Tech analysis: Bentley Continental GT3

A few years ago, when people thought of Bentley Motorsport, they either had images of guffawing moustached gentlemen steering a behemoth vintage car at the old Circuit de la Sarthe, or the sexy and sleek and streamlined Speed 8 prototypes of the early 2000s that brought them their sixth Le Mans victory.

Today, if you mention ‘Bentley Motorsport’ there’s increasingly good odds that people now think of well-groomed gentleman guffawing in a much newer behemoth racing machine: the Continental GT3.

Debuting in the 2014 Blancpain GT Series, the Continental GT is Bentley’s unlikely modern war-machine. It looks as large as a main battle tank and it echoes a WWII fighter plane roaring past. In recent years, it has expanded its theatre of operations across the globe; the Continental has now featured in the Pirelli World Challenge, the Nürburgring 24 Hours, the Bathurst 12 Hours, Super GT, and the Sepang 12 Hours.

While Bentley’s choice of the portly Continental platform still polarizes racing fans, the amount of work that went into turning a 2.3 tonne vehicle of opulence into a competent GT3 racer is worthy of nothing but admiration. To perform this task, Bentley partnered with M-Sport in the UK of World Rally Championship fame, which took to the car with a clean-sheet perspective.

Body

The Continental is one the largest of the GT3 racers courtesy of its base chassis: a road-going steel monocoque. It is required to be used due to the FIA GT3 regulation. The Bentley design utilises a fair amount of the exterior panelling to absorb the stresses of road use, and allows for the reduction in overall material required. It provides a great starting point for building a racing car.

Empty shells are shipped to M-Sport for fit out, and the mass of parts from the 2.3 tonne road car that don’t make it into the race car is quite staggering; such is the quest for speed.

The road cars 4WD system is the first thing to be omitted–GT3 is RWD only. All the luxury parts; leather, wood trim, double glazing, numerous electronic controlled gizmos, et cetera, are all kept out for more spartan options such as plastic windows, untrimmed carbon fibre and room for just the one occupant. The floorpan of the car is modified to allow for the access to the transaxle, among other things.

Up front, the Continental’s nose is overhauled significantly. The front wheel arches are re-skinned in all-new, flared out carbon panels which widen its front stance and track significantly. This is done to match the rear, where the guards appear to be slightly flared out to fit wider race rubber. Capping off the front is a full-carbon bonnet, complete with deep racing vents.

Other panels getting the full-carbon treatment are the boot lid and the doors. The doors are a very notable item because the race versions–in full-carbon–weight just 7 kilogram each, compared to the trimmed-out road cars’ 57 kilogram items.

Under the skin many changes have been made, with stiffening braces added in combination with the car’s new FIA specification roll cage that has been welded-in throughout the shell and provides the driver with a high level of safety as well as doubling the chassis stiffness.

With these modifications and race parts fitted, the Continental GT3 weighs in at a touch less than 1,300 kilogram. That’s an impressive whole tonne less than the road car.

Rolling, bumping and stopping

The Continental GT3 touches the racetrack on a uniform set of 310/710-R18 tyres, which are wrapped around 11 spoke O.Z. Racing 18 inch diametre x 13 inch wide rims. Suiting GT3 regulations, these are secured to the race-specific machined uprights via a centre lock hub.

Stopping duties for the beast are performed by a full Brembo brake system, with slotted steel rotor discs. Front wheels are served by six piston calipers, the rear by four. As per all other modern GT3 cars, the brake bias is fully adjustable via the driver controls, as is the multi-point ABS system that helps extract more consistent performance for the car’s gentleman drivers.

Cooling air for the front rotors is fed from front intakes located under the car’s headlights. This is fed via ducting to the wheel turret where it is channelled directly to the discs for optimised cooling.

Keeping everything in contact with the tarmac are Öhlins TTX four-way adjustable dampers front and rear, paired with double wishbone suspension.

Power and Transmission

The engine bay is another area that M-Sport and Bentley looked at thoroughly for optimal performance gains.

Although the road-going Continental is famous for its VW Auto Group derived W12 engine, in a balanced endurance racing formula that is not necessarily a good thing. After some deliberation, the GT3 Continental was fitted with an Audi-sourced 4.0 litre twin-turbo V8 (don’t forget: the last time Bentley took an Audi V8 and put it in their racing car good things happened). The reasons for this were quite simple: the new powerplant weighed 23 kilogram less than the W12, it was more compact so it could be placed in a better location, and it was more fuel efficient. Furthermore, it could also easily put out the 500 to 600 horsepower required to cut it in GT3 circles before Balance of Performance is applied.

The result is a smaller powerplant that allows it to be positioned way back within the cavernous engine bay–sitting behind the front wheel centre line. With the addition of a dry-sump oil system, the motor can also be seated far down for optimised centre of gravity for the whole car. The turbos for the motor are taken out of the vee, where they live in road car configuration, and placed down low within the bay for improved centre of mass–but also mainly because the new engine bracing squeezes them out.

It turns out that even with the smaller block engine, scant few seem to mind. Equipped with a distinct V8 burble that gets better the longer the throttle is held open, the roar of the car has become a crowd favourite.

To help with the weight distribution, the gearbox finds itself also being squeezed out of the engine bay and moved to the rear transaxle. The result is a 52:48 front to rear balance. The gearbox in question is an X-Trac six-speed, pneumatically controlled sequential unit complete with a reverse gear, and it is mated to the engine via a full-carbon prop shaft.

Gear changes are commanded by the driver via gear shift paddles located behind the steering wheel, which send electrical signals to an actuator on the gearbox, triggering it to make super-quick gear changes. The paddles themselves are a take-off from the Bentley Mulsanne road car, because Bentley believes a little bit of luxury should make it to the track–it’s in their DNA.

