2007 Radical SR8LM review

Radical SR8LM review:

Already the fastest prototype on the club racing scene and with the Nürburgring Nordschleife lap record to its name, Radical’s SR8 is now available with a more powerful Powertec V8 motor and an all-new Powertec transaxle.

The SR8LM, as the car is to be known, is powered by a 2.8 litre, 455bhp Powertec RPB motor which is based on the hugely successful 360bhp RPA motor. Like the RPA, the RPB utilises Suzuki GSXR 1300 cylinder heads mated to a Powertec designed and manufactured crank case assembly. Weighing in at only 88kg the RPB engine incorporates a four-pump dry sump system with two oil pressure pumps and integral rotary vane water pump. Powertec uprate both the cam shafts and cylinder heads and fit purpose-designed forged pistons and conrods. The twin-butterfly plenum induction system of the RPA is replaced with an eight-butterfly direct injection system, which dramatically improves response and drivability. With 30 hours between rebuilds, the fully warrantied RPB gives exceptional value as well as power.

Radical have also installed an ‘in-house designed’ Powertec P-tec six-speed transaxle which transmits the 455bhp and 10,500 maximum rpm of the Powertec motor to the circuit. Gear-change is via Radical’s own paddle-operated power shifter which allows flat shifts going up the box and automatically ‘blips’ the throttle going down. A considerable amount of work has been carried out to match the Powertec P-tec transaxle with the pneumatically-operated Powertec PS1 shifter.

The result of all this technology is a car capable of matching a Le Mans prototype around most circuits, hence the ‘LM’ designation. Radical co-founder, Mick Hyde elaborates, “Many of our customers world wide, race their Radicals in multi-make sports car series and require a car that will beat all-comers. The SR8 is that car. It is the fastest off-the-shelf sports racer in the world (actually it takes six weeks to build one) and at £89K ready to race, the SR8LM is also extremely good value.”