This leviathan of a motor has been thoroughly revised at the top end to produce and extra 25bhp, making 530bhp in total. Which doesn't sound all that significant until you realise what's happened to the torque peak, and to the way the torque is delivered.
Maximum pulling power has risen from 752lb ft to a vaguely terrifying 811lb ft – but of arguably more significance is the fact that this peak figure now registers at just 1750rpm, and it stays pretty much flat between there and 4200rpm. The previous engine's peak figure wasn't attained until 2250rpm, and in that case it really was a peak.
In reality, then, the Speed should feel much torquier and, therefore, be much faster than the Mulsanne, hence the reason why Bentley now quotes some fairly hair-raising acceleration figures for the car. Zero to 60mph takes a mere 4.8sec, zero to 100mph 11.1sec, and the top speed is a deliciously irrelevant 190mph. This has enabled Bentley to claim that the Mulsanne Speed is 'The fastest luxury saloon in the world.'
Quite what owners of a Mercedes S63 AMG would make of such a claim isn't clear but, either way, the Speed is an indecently rapid machine considering it mauls the scales at a fulsome 2685kg.
Not only is the engine more potent but, as is the requirement nowadays from all cars, from all creeds, it's also cleaner and more efficient than before. Emissions and economy have both been improved by around 13 per cent. In the real world Bentley claims the Speed is 2-3mpg less thirsty than a regular Mulsanne.
Elsewhere, the air suspension has been recalibrated to deliver more sporting responses when Sport mode is selected within the new Drive program. The same goes for the steering, the eight-speed ZF gearbox and the throttle mapping: each of these can be set to whatever individual mode a driver might want by selecting the Custom function.
So you can have the dampers set to Comfort, the Steering set to Sport and the powertrain set to standard, or any other combination. Which is nice.
Then there's the most vital area of all in a Bentley; the cabin. For the Speed there are various new sporting touches that have been unleashed inside. The door caps now feature small amounts of tastefully applied carbonfibre trim. The seats feature colour-coded stitching in their leather and diamond quilted hide on their backrests. The door handles have been 'coin' finished and, whisper this, the foot pedals are now made from drilled aluminium alloy.