The 4.2 TDI took the place of the four-liter unit in 2005. With its initial 240 kW (326 hp) output and 650 Nm (479.41 lb ft) of torque, the V8 was a supreme power unit for the A8 and the Q7 which followed in 2006. At around 250 kilograms (551.15 lbs), the eight-cylinder unit was relatively lightweight. With an overall length of 520 millimeters (20.47 in), it is also exceptionally compact. Over the years its power output has been increased to 283 kW (385 hp) in the A8 and 250 kW (340 hp) in the Q7.