The Bentley Speed 8 (developed from the Bentley EXP Speed 8) was an Autosport Award Winning Le Mans Prototype race car that was designed by Peter Elleray. The EXP Speed 8 debuted in the 24 Hours of Le Mans in 2001 and won the race in 2003.

It has a strong resemblance to and shares some technology with the Audi R8C, which had raced only once before Audi dropped the project to focus on the later dominant Audi R8. The EXP Speed 8 marked Bentley's return to racing after a 73-year absence.

All design, development and manufacturing for the Bentley was done by the English outfit, Racing Technology Norfolk (RTN), located in Norfolk, United Kingdom. Chief designer was Peter Elleray. Operations for the car were handled by Audi Sport UK, operating under the title of Team Bentley.

The engine from the Audi R8, a 3.6 litre V8 with (Honeywell Turbo Technologies) turbocharger, was used as the initial powerplant in 2001. The six-speed gearbox was also not the typical Ricardo unit from the R8, but instead a custom unit developed by Xtrac. Bentley also chose to run on Dunlop tyres instead of the Michelins used by Audi.

During its run in the 24 Hours of Le Mans race, the Bentleys were the only cars to run in the LMGTP class. Two cars were entered, with one earning third place behind a pair of Audi R8s. The other car unfortunately retired after a strong run in the rain due to a fire which caused the driver to abandon the car.

Bentley returned in 2002, running a lone entry as a testbed for the evolved Speed 8 in 2003, using their new Audi-sourced V8 larger engine. It was modified to better suit the EXP Speed 8 and expanded to 4.0 litres, producing approximately 600 hp. The car managed fourth place, once again behind only R8s.

This would ultimately lead to Bentley redesigning the car for 2003, leading to the change of name to simply Speed 8. The flat front end was replaced with a raised crash box for a nose, while deep valleys ran between the nose and fenders.

This required the addition of large horizontal bodywork between the nose and fenders to shroud the suspension arms of the Speed 8. The cockpit would also be tapered to allow for better airflow to the rear wing.

For 2003, Bentley decided to switch to Michelin tyres, and that their new evolved Speed 8 would need competitive testing in order to prepare for an overall win at Le Mans. The pair of new cars were therefore entered in the American Le Mans Series 12 Hours of Sebring.

Despite having to start at the back of the field due to a rules infraction in qualifying, the two cars quickly made their way through the field. The Bentleys were able to take third and fourth places, behind the factory and a privateer R8.

Returning to Le Mans with assistance from Joest Racing, a Bentley started from pole position. With no works Audi team participating, the two cars were able to lead nearly the entire event, with the #7 entry ahead of the #8, which had some electrical problems during the race.

After 377 laps, the #7 Bentley successfully took the chequered flag, followed by the sister car two laps behind. This helped give the Volkswagen Group their fourth straight victory at Le Mans, split between the Audi and Bentley brands.

It was the last win at Le Mans for a closed cockpit car until Peugeot's win in 2009. Following Le Mans the Bentley program ended, chassis no. 002-3 was last raced at Road America in 2007 prior to the 2012 RM Monterey auction.

A 2003 Bentley Speed 8 competed in 2013 Goodwood Festival of Speed. A 2001 Bentley Speed 8 chassis no. 002-3 was sold to a Japanese collector, then it was subsequently sold to an American collector where it remains today (as of 2009), and was sold in 2012 RM Monterey auction for US$ 2,530,000. It remains the sole car outside Bentley ownership.