Volkswagen's Golf line-up has been joined by a new 2.0-litre TDI engine producing 170 horsepower the most potent diesel-powered unit ever produced for a Golf.

A development of the popular 2.0-litre 140 horsepower TDI engine, this new powerplant uses Piezo electric elements to control precisely the fuel injection, maximising power output, but minimising consumption and emissions. Emissions are further reduced by a maintenance-free particulate filter. Following the success of its TDI and FSI engines, Volkswagen is also launching TSI petrol technology. TSI uses an FSI engine which is then dual-charged through a combination of an engine-driven supercharger and an exhaust gas turbocharger arranged in series.

Volkswagen says the driving characteristics of the new TSI engine are improved over those of the current FSI unit. The belt-driven supercharger operates at lower engine speeds, with the turbocharger coming in as the engine speed increases. The result of this is excellent driveability and performance throughout the range with no turbo lag and high maximum torque. The new TSI engine has a capacity of 1.4-litres and produces either 140 or 170 horsepower. The 170 horsepower version has the same peak power as a conventional 2.3-litre petrol unit, but with 20 per cent lower fuel consumption, returning 38.2 mpg on the combined cycle. These new petrol and diesel engines have prompted a revision in the Golf line-up. The existing GT trim will be altered to look more like the GTI, gaining a new front grille, GT badges, 17-inch ClassiX' alloy wheels, lowered suspension and twin exhaust pipes.

Both the 2.0-litre 140 and 170 horsepower TDI engines as well as the 1.4-litre 170 horsepower TSI petrol will be offered in GT trim. Prices will start at £17,995 for the 140 horsepower TDI; £19,095 for the 170 horsepower TDI; and £18,095 for the 170 horsepower TSI.