It's their own bespoke design; took years of development and testing. Apparently 45kg lighter than the flat-6 and lower center of gravity. Sounds awesome, too:
Body:
2 seated coupé with integrated roll-cage
2 racing type bucket seats
Aluminium doors and front hood
Carbon fibre engine cover and rear spoiler
Engine:
Lightweight-8-Cylinder-90°-engine with racing DNA
180° crankshaft “Flatcrank”
4,5 Liter displacement
Power output 404 kW (550 bhp) @ 8500rpm
Maximum torque 500 Nm @ 5400rpm
Aluminium crankcase and cylinder heads
Water cooled, cylinderheads and engineblock cross flowed
4-valve system with spherical layout
4 camshafts with hydraulically timed valve system for in- and outlet
Hydraulic valve tappets
Dry sump oil lubrication with two windage trays for each of the 4 chambers
Individual chamber oil suction with 2 suction intakes
Waterpump, generator and AC compressor are directly driven of the Engine (no belts), located at the lowest position
Sequential fuel injection system
Individual cylinder ignition coils
Electronic engine management system
Electronic throttle control system per bank with 2 butterflies
3-Way catalytic converters with stereo closed loop lambda control
On-Board-Diagnosis for continuous monitoring of the exhaust system
Transmission:
Rear wheel drive with 6 speed manual gearbox
Chassis:
Electronic stability control system, ABS, traction control,
automatic limited-slip differential
RUF high performance brakes with ceramic discs,
perforated and air cooled
Front brake disc diameter 380 mm
Rear brake disc diameter 350 mm
Forged RUF alloy wheels with single central retaining nut
Front : 9Jx19 with 245/35 ZR 19
Rear : 12Jx19 with 325/30 ZR 19
Michelin Pilot Sport Cup tires
All specifications are subject to variation, as specified for the prototype RUF RGT-8