670-803 hp

459-552 lb/ft

2,200 lbs


Most Powerful, Naturally Aspirated Engine in Production

5.9L CARBAHN S85 V10


91-93 octane gas

670-700 hp*
459-479 lb/ft torque*
200 production limit


100 octane gas 
750-803 hp
430-552 lb/ft torque*
100 production limit

*Performance is based on fuel and map setting.

5.9L-R engine requires 60-hour teardown inspection and refresh.

Carbahn custom S85 5.9L engine built for Gruppe5 Motorsport

  • Steve Dinan S85 is the V10 version of the S65 BMW Daytona Prototype V8 engine.

  • Engines are hand built using race tested components. Each engine is dyno broken in and tested. Results are documented as part of the build. 

  • Daley Engineering integrated dry sump allows engine to be mounted lower in the frame, decreasing the center of gravity and allowing the addition of tuned velocity trumpets to increase horsepower.

  • Engine management is provided by the latest generation MoTec M190 ECU.

  • Custom headers and exhausts are fabricated from Inconel, a lightweight, high-strength alloy that is resistant to corrosion and heat fatigue. Inconel has greater strength than stainless steel and superior resistance to heat and oxidation compared to titanium.

  • Each engine is dyno broken in and tested. Results are documented as part of the build. Engines are signed and numbered by Steve Dinan. 


Riley Chassis

  • Cars are disassembled and all bodywork panels removed. Original steel tub retained.

  • Tubs are trued to original specification, acid dipped and e-coated to protect against corrosion.

  • Alloy frame and safety cage are welded to the tub, reinforcing the chassis. 

  • Carbon fiber laminate assemblies, bonded to the chassis, replace original steel body panels. The result is an extremely rigid and lightweight chassis, capable of handling race stress loads.​

  • Carbon fiber is 50% to 70% percent lighter than steel with the benefit of greater strength, rigidity and superior energy dispersion in the event of an accident.


​Endurance Race Driveline

P1529 Xtrac GT Transaxle

P1254 Xtrac/Megaline

Integrated Valve Actuator

  • Xtrac’s latest GT transaxle is based on the Le Mans winning P529. An advanced rotary ratchet IVA effectuates paddle shifts within 20 milliseconds. “Zero Lash” design allows smoother shifts at part throttle. Xtrem-processed super-polished gear sets reduce surface stress, friction, vibrations and noise. They also offer longer component life. 

  •  Unit weighs 62 kg, half the weight of a dual-clutch transaxle, providing seven times faster shifts and increases horsepower to the wheels.


4-Way Adjustable Pushrod Suspension

  • Pushrod suspension geometry is the gold standard of auto racing. Used in F1, INDYCAR, LMP1 and DPI racing, the load transfer architecture of a simple pushrod is superior to all other suspension designs.

  • Riley Technologies’ pushrod suspension uses adjustable shock absorbers with springs in place of torsion bars.

  • Car height is adjustable within a range of three inches to accommodate different pavement conditions and ride-height regulations. 

  • Riley IMSA design suspension is a collaborative effort between Riley Technologies and JRi Racing Shocks.


Competition Braking and Cornering

Advan A052

Michelin Pilot Sport

  • Ultra-lightweight brake package combines Alcon calipers and Surface Transforms rotors. Alcon billet monobloc 6-piston front and 4-piston rear calipers are among the lightest and stiffest GT calipers, weighing 2.7 kg and 2.8 kg each. Calipers bind continuous-weave, carbon-ceramic race discs (CCM-R), weighing 1.7 kg. Brake combination provides fade-resistant braking while reducing unsprung weight by as much as 70%.

  • Alcon PBA5000 sliding pedal box controls throttle, brakes, and clutch actuation. Combined with an adjustable steering column, system allows multiple preset driver positions, eliminating the need for individual driver seat inserts.

  • 18” BBS RT88-CL 2-piece, DOT approved, forged aluminum wheels are fitted to the 5.9L-S.


  • 18” BBS E07-CL 3-piece, forged aluminum wheels are fitted to the 5.9L-R.

  • The Gruppe5 2002 is equipped with a four-point air jack.


State-of-the-Art Technology

Racetech 119 Series 

W/O-HR Seat

Nardi Custom Gruppe5 Steering Wheel 


C187 Display

Racetech 119 Series

W-HR Seat

Riley Technologies Compact A/C Unit



  • Aria-Group craftsmen provide Concours-quality fit and finish.

  • Interior retains the German minimalist design of the original 2002. Carbon fiber and Connolly leather replace plastic and vinyl. Original woven carpet covers the floor.


  • Used by professional drivers, worldwide, Racetech 119 and 129 carbon-Kevlar seats offer superior ergonomic comfort. Cutting-edge technology includes internal forced-air cooling to the lumbar region. Crafted from a carbon-Kevlar weave, these lightweight seats offer superior comfort and safety.

  • Standard, wide, tall and wide-tall seats are available. 

  • 5/9L-S 119 series seat may be ordered with or without a helmet restraint. Helmet restraint is recommended if the car will be tracked.

  • 5.9L-R 129 series seat is equipped with a helmet restraint.

  • Low base cushions and side cushions are available.     

  • Seats are FIA certified and comply with FIA 8855-1999 standards.


  • Riley electric AC system provides cabin comfort and driver helmet cooling. Electric compressor eliminates parasitic loss to the driveline verses conventional engine-driven compressors. 


  • Modern take on the iconic Nardi wheel of the 1960s, our custom Nardi 300mm wheel is fitted with a carbon fiber switching module and paddle shifters. Steering wheel is secured to the column by a F1 splined, 12-pin quick-release hub.  


  • MoTec C187 multi-page, color display fills the cluster binnacle. Display is programmable to meet clients' individual information needs.


  • Passenger compartment is lined with soundmat to minimize interior noise and harmonics.​


Safety is Our First Priority

  • Safety cage built to meet FIA Appendix J regulations. Removable cage door bars may be ordered. 

  • Bosch Cup 5 ABS system improves limit braking, allowing the driver to brake deeper into corners for faster lap times.

  • GNTX-R Rear Racing Vision System replaces traditional rear view mirror. System increases field of vision by two times. Individual pixel-optimized camera dramatically reduces glare. 

  • Bosh Collision Avoidance System (CAS-M Light) provides driver visible and audible warnings of approaching cars and the side they are attempting to pass on. 

  • Forward-facing MoTec V2 camera records visual and integrated live-time telemetry for steward review.

  • FIA 8855-1999 compliant seats with 6-point harness and driver nets.

  • FIA certified fuel cell, fire suppression and kill switch.


Factory commissioned 1975 BMW 3.0 CSL Gruppe4 Art Car, hand-painted by American, artist Alex Calder.

  • Honoring BMW’s 43-year tradition of commissioning artists to transform factory racecars into functional works of art, clients may work with our in-house artist to create a one-of-a-kind, signed art car.

  • Chassis sourcing is available. Our German colleague has a limited supply of donor chassis,  suitable for remanufacture. Chassis are stripped-down racing 2002s that are structurally sound and will not require major rust remediation.

  •  Additional sets of wheels, tires and Xtrac gear sets may be ordered.

  • Inconel race exhaust, available for 5.9L-R, increases performance and decibel levels. Exhaust may not be legal at noise-restricted tracks. Clients should consult their local track, prior to ordering. 

  • MoTec GPRP-190 ECU provides Level 1 logging and data analysis licenses. Level 2 logging and data licenses are available.​ 

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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 (www.BMW.com). 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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