Cooling for the mechanical gear appears to come from two locations. On the front of the car, the front mesh grille serves as the engines air intake complete with air filter. Beneath this, the larger lower tunnel serves the radiator, and the bottom most central slots feed air to the intercoolers. One last air ‘scoop’ is located on the rear boot lid, and funnels air to a carbon duct located in the boot space. This splits air flow to an oil cooler that serves the transaxle, and the rear brake discs.

Aerodynamics

A car with such a large frame seems to be at an aerodynamic disadvantage compared to the sleek sportscar based models from Ferrari, McLaren and Porsche to name a few, but M-Sport engineers have performed a significant amount of CFD-based development that has helped hone the Continental’s aero profile into something competitive.

First point of design in the car’s aero armada is the front splitter. While extending the length of the Continental from 4.8 metre to 4.95 metre, it also performs a balancing act of trapping or diverting the air that the car is pushing through. The task of the splitter is to ‘trap’ air on its top side, against the front of the car. This air tries to expand and by doing so pushes down on the lip, and creates downforce. Higher speed incoming streams of air are forced around this stalled pocket, ending up either being channeled under the car–which is helped by a slightly raised tunnel section–and activating the car’s flat floor for more downforce, or forced over the car, where it flows tidily over the cabin.

Other little aero tricks located on the front bumper include some small dive planes to help add a little more downforce, and aerodynamic ducting that houses the cooling equipment. The shape of the ducting helps ease the cooling flow back into the main stream of flow to minimise disruption and retain efficiency.

Running along the sides of the car are some well blended side skirts, which house the exhaust outlets that appear just behind the driver door. These skirts help keep airflow running over the sides of the car from spilling over to the underside the car, affecting the flat floors efficiency.

At the back of the car, a gigantic GT3 spec rear wing helps keep the car pushed to the ground. It is mounted via a set of ‘swan neck’ stanchions. The wing is a single chord type. Angle adjustability of the wing is made via its top-side mounts, with the endplates also being tilt adjustable to suit.

Tucked-in underneath the rear of the car is a large rear diffuser, which draws air from the flat floor. It is one of the tallest in the GT3 field, with four carbon strakes making three very distinct tunnels.

Other little aero trickeries include slightly reduced aero profile mirrors which retain some of the appearance of the road car’s items.

Interior

The Continental GT3’s interior is almost a complete contrast to its road-going form, save for a few small luxuries.

Absent are the road car’s opulent, deep seats with massaging capabilities. These are discarded for a singular, race-specific Sparco carbon item that comes complete with six-point racing harness. Some of Bentley’s luxury signature is applied to this, with a hand-stitched GT3 logo added onto the seats fabric.

Beyond this, though, is the bare minimum of luxuries–everything else is sacrificed for racing. The inside of the bare shell is nearly unrecognisable without its woodgrain, leather and carpets. In place of the passenger seat where model WAGs would be seated is a fire extinguisher and ECU module. The deep mahogany woodgrain of the dash panels is also absent, replaced by a silhouette crafted in 3k carbon. Air conditioning makes the cut–but mostly because FIA cabin temperature rules require it. Nothing superfluous is added.

Some could see the absence of luxury as an eye sore, but there is some sexiness to the pure finish of a racing interior. Take for instance the steering wheel, which has been whittled down over the years since the GT3’s introduction. Its small size seems out of place within the cavernous Continental, and the mind boggles how it can cause such a brut to steer nimbly. The compact form offers everything the driver needs, right at their fingertips on a carbon-face plate. Twelve ABS, eight traction control and eight engine map settings are controlled by dials here, as are the display pages for the dash. Also included are pit limiter, neutral, light flash and radio, among others.

Behind the driver sits the fuel cell; an FIA specification item for extra safety in the event of an accident. In all four corners of the cabin are the GT3’s air jacks for lifting the car in the air quickly for servicing. It’s all racing in here.

One last detail makes the Continental GT3 more unique to all others on the grid: the driver sits on the right-hand side. Why is that so? Well good sir, it’s because Bentley is a proper British car.

Future

Bentley’s first foray into GT3 racing has undoubtedly raised the performance appeal of the Continental GT model, which is typically recognised as a two-door luxury vehicle first and foremost.

For technical partners M-Sport, this adventure into the sportscar world has also paid off. Such an immensely challenging platform demands first-class engineering expertise, which they capably translated from their rallying background.

The result for both has been a successful customer car, with Continentals now operating for teams based in China, Australia, Britain, Germany, the USA and, more recently, Japan–all despite their lofty price tag.

The next generation of Continental is due 2018, with a new GT3 model due very shortly afterward.

How many of the lessons learnt from the GT3 project will be used to improve the new car remains to be seen–but, reportedly, the test mules are already significantly lighter courtesy of a switch to an aluminium chassis.

With significant regulation changes made since the Continental GT3’s launch, it will be exciting to see what the next clean-sheet iteration will bring to racetracks the world over.

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Stuart is a fan of racing on four wheels as well as two. He was bitten by the Sportscar bug as a kid in the 90's, which inspired him to become a Mechanical Engineer. He enjoys studying the craft and design behind the top racing machinery, heading to the track, and tinkering in the garage where he usually has something going on.

Stuart Bowling

Stuart is a fan of racing on four wheels as well as two. He was bitten by the Sportscar bug as a kid in the 90's, which inspired him to become a Mechanical Engineer. He enjoys studying the craft and design behind the top racing machinery, heading to the track, and tinkering in the garage where he usually has something going on.