The Bentley Continental GT Speed Convertible will be claimed as the world's fastest four-seater drop-top when it is displayed at this month's 2013 Detroit motor show.
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The GT Speed Convertible takes the twin-turbocharged 6.0-litre 12-cylinder from its coupe of the same name to reach a top speed of 325km/h.

It accelerates from 0-100km/h in 4.4 seconds, making it just two-tenths slower than the coupe in the benchmark sprint.

The W12 engine in the Speed version of the Continental GT Convertible again has extra power and torque - 460kW and 800Nm, with the latter delivered between 2000 and 5000rpm. This is all sent to all four wheels via a ZF eight-speed auto.

It doesn't use any more fuel than the standard GT Convertible, staying at 14.9L/100km combine for this 4.8m-long vehicle.

Drivers can press a Sport mode button to sharpen throttle response and introduce higher gear shifting points.

As with the coupe, the Bentley Continental GT Speed Convertible sits on 21-inch alloy wheels and a stiffened suspension that has been lowered by 10mm compared with the regular version.

Visually, in addition to the wheel design, the Convertible follows the coupe with a 'matrix' grille and lower front bumper, and 'rifled' dual tailpipes, but is most obviously differentiated by its folding fabric roof.

The Convertible interior also adopts the Mulliner Driving Specification fit-out as standard where it's optional on the non-Speed model.

Expect a price tag close to half a million dollars for the drop-top Speed when it gets to Australia - about a 10 per cent premium over the regular Continental GT Convertible.

Click on the Photos tab for more images of the new Bentley Continental GT Speed Convertible.