Steve Dinan — yes, that Dinan — who still builds race motors for BMWNA through his company CarBahn Autoworks, designed the engine. The S85 5.0-liter mill is bored out to 5.8 liters to return 744 hp and 525 pound-feet of torque on 100 octane race gas, or 5.9 liters to produce 803 hp and 550 hp on 100 octane. They're worked over with Motec engine management, Inconel custom headers and exhaust, and Daley Engineering dry sump lubrication.
They send all their power through a carbon fiber driveshaft to the rear axle only. Straight-cut gears in an Xtrac six-speed transaxle await the ponies, shifts taking less than 20 milliseconds to execute. The "smaller" engine gets a four-year warranty, the larger power plant gets warrantied for two years and needs to be torn down and rebuilt after every 60 hours of running.
Only the acid-dipped and electrocoated tub survives the transition from mildly-powered vintage coupe to monstrous road-legal track machine. The rest is replaced with an alloy frame, safety cage and removable X-bars in the door apertures, carbon fiber body panels, and polycarbonate windows. The length and wheelbase of the donor car hold steady, the roof sits three inches lower but the suspension is height adjustable, and in spite of the fenders gone akimbo, width supposedly grows by just 4.4 inches. Gruppe5 says the aero package delivers 2,400 pounds of downforce.
Riley Technologies, well known worldwide among sports car racing fans, designed the chassis and mechanical bits. A pushrod suspension offers four different adjustments to help keep the rubber on the road. Tires are either Michelin Pilot Sport Cup 2 or Pirelli P Zero Trofeo R mounted on 19-inch, three-piece BBS center-lock wheels hiding Alcon monobloc calipers clamping carbon ceramic rotors.
Inside, Connolly leather and carbon fiber dress up Recaro Pole Position seats and a cockpit. The rear seats have gone, replaced by a fuel cell and air conditioning unit behind a carbon fiber bulkhead. A Motec C187 driver display sits behind a custom 300-mm Nardi steering wheel. Paddle shifters are mounted on the steering column, the wheel holds a nine-position switch to manage front and rear traction. Drivers can also fiddle with the 12-position Bosch Motorsport Cup 5 ABS. Plenty of Dynamat sound insulation helps the original woven carpeting keeps the interior relatively quiet.
The Gruppe5 2002 celebrates the Group 5 BMW 2002 rally racers that AC Schnitzer built in the 1970s, as well as Zajac's former 2002tii race car. The company plans to build just 300 examples, 100 with the 5.9-liter engine, the rest using the 5.8-liter. The junior model will cost $875,000 before options, the 803-hp beast will go for $975,000. The firm plans to build its first prototype after the Riley Technologies chaps return from Le Mans.
Our only reservation about this restomod is that Gruppe5 demands an owner supply a triple-numbers-matching 2002 as a donor car. For a creation that will only save the original car's tub — and gut all of that — it seems a waste of 300 examples of a classic. But hey, any owners with high six figures to spend on the Gruppe5 2002 can decide what to do with their own money.