The Audi R8 was initially equipped with a 4.2 litre V8 internal combustion engine. Specifically, it is an all-aluminium alloy 32-valve (four valves per cylinder) petrol engine, utilising Fuel Stratified Injection (FSI), and has a displacement of 4,163 cubic centimetres (254.0 cu in). It develops a motive power output of 309 kilowatts (420 PS; 414 bhp) (Directive 80/1269/EEC), and generates 430 newton metres (317 ft·lbf) of torque, on 98 RON 'Super Unleaded' petrol. It is basically the same engine used in the Audi B7 RS4, but is modified to use dry sump lubrication system. This V8 is a highly reworked, high-revving variant from the existing 4.2 litre V8, but includes cylinder-direct fuel injection (Fuel Stratified Injection), and four valves per cylinder, instead of five (as used on the previous non-FSI variants). It also uses two chain-driven double overhead camshafts (DOHC) per cylinder bank, and utilises variable valve timing for both inlet and exhaust camshafts.