The Apollo uses a 4,163 cc bi-turbo intercooled version of the Audi V8 engine. The 90° V8 has a closed-deck light metal crankcase with dry sump lubrication. The light metal cylinder heads have five valves per cylinder, four overhead camshafts, VarioCam Direct variable valve timing on the intakes, and hydraulic valve clearance compensation. The double-flow exhaust system has four oxygen sensors to monitor the gas mixture, and a 3-way catalytic converter. Modern controls include an on-board diagnostic system, eight-coil electronic ignition, sequential multipoint fuel injection, and an electronic (drive by wire) accelerator system. Optimised engine control, new recirculation valves and improved cooling have now improved the performance of the German Altenburg-built racing car to 750 hp/551 kW (previously 700 hp/515 kW). This increase in performance of more than seven percent can be felt above all on curved and fast stretches of road. The power per litre therefore increases to more than 180 hp per litre of cylinder capacity.