2015 Bentley Continental GT Speed Specification - Bentley’s iconic 6.0-litre twin-turbo W12 engine has been pushed even further, now developing 635 PS (626 bhp / 467 kW) and a record 820 Nm of torque. The new Bentley GT Speed coupe reaches a top speed of 206 mph (331 km/h) – the fastest production Bentley ever – while the revised convertible can reach 203 mph (327 km/h).