The Audi R8 was initially equipped with a V8 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 cc (4.2 L). It develops a motive power output of 420 PS (309 kW; 414 hp) (Directive 80/1269/EEC), and generates 430 N⋅m (317 lbf⋅ft) of torque, on 98 RON 'Super Unleaded' petrol. It is basically the same engine used in the B7 RS4, but is modified to use a dry sump lubrication system. It uses two chain-driven double overhead camshafts (DOHC) per cylinder bank, and utilises variable valve timing for both inlet and exhaust camshafts. The 4 wheel drive system is biased towards the rear; it sends 30% of its power to the front wheels and 70% to the rear.