Radical Sportscars LeMans Prototype SR9



Following on from the success of the SR8 and RPE V8 engine, in 2006 Steve Prentice Design helped Radical to design their next car, the SR9, an LMP2 class car to compete in the LeMans 24 hour race.





Chief engineer and aerodynamicist for the project was Peter Elleray, who had designed the 2003 LeMans winning Bentley.

Steve Prentice Design were responsible for design of the engine installation for both Judd 3,4 litre V8 and AER 2,0 litre turbo versions. This included:

  • engine mountings

  • bell housing

  • clutch

  • starter

  • oil system

  • coolant system

  • intake system

  • exhaust system


The first car was built for Rollcentre Racing using the Judd V8 engine. Driven in 2006 LeMans 24 hour race by Martin Short, Joao Barbosa and Stuart Moseley. After 6 hours of the race they were second in P2 class, 7th overall, an amazing performance. But problems struck during the night with long delays for repairs to a leaking cylinder head and then a worn out clutch. They finished 5th in P2 class, 20th overall, which was a disappointing result for such hard work put in by everyone at Rollcentre Racing.


The Rollcentre team were filmed at LeMans by John Matthews, his film LeMans: in the Lap of the Gods really captures the atmosphere of working on these cars better than any film we’ve ever seen. Buy it at Duke Video.




Further cars have been built using the AER engine for Bruichladdich-Radical, the works race team, and other customer race teams. SR9s had podium finishes in the LeMans Series races in 2006 and 2007 and won the Michelin Green X Challenge, for most fuel efficient car, at Barcelona in 2009.


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