2007 Bentley Arnage R

2007 Model Year Bentley Arnage

Bentley Motors continues the intensive development of its flagship Arnage range with the introduction of a major programme of powertrain and chassis enhancements for the 2007 Model Year. The Arnage's renowned 6.75-litre V8 engine now develops up to 500bhp and is mated to a six-speed automatic transmission benefiting performance, driving dynamics and refinement. The powertrain changes are complemented by subtle exterior, interior and under-bonnet design cues.
Key to this performance increase is the most powerful version of Bentley's legendary V8 engine ever built at the company's headquarters in Crewe, England. In the performance-oriented Arnage T model, the revised twin-turbocharged V8 engine produces a staggering 500bhp and 1000Nm of torque – an 11percent increase in power and a 14 percent increase in torque over the outgoing model. Twinned with the latest six-speed ZF automatic transmission, which uses state-of-the-art computer management, performance and refinement are optimised at all speeds. In the Arnage R and RL models the new engine is boosted from 400 to 450bhp, while torque climbs from 835 to 875Nm.

'The 2007 Model Year Arnage range is clear evidence of our intent to ensure Bentley's flagship model remains at the forefront of technology and delivers the performance, refinement and luxury that every Bentley customer demands,' explains Stuart McCullough, Member of the Board, Sales and Marketing.

'Two years ago we introduced major upgrades to the Arnage's chassis, steering and brakes,' says Dr Úlrich Eichhorn, Member of the Board, Engineering. 'Those improvements meant the car could easily handle a significant increase in power and torque, so work began on this important powertrain programme.'

The 2007 Model Year Arnage also benefits from safety, interior and design improvements. Every Arnage now has a Tyre Pressure Monitoring System, rSAP Bluetooth integrated telephone system and improved driver ergonomics as standard. Additionally, new wheel, exterior paint colour and interior trim options are available, as well as an optional retractable ‘Flying B' bonnet mascot.



Engine
Bentley's 6.75-litre V8 engine is the centrepiece of the 2007 Model Year Arnage development programme. This remarkable engine, the fundamental design of which has served Bentley models proudly for nearly