THE Discovery's five-cylinder turbo-diesel was under development by Rover before BMW took over operations in 1994. Originally intended to be part of a modular series of engines, the 2.5-litre turbo-diesel was designed for use in the Defender and Discovery models and was the result of an intensive study of the best competitor engines around the world. It bristles with state-of-the-art technology including high-pressure direct injection, overhead camshaft, multi-valve cylinder head and drive-by-wire throttle.