| The Bentley Continental GTC. The car born to be a convertible. |
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Body Engineering
Chassis stiffening
There was one clear target when Bentley's engineering team began work on the Continental GTC: to create a convertible that drives exactly like its coupé counterpart. By removing the roof - an integral part of the body structure that provides stiffness to the chassis - a convertible has a tendency to shake or vibrate when driven.
Consequently, the Continental GTC's engineers were determined to rid the car of any such 'scuttle shake' and began an extensive development programme aimed at ensuring the Continental GTC's steel body had a torsional stiffness in the region of 30Hz - an incredible figure for a convertible.
To hit that target the engineers added significant steel reinforcement to the sills as well as additional cross braces that run beneath the cabin. Strengthened steel tubing was also used in the A-pillars and windscreen surround. To remove unwanted resonance - as vital a task as ensuring stiffness - a great deal of time was also spent improving the mountings for the rear subframe. Despite the significant reinforcement to the car's body, the weight of the car has risen by just 110kg over the Continental GT coupé, to 2495kg (5500lb). Vibration, too, was eradicated, resulting in exceptional levels of ride and refinement.
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The convertible roof with rollover protection
The second target for the engineering team was to ensure that the car's folding roof was as refined as possible while still fitting into a small stowage area behind the rear seats. Folding flat in just 25 seconds is a remarkable feat in itself for this complex, seven-bow, fabric roof. But just as impressive is its state-of-the-art three layer construction. The Continental GTC's roof has superb acoustic-damping fabrics, with a thicker, more padded outer layer than is used in any other convertible. The 'sandwich' is also a thick, insulating layer while the third inner layer is made from the highest quality cloth material which echoes the roof lining on Bentleys of yesteryear.
Not only are the materials the best available, but the construction and packaging of the roof are second to none. Its designers were keen that absolutely all working parts would be covered, which means that whether you are inside the car as the roof is in operation or watching from the outside, not one piece of the mechanism will be visible.
The roof comes with a heated glass rear window and also an interior rooflamp in the headlining. It can be operated after pulling away from standstill at speeds up to 30km/h (20mph).
To ensure occupant safety, an advanced rollover protection system is installed beneath the rear headrests. If the car's onboard computer senses that the car is about to roll during an accident, two reinforced steel hoops are deployed in a split second, thereby working in conjunction with the exceptionally strong windshield frame to protect passengers in the front and rear seats.
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New rear suspension
To cater for the Continental GTC's sleek design and packaging requirements, a new rear suspension has been created. The convertible shares the same suspension system as its coupé equivalent - a four-link arrangement at the front and a trapezoidal multi-link rear axle with computer-controlled air springs and fully variable, electronically controlled shock absorbers in place of conventional coils.
On previous Continental models, however, the air damper unit was mounted to the upper lever of the rear suspension. On the convertible, the entire damper has been lowered by 210mm and is now mounted to a brand new lower trapezoidal link with an advanced aluminium-cast mounting point that provides the strength and stiffness to hold the damper in place.
With a slightly altered weight distribution and a need to ensure the convertible is as luxurious and comfortable as it is sporting and dynamic, the Continental GTC has revised air spring pistons and damper hydraulics at the front and rear.
As with the other Continentals in the range, the Continental GTC will allow the driver to select from four pre-programmed suspension settings ranging from Comfort through to Sport. These settings automatically adjust the computer-controlled shock absorbers to ensure that the car reacts in the right way to your driving style. At speeds above 152mph (245km/h), the suspension automatically lowers the car to ensure that aerodynamic lift is kept to a minimum, benefitting high-speed stability.
The advanced continuous all-wheel drive system endows the Continental GTC with astonishing traction and poise whatever the weather. In standard conditions the drive is transferred equally between the front and rear axles via a highly sensitive centre Torsen differential. If, however, the differential detects a deviation in torque demand between the two axles it automatically sends more power to the wheels indicating greater grip.
