Mercedes-Benz 500I engine

The Mercedes-Benz 500I was a turbocharged 3.4 litre Indy car V8 designed, developed and built by Ilmor in partnership with Mercedes-Benz for a single purpose, the 1994 Indianapolis 500. It was developed in secrecy for Team Penske, at first under the name Ilmor 265E, as a 209 cubic inch purpose-built pushrod engine that exploited a provision in the Indianapolis rules meant for stock block pushrod engines, which allowed extra displacement and turbocharger boost compared with the 2.65 litre racing V8s. Its reported output was around 1,000 horsepower, an advantage of 150 to 200 horsepower over conventional V8s, and Mercedes paid a fee near the end of development to badge it. Fitted to the Penske PC-23, it helped Team Penske dominate the month and the race, which Al Unser Jr. won after teammate Emerson Fittipaldi touched the wall late on. The engine was slightly lighter than the 265D it replaced, although its longer inlets raised the centre of gravity.