Become a Member: Get Ad-Free Access to All Our Content
2008→2008 Porsche/RS-Caldera 9f1 Turbo with active suspension

2006 Radical SR9

2006 Radical SR9

The SR9 is Radical’s first LMP2 car which debuted at Paul Ricard test in March 2006.

The initial concept of the SR9 was a ‘value for money’ LMP2 car that used Radical’s own Powertec RPD 3.0 litre V8, but the company later decided to made proper bespoke racecars that would be individually made for future customers.

This change was motivated by Peter Elleray who came on board and used his experience designing the LeMans-winning Bentley EXP on the SR9. For Radical, he used a completely carbon fibre monocoque that can attach a Judd V8 or an AER Powertec Turbo to the bulkhead, but leaves it unstressed. Power is delivered to the rear wheels through Ricardo’s 750Nm sportscar box.

Radical’s first customer, Rollcentre Racing from the UK helped design and produce the SR9 to replace their aging Dalara SP1 LMP900. Powered by a Judd V8, Rollcentre’s best achievement has been a fifth place at the Le Mans 24-Hour Race. Also present was Radical’s own AER-powered car which placed 15th. Sadly, both teams retired at the 2007 event.

For the 2007 season, Radical made their debut in the American LeMans Series (ALMS) with them Van Der Steur Racing. This team suffered a racing incident during pre-season testing which delayed the debut of the car until the Lime Rock Park.

Story by

In Detail

submitted by Richard Owen
engine AER P07D Inline-4
position Mid Longitudinal
aspiration Garrett Turbo
valvetrain DOHC, 4 Valves per Cyl
fuel feed Injection
displacement 1995 cc / 121.7 in³
power 395.2 kw / 530 bhp @ 7500 rpm
specific output 265.66 bhp per litre
bhp/weight 683.87 bhp per tonne
torque 620 nm / 457.3 ft lbs
body / frame Cabon Fibre Monocque
driven wheels RWD w/Mechanical Plate LSD
wheel type Forged Magnesium BBS
front tires Dunlop
rear tires Dunlop
front brakes Carbon Discs w/Monobloc AP Racing 6-Piston Calipers
rear brakes Carbon Discs w/Monobloc AP Racing 6-Piston Calipers
front wheels F 45.7 x 27.9 cm / 18 x 11 in
rear wheels R 45.7 x 33.0 cm / 18 x 13 in
steering Electrically-driven, power-assisted system
f suspension Double Wishbones w/Pushrod Operated Inboard Adj Shock Absorbers
curb weight 775 kg / 1709 lbs
transmission Ricardo 6-Speed Sequential Transaxle