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From nowhere, Subaru shoots straight to class-leading economy

New diesel engine in 4x4 Subaru Legacy gives almost 50mpg

Who would have thought it? Subaru has just gone straight to the top of the class with some amazing economy figures of almost 50mpg combined from its brand new diesel engine in the Legacy.

The best economy figure from a diesel 4×4 is currently 43.5mpg from the BMW X3 2.0d. The new Legacy Outback crossover blows this out of the water with an incredible 48.7mpg – and the Legacy Sports Tourer manages an even better 49.6mpg.

Those mpg figures in more detail

The Legacy Sports Tourer 2.0TD R manages 49.6mpg combined, 56.5mpg extra-urban, 39.8mpg urban, and CO2 emissions of 151g/km. At the same time it manages 0-60mph in 8.5 seconds and a top speed of 126mph.

The Outback 2.0TD R – a crossover with increased ride height – manages 48.7mpg combined, 55.4mpg extra-urban, 39.8mpg urban, and CO2 emissions of 153g/km. At the same time it manages 0-60mph in 8.8 seconds and a top speed of 124mph.

This is Subaru’s, and the world’s, first boxer diesel engined-passenger car. And of course both Legacies also come with Subaru’s legendary and rally-proven symmetrical all-wheel drive system and low centre-of-gravity.

On sale from February 2008, the Legacy Sports Tourer and Outback crossover mid-sized estates are priced from just £19,995 for the Legacy 2.0TD R model. Subaru says that saloon versions may follow once supplies become more plentiful.

The yet-to-be introduced new Forester will get the new engine in September and new Impreza three months later.

Subaru is keen to point out that the 150 PS Boxer Diesel Legacy and Outback not only have the best fuel efficiency in the 4WD passenger car class but beat 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 gives 47.1mpg and 158g/km.

Comparing the new Legacy Sports Tourer with the 4WD version of the Passat – called the 2.0 TDI 4Motion – shows the Subaru to be 8.7mpg better on the combined cycle with emissions improved by 31g/km compared to the VW.

Subaru also claims that refinement is also a Boxer Diesel strongpoint, with official moving sound levels of 70.5 dB (A) compared to the Mondeo’s 71.0 and Passat’s 73 dB (A), and even a Rolls-Royce Phantom is higher at 72.0 dB (A).

Subaru’s special Boxer Diesel features

The company has developed certain special features for the diesel, such as liquid mounts for the engine, with the body benefiting from extra sound-proofing to enhance refinement, while the five-speed manual gearbox has higher ratios to suit the diesel’s stronger torque and lower engine speed.

The power-steering is now electric to improve fuel economy and is tuned for a better feel and response. Front spring rates have also been tuned to suit both the diesel engine and new steering system.

The Boxer Diesel’s front brakes have also been uprated and the gear-lever length reduced slightly for a sportier, shorter throw.

Even the air-conditioning unit has been modified to provide hot air earlier in the engine’s warm-up cycle, as diesel engines have different characteristics to petrol powerplants.

Visual changes include new cloth seat trim for Legacy and Outback R models and a discreet bonnet air intake scoop.

Dedicated to the horizontally-opposed ‘boxer’ engine layout for over 40 years, Subaru engineers were determined to use the same format for their first diesel engine. This was to create a light, compact, strong unit with reduced vibration, noise and internal friction compared to an in-line engine, and for an ultra-low centre-of gravity. This enhances handling agility and roadholding – especially when combined with Subaru’s renowned symmetrical all-wheel drive system.

In addition to the entire engine and transmission being mounted very low down, it’s also within the wheelbase to further boost chassis dynamics.

The Boxer Diesel meets Euro4 emission standards thanks to oxidation catalytic converters, a particulate filter and exhaust gas recirculation.

The new Boxer Diesel produces 150 PS at 3,600 rpm and 258 lb ft torque at 1,800 rpm.

Even the aerodynamics are good, with Cd figures of 0.30 for the Sports Tourer and 0.34 for the Outback (helped by aerodynamic detailing such as special engine undercovers, spoilers and wheel flaps).

’08 Boxer Diesel Legacy Sports Tourer Line-Up And Prices:

2.0TD R manual – £19,995

2.0TD RE manual – £21,995

2.0TD REn (navigation) manual – £23,395

’08 Boxer Diesel Outback Line-Up And Prices:

2.0TD R manual – £21,495

2.0TD RE manual – £23,495

2.0TD REn (navigation) manual – £24,895