The Continental GTC also incorporates traction control and an Electronic Stability Programme (ESP), both of which can be disabled at the discretion of the driver. Operating discreetly, these driver aids offer additional security and governance over the car's dynamic potential without being intrusive, thereby ensuring the unique Bentley driving experience remains undisturbed.
The Continental GTC shares the revised steering system that was introduced with the four-door Continental Flying Spur. To improve driver feel, friction was reduced in the steering column, rack and suspension ball joints and its responsiveness was also enhanced, with a slightly lighter weighting for more relaxed driving at high speeds while providing a more linear increase in loading as it begins to corner.
In common with its Continental stablemates, the GTC has the largest diameter disc brakes of any series production passenger car on sale today. The front discs are 405mm in diameter and 36mm wide, and the rear discs 335mm in diameter and 22mm wide. The aluminium callipers are branded with cast aluminium 'Bentley' logos at the front.
The braking system features a Bosch anti-lock system with Brake Assist and electronic pressure distribution. The Continental GTC also has an 'intelligent' electronic parking brake with move-off assist (except USA). The parking brake system can also be operated as an emergency brake. In this instance braking is applied to all four wheels and the car's electronic safety systems remain fully operational allowing the driver to steer as normal.
A tyre-pressure monitoring system is standard equipment, and constantly measures the tyre pressures in all four wheels, instantly warning the driver should a significant reduction occur.
"The refinement and dynamics that we have succeeded in engineering into a large convertible are amazing," says Dr Ulrich Eichhorn, Member of the Board, Engineering. "It has the dual character that every Bentley possesses. You can drive along in something that is better appointed than your drawing room and then you can give a supercar a run for its money whenever you want. And when the roads are bumpy and wet who could challenge you with four-wheel drive and incredible grip?"
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Powertrain
The Continental GTC is powered by Bentley's magnificent W12 twin-turbocharged 6.0-litre engine, which will propel the car to 60mph in 4.8 seconds and on to a top speed of 195mph (312km/h). This awe-inspiring piece of engineering is identical to the unit used in the coupé and four-door versions of the Continental and delivers phenomenal power (552bhp/411kW) as well as that legendary wave of torque
(479lb ft/650Nm) from low revs that is the hallmark of every Bentley.
The 12-cylinder block has a 48-valve head with four camshafts that operate using continually variable valve-timing. Power is transmitted via a seven-bearing crankshaft to the car's six-speed automatic transmission. To ensure compliance stringent emissions regulations, the twin turbochargers are designed with a unique bypass valve that automatically sends exhaust gases to heat the catalytic converters when the car is started from cold. This valve then operates as the turbocharger wastegate at all other times.
The Borg-Warner turbochargers are also the ideal solution for producing the flat torque curve, ensuring that the driver has instantly available performance without a hint of turbo lag or having to shift down through the gears. That mighty torque curve is constant, with no drop-off from its maximum output of 479lb ft (650Nm) at just 1600 rev/min all the way up to 6000 rev/min.
The Continental GTC's prodigious power is channelled through a six-speed automatic transmission built for Bentley by ZF. The transmission can be left in fully automatic mode or used as a clutchless manual where gear changes take place only on the command of the driver, via either the gearlever or paddles mounted behind the steering wheel.
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Conclusion
The launch of the Continental GTC means that the Continental range is now complete. Three years after the introduction of the Continental GT coupé, Bentley customers are now able to choose from three remarkable Continentals, all undeniably Bentleys, but all unique in character and appeal.
Bentley Chairman and Chief Executive, Dr Franz-Josef Paefgen explains how each car will have its own unique place in the Bentley stable:
"The proportions of the Continental GTC are the epitome of the elegant, modern convertible and clearly distinguishable from the GT coupé. As the first model in the Continental family, the GT has been responsible for building the Bentley brand across the globe, but it is the Continental GTC that is the most emotional car in the range.
"The GT coupé may be the driver's car and the Continental Flying Spur the more practical four-door Grand Tourer, but the new Continental GTC is the show piece for Bentley design."
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