IT IS a TDI hat-trick for the Audi A6 saloon range.

A new 2.7-litre turbo diesel injected engine promising 41mpg economy at the combined cycle, coupled with class leading tax efficiency, running costs and predicted residual values joins the saloon range this month.

It costs from £26,330 on the road, depending on the specification level, and features the most advanced diesel engine technology available, including a unique injection system.

Also, coming soon, will be the option of adaptive four-wheel air suspension for the first time in the segment.

The new six-cylinder clean and economical common rail engine developing 180PS is essentially a downsized version of the all-new 3.0 TDI, regarded as one of the most refined units ever built and used to power the A6 and A8 saloons.

Its close relative delivers its maximum 180PS output between 3,300 and 4,250rpm and 380Nm between 1,400 and 3,300rpm, giving the A6 2.7-litre TDI SE with six-speed manual gearbox the potential to accelerate from rest to 62mph in 8.1 seconds. Predictably for a TDI, this strong performance is delivered with up to 41.5mpg possible on the combined cycle, and with an impressively low CO2 output of 181g/km, depending on specification. The highly sophisticated common rail fuel injection system features what is known as piezo injectors.

For the technically minded, these feature a separate high-pressure pump and rail for each row of cylinders, and the system allows up to five separate amounts of fuel to be injected on each working stroke, at an injection pressure of 1600 bar, 250 bar more than with previous common rail systems.

This helps to achieve the best possible fuel/air mixture and an even more efficient combustion process.

The result is full compliance with EU4 emissions regulations without the use of a particulate filter, and also helps the car to benefit from a lower tax liability than any other prestige six-cylinder TDI executive saloon.

According to the latest information from a company specialising in working out car running costs, this new version also offers the lowest running costs in its specific sector, and will also achieve the best value retention over three years or 60,000 miles.

In common with all A6 saloons, the 2.7-litre TDI will from next month offer the extra cost option of adaptive air suspension. Based on the system fitted to the A8 saloon, the air suspension set-up features continuously variable damping to suit the road conditions, and also offers the option of four pre-determined suspension settings which can be selected by the driver via a special dashboard system.

The new model will be available in both SE and S line trim: the SE includes 16-inch alloy wheels, remote control central locking, electronic climate control, electric front and rear windows and mirrors, cruise control, a 160-watt sound system with glove box-mounted CD player and a multi-media information control system with 6.5-inch screen.

The S line models add 18-inch alloy wheels, unique S line sports suspension, sports seats with black leather/speed cloth combination upholstery, a sports steering wheel and special S line grille and interior badging.

An additional styling package is also available for S line models only at an extra cost of £1,100 (£875 for 4.2 quattro versions), providing an exclusive front bumper and grille design, headlamp washers and a unique rear bumper treatment with painted diffuser.

Updated: 09:13 Friday, November 26, 2004