Anatomy of the CarBahn S85 Gruppe5 2002 Racing Engines 


Steve Dinan has been building high performance and racing engines for BMWs since 1977.  He’s won 11 racing championships including three Prototype Championships and two Rolex 24 Hours at Daytona races. 
CarBahn S85 5.8L and 5.9L engines, built for the Gruppe5 2002, are full blown racing engines hand built at our shop by a group of talented engineers, machinists and builders. 
The CarBahn S85 engines are not the same as the old Dinan Stroker engine.  They are based on our S65 prototype engine that we ran in the Ganassi DP car.  


Gruppe5 2002 engines have:

  • A special crankshaft with journal sizes changed to accept Clevite racing bearings for improved durability.

  • Longer rods to reduce side load and enable higher RPM

  • Low friction 2-ring pistons

  • Low friction piston rings

  • Racing cylinder head work

  • Dry sump  

  • Carbon fiber inlet plenum with tuned carbon fiber trumpets  

  • On the race version, there is also a racing camshaft like the one used in our prototype engine. 

These engines employ all the technology that we have acquired over the years in motorsports. 

Steve Dinan

CarBahn Autoworks  

May 14, 2019

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Gruppe5 Motorsport (Gruppe5) reengineers and retrofits clients' licensed BMW® 2002 automobiles. Gruppe5 does not manufacture or sell automobiles. Gruppe5 is not sponsored, associated, approved, endorsed nor, in any way, affiliated with BMW of North America, LLC, or Bayerische Motoren Werke AG ( The BMW® name and Roundel are trademarks of Bayerische Motoren Werke AG.  Gruppe5 is not sponsored, associated, approved, endorsed nor, in any way, affiliated with D Dinan® or Dinan Engineering, Inc. The D Dinan® name and logo are trademarks of Dinan Engineering, Inc. and any other products mentioned are the trademarks of their respective holders. Any mention of trademarked names or other marks is for purpose of reference only.

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