Build #0003 aka “LUTHER”
In 1974, the FIA required a Group 5 engine displacement limit of 3.0 liters while instituting a multiplier factor to account for the additional power that turbocharging systems began to develop. From here, Porsche factory race engineers Hans Mezger and Valentin Schäffer developed a 2.142cc engine, establishing cylinder bore at 84mm and stroke at 65.2mm. Similar to the Can-Am and European Interseries 917 models, the new engine was mated to a single KKK turbocharger. By the end of the ’74 season, this combination was reliably producing 500hp at 7600 rpm.
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This unique factory race car saw only limited track exposure, despite the formative intersection of the famous RSR’s, IROC 911’s and 930’s that followed. This inspired the Accumoto team and thus hatched the idea to pick up where the factory might have gone, had development of the “Baby 935” continued.
Albeit with a twist…
Accumoto Build (#0003) was created from a 1984 G-body Carrera. This exceptionally clean donor chassis was stripped to the bare metal tub. Extensive metal work was conducted to create the hood center-fill, sunroof/rocker trim delete, torsion tube back-date and facilitate the addition of a larger front oil cooler.
The engine has an interesting back-story as well. Beginning with a 1968 magnesium case, Accumoto used the same bore and stroke that Mezger and Schäffer utilized, resulting in 2.1 liters which was then augmented by twin K16 turbochargers. This block was then married to a 1974 RSR bodied tub and campaigned by Accumoto Motorsport in the Porsche Club of America’s racing program. Driven by Accumoto’s proprietor, the team captured multiple track records and overall wins at Sebring, Watkins Glen, Road America and Brainerd International Raceway. With development complete, the engine was disassembled and entirely refreshed. In anticipation of installation into Build #0003, it was mated to a shortened short-ratio G50 gearbox. This combination achieves 297hp @ 0.5 bar, 334hp @ 0.7 bar and 364 @ 0.9 bar at the wheels on 91 octane pump gas.
The platform is supported by triple adjustable Accumoto/JRZ shocks riding on Accumoto three piece 911 wheels with 930 calipers. Multiple proprietary touches include the front and rear bumpers, roll hoop, re-shaped intercooler and hand-formed deck-lid grill. These work in concert to convey the level of detailed fabrication that permeates Build #0003.