S65 4.1L Supercharger/Turbocharger Engine

Steve Dinan has been building high performance and racing engines for BMW’s since 1977, winning 11 racing championships including 3 prototype championships and two 24 Hours of Daytona. The same engine shop that builds the racing engines also builds the street car engines; these talented engineers, machinists, and builders have built hundreds of engines from OEM street rebuilds to full-blown racing engines.

The CarBahn Autoworks S65 4.1L bored engine is built featuring high performance over-sized forged pistons, a forged crankshaft with stock stroke, and high-strength forged Carrillo connecting rods. The bore is increased to 92.5 mm.

We do a complete rebuild that increases power and improves durability with Clevite-CarBahn racing rod bearings, CarBahn Autoworks valve springs, an MLS (Multi-Layer Steel) head gasket, a valve job with new hydraulic lifters, plus timing chains, timing chain guides, timing chain tensioners and all associated seals and gaskets.

To facilitate more boost, the engine has been re-engineered to be a forced induction engine with lower compression, more crown height to dissipate heat, thicker rings, and stronger connecting rods. The engine can be purchased in 3 compression ratios: 10:0-1, 10.5-1, and 11:0-1.

Engine core acceptance parameters

Must be complete core (factory engine, from oil pan to valve cover)

• Block must have no:
  • Holes or cracks in casting
  • Holes or crack in covers
  • Bore damage that cannot be honed out
  • Thrust surface damage
  • Journal surfaces damage
  • Bolt hole damage that can’t be repaired
• Heads must have no:
  • Holes or cracks in casting
  • Holes or crack in covers
  • Thrust surface damage
  • Journal surfaces damage
  • Bolt hole damage that can’t be repaired
• Additional repair charges could apply for damaged items that are not normally changed during an overhaul and cannot be repaired or serviced
  • Valves
  • Crankshafts
  • Camshafts
  • Guides
  • ValveTronic mechanism
  • Vanos mechanism