The impressive fuel economy for such powerful cars is attributable to the combination of the XK range's lowest-in-class weight and the all-new AJ-V8 Gen III engines. As well as the intrinsic advantages of the engines' light weight, these advanced all-aluminium four-cam power units have a number of features that deliver power with very high efficiency, including spray-guided direct injection (SGDI), which improves performance and economy, and dual independent variable cam timing (DIVCT), which benefits performance and economy, while also reducing emissions.