Demand reduces local supply

The world's first common-rail, horizontally opposed turbodiesel has just arrived in Europe in the Liberty and Outback. In Europe diesel is cheaper and demand for diesel-powered cars is high. In the UK, diesel Libertys and Outbacks are likely to account for about 80 per cent of sales.

The new Forester received the engine in September and Impreza three months later. Subaru Australia had initially hoped to get the diesel into the Forester when it's launched in March. Now, because of the European demand, this is unlikely, spokesman David Rowley says.

However, the redesigned Outback and Liberty due next year are tipped to have the engine. The 2.0-litre TD Subbie engine develops 110kW at 3600 revs and 350Nm at 1800 revs.

Subaru set out to make the common-rail engine exceptionally smooth, quiet and refined.

It is similar in size to the 2.0-litre petrol engine and, like its petrol cousins, the turbo-diesel sits low in the engine bay, giving a low centre of gravity. Subaru says the Liberty

TD can hit 100km/h in 8.5 seconds and has a top speed of 202km/h.

The Outback takes 8.8 seconds to reach 100km/h and has a fractionally slower top of 199km/h. The engine is the first diesel developed in-house by Subaru after more than 40-years expertise in boxer engine technology.

There are some differences compared with Subaru's 2.0-litre petrol engine.

The 2.0-litre diesel has an 11mm longer stroke and 6mm smaller bore for a capacity of 1998cc v 1994cc. Bore pitch has been shortened from 113mm to 98.4mm.

Overall engine block length is only 353.5mm, compared with 414.8mm in the petrol engine.

The block is made of an extremely rigid design.

All five main bearings in the alloy cylinder block also use metal composite supports for strength and durability. The diesel has liquid engine mounts, with the body benefiting from extra soundproofing. The five-speed manual gearbox has higher ratios to suit the diesel's stronger torque and lower engine speed.

The variable-vane turbocharger is mounted under the engine for low centre of gravity.

A fast-warm catalytic converter is also mounted under the engine. The power-steering is electric, to improve fuel economy, yet is tuned for strong feel and response. The front spring rates and front brakes have been beefed up.

This enables them to cope with extra weight.

Even the airconditioning unit has been modified to provide hot air earlier in the engine's warm-up cycle. The diesels also share the same bonnet scoop as the turbocharged petrol models.