it on the petrol boxer engine.
Why does Subaru stick to the format of a boxer engine? In most car engines, the cylinders are upright, resulting in the engine being relatively tall. In a boxer engine, the cylinders are horizontally opposed, which means that the centre of gravity is lower than other engines.
Subaru Legacy Outback Diesel
This is a key contributor to Subaru’s consistently critically-acclaimed handling. . It also means that this new boxer diesel engine has excellent balance and low vibration, and it is compact and lightweight. It meets Euro4 emission standards thanks to oxidation catalytic converters, a particulate filter and exhaust gas recirculation.
Not only is this turbo-diesel engine incredibly economical, with correspondingly low emissions, it’s also amazingly smooth and quiet. And it’s responsive, fast, powerful and has excellent torque. Surely there can’t be any more plus points about this car? Well, read on...
Just in case you think that the Outback is not really in the same class as other 4x4s in terms of off-road ability, you’d be wrong. Yes, we all know that Subaru’s all-wheel-drive system wins rallies, but it also means that it is more capable than you might imagine off-road. OK, the Outback is a long car so it’s never going to be able to negotiate a true off-road course that a Land Rover Defender could crawl around, but how many people buy a 4x4 in this sector to do that? The Outback provides well-engineered family estate transport that is also highly secure in conditions of low grip such as snow and muddy country lanes – as well as wet roundabouts. The AWD, rather than a four-wheel-drive, system means that it is permanent, and if a wheel slips the torque distribution between front and rear is controlled automatically.
Remember also that Subaru consistently comes near the top of reliability surveys around the world, and there are many ageing Subarus that can still be found tucked away providing durable and dependable transport on farms throughout the UK – as well as in mountainous and inhospitable terrain around the world.
So what’s the Outback diesel like to drive on normal roads? It’s incredibly quiet, smooth and vibration-free. Only at start-up and at low speeds are you aware that you’re driving a diesel. On motorways and A-roads this car represents a revolution in diesel power. It has a smooth torque curve rather than an explosive one that you would find in fire-spitting Impreza rally cars. As with all other Subarus, compared to most 4x4s, the driving experience is one of a responsive car, not a diesel utility vehicle.
What about Subaru’s other engineering features? The Outback’s power-steering is now electric to improve fuel economy, and the front brakes have been uprated. Suspension is conventional struts at the front and multilink at the rear. It has self-levelling as standard and a centre differential with viscous rear LSD (limited slip differential).
The Outback is also very spacious. However if you think you want a tall and boxy 4x4, you may need to approach the Outback with a different mindset. Tall and boxy 4x4s mean a high centre of gravity, wallowing cornering manners, awful aerodynamics and terrible fuel consumption. The Outback is a long 4x4, not a tall one.
If you are in the habit of wearing tall hats while you drive, maybe this is not the car for you; if you want a normal estate car with a raised ride height that cuts through the air smoothly (it has a Cd figure of 0.34, helped by aerodynamic detailing such as special engine undercovers, spoilers and wheel flaps), then you should consider the Legacy.
So surely there must be downsides to the Outback? Well, although the diesel engine is brand new, it’s packaged in a car that has been around for a while. . The only visual clues to the identity of the diesel are the new bonnet air intake scoop and the badge on the tailgate.
Compared to some models, people may find that the Outback’s interior is not particularly modern, stylish, high quality or ‘posh’. However Subarus are generally bought for fitness for purpose and their substance rather than their latest fashionable style. A limited choice of colours may be a valid concern; the Outback is available in just six options: black, white, silver, gold, blue or grey.
The Outback is great to drive, but it is a large, long, and, despite weight saving feature such as the compact engine and aluminium bonnet and tailgate, it is still a relatively heavy diesel car. Therefore if you are expecting the handling fluidity of an Impreza you’re likely to be disappointed. And the diesel Outback only has a five speed gearbox – a six speed box would be better, although the car still cruises very effortlessly and quietly at motorway speeds with the current set-up.
Probably the biggest barrier to ownership of this car is the fact that it isn’t a Ford, BMW or any other of the more familiar brands. People will simply just not have the Outback on their radar. If they see a diesel Outback, they probably won’t be aware that it’s a diesel, and will dismiss it as a petrol-munching niche product. However in practical terms a real problem will be the availability; only a handful of press cars and dealer demonstrators are in the UK at the moment; the next batch of diesel Legacies and Outbacks won’t be available until July, when dealer allocations are already being spoken for.
So in summary the Subaru Legacy Outback diesel is the most economical – and lowest emission – 4x4 that you can buy – by far. It is also extremely smooth, quiet and refined. It drives like a car, and has the capacity of a large estate. It will last forever, and although it’s not a brand new ground-breaking exterior design, it still looks classy in an understated way. It has the genes of the World Rally Championship winning Impreza, and it will surprise many Land Rover owners off-road. 
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