PSA Peugeot-Citroen is widening its use of petrol engines developed jointly with BMW, replacing two older units in its updated D-segment C4 line.

The 1.6-litre petrol engines are the 120hp VTi (Variable valve lift and Timing Injection) and 150hp THP (Turbo High Pressure)units replacing the older 1.6i 16V and 2.0i 16V motors respectively. Citroen said they deliver improved fuel economy and lower emissions while new low-rolling-resistance Michelin Energy Saver tyres also improve efficiency.

After almost 900,000 sales world-wide, the C4 will appear at October's Paris motor show with a restyled nose, similar to the C5, with chrome highlights, a curvier bonnet (hood) and restyled grille, new alloy wheels and new paint colours.

Inside, there are new trim materials and the rev-counter has been relocated to the central instrument display so that all driving information is in one place.

Technology upgrades include PSA's latest Europe-wide navigation system, MyWay, with high-resolution seven-inch colour screen, Bluetooth and USB connectivity and an audio system with 10Gb hard drive.

European sales start at the end of this year. Right-hand-drive Australia and New Zealand get theirs in mid-2009, according to local importer Ateco.