Detroit - Bentley Motors unveiled its all new racing prototype, the EXP Speed 8 with which it will return to racing for the first time in over 70 years. The intention is that EXP Speed 8 will set Bentley Motors on a course which will in time lead to outright victory at the world's greatest motor race, the Le Mans 24-hours race. 

A win in this maiden year is not expected. The aim is to finish reliably and acquire data to make the car more competitive for the following years when it will race with its new Bentley engine.
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Tony Gott at the press conference in Detroit

Photo: Automotive Intelligence

The EXP Speed 8

Photo: Automotive Intelligence
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Racing Technology Norfolk (RTN) has been appointed to build the EXP Speed 8 for Bentley Motors, with Peter Elleray heading up the design team. Richard Lloyd's Apex Motorsport with John Wickham as team manager is running the race and test programme. The entire project is being managed by a small team of executives at Bentley Motors in Crewe, headed up by chief executive Tony Gott.   

The Technical Story

The design of the EXP Speed 8 differs from that of all current Le Mans competitors as it will contest the Le Mans GTP class for fully enclosed prototypes. This, says Elleray, brings considerable advantages. "It means we can only use up to14in instead of 16in width wheels but this can be advantageous as they interfere less with the air flow under the car. And we are allowed a 1mm larger air restrictor."

Aerodynamic efficiency lies at the core of the EXP Speed 8's strategy, the closed cockpit making exploitation and management of air flow over the centre section of the car much easier and more effective than on a conventional, open prototype. EXP Speed 8's shape has already been proven in the wind tunnel, where it has been subjected to 11 week long trials featuring over 1000 different configurations tests.

The structure of EXP Speed 8 starts life as three hoops of carbon fibre. Onto this is applied a stressed carbon-fibre skin to create a monocoque that is both strong and space efficient, allowing greater freedom for aerodynamic packaging as well as a more comfortable environment for the driver. This entire structure weighs just 70kgs.

Carbon fibre naturally makes up the bulk of the structure of EXP Speed 8 but the Bentley employs not simply the woven carbon-fibre cloth familiar on all modern racing cars but also uni-directional strips of carbon-fibre in those areas where the forces it is subjected to come from just one source.

The 3.6-litre, twin turbocharged V8 engine has been re-engineered for the EXP Speed 8 particularly to adapt the forced induction system to suit the car's aerodynamics. There are different turbochargers and a new installation while the engine itself has naturally been modified accordingly.

The Bentley specified transverse gearbox has been developed with Xtrac and has six speeds and pneumatic gear engagement for extra speed and reliability over 24 hours. This gearbox has been designed specifically to cope with the characteristics of EXP Speed 8.

The suspension follows current race car thinking with double wishbones at each corner. Even so it uses torsion bar springing at the front as they package into the EXP Speed 8's design without disturbing the crucial air flow under the front of the car. Coil springs are used at the rear.

The brakes have been developed with AP Racing and feature carbon discs and pads, with six piston callipers at each corner. The tyre supplier is Dunlop on whose rubber the winning Bentleys of the twenties and thirties raced, thus renewing a 70 year old partnership.

(Jan. 9, 2001)