For the C5 RS6 powertrain detail, the engine is an all-aluminium alloy 4172 cc twin-turbocharged ('biturbo'), double overhead camshaft, 5 valve per cylinder version of Audi's 4.2-litre 90° V8 petrol engine (parts code prefix: 077, identification code: BCY), developed and manufactured in Germany and the UK by quattro GmbH and Cosworth Technology (now known as MAHLE Powertrain).