Engine & Powertrain The new Citroen C5 Aircross SUV boasts of the latest and most fuel-efficient diesel engine. It is mated to a highly refined 8-speed Automatic Gearbox delivering 177 PS of power and 400 Nm of torque for extremely comfortable journeys and maximising driving pleasure. The efficient and refined Stop-Start function is designed for increased fuel efficiency and environmental consciousness. With class-leading fuel efficiency at 18.6 km, the gearbox provides incredibly smooth shifts between gears, making it a real pleasure to drive. The driver can also change gears manually if they want to, using the Steering Wheel Mounted Paddles, shifting seamlessly between Automatic and Manual modes.