Powertec RPA is the name of a V-8 engine developed by Radical Motorsport in Peterborough England. The design is loosely-based on the 1.3 liter I-4 engine produced by Suzuki for their Hayabusa motorcycle. The company have designed their own engine block and use existing Suzuki cylinder-heads . The two heads are joined at a 72-degree angle. Lubrication is provided by a dry-sump system. The engine will be mated to a purpose-build transaxle designed by Quaife.
Ultimately, three versions of the engine are planned: the original 2.6 liter model which retains the original bore and stroke of the Hayabusa design, a de-stroked 2.0 liter for higher peak output and a stroked 3.0 liter which sacrifices peak power for higher torque at low revs.
Specifications
(from Radical Motorsport)
- 72° V8 cylinder
- 32 valve quadcam
- Power 350 to 400 bhp (260 to 300 kW)
- Maximum revs 10,500 rpm (2.6 litre) / 12,500 rpm (2.0 litre)
- Bore 81 mm
- Stoke 63 mm (2.6 litre) / 48 mm (2.0 litre)
- Compression ratio 11.0:1
- Steel flat-plane crankshaft
- Twin counter-rotating balance shafts
- Twin pump lubrication system
- Four scavenge pump dry sump system
- Rotary vane coolant pump
- Pre-engage starter motor
- Belt-driven 45 amp alternator
Dimensions
- Length: 546 mm
- Width: 513 mm
- Height: 440 mm
- Dry weight: 92.6 kg
Bellhousing/clutch
- Single plate dry clutch
- Optional twin plate dry clutch
- Integral oil tank capacity 9 litre
- Integral rear engine mount
- Engine - gearbox spacing 126 mm
- Dry weight 13.7 kg
Transaxle
- Six-speed constant mesh
- Sequential shift 1 forward, 5 back
- Gear ratios
- 1st 2.615
- 2nd 1.937
- 3rd 1.526
- 4th 1.285
- 5th 1.136
- 6th 1.043
- Overall reduction ratio 3.400:1 to 5.670:1
- Reverse gear ratio 3.000:1
- Torque biased limited-slip differential
- Integral oil cooling pump
- Pressure fed lubrication system
Dimensions
- Length: 393 mm
- Width: 300 mm
- Height: 365 mm
- Dimensions from mounting face to drive shaft centre: 128 mm
- Dimensions from front of engine to drive shaft centre: 800 mm
