 The four-cylinder P41 was based on the structure of AER's 3.6 liter twin-turbo P32T V8 engine.In 2010 the P41 was replaced with the new P70 with a new block and cylinder head and increased power for use in LMP1.The engine represented the state of the art in turbocharged engine technology and was designed for the rigors of a 24-hour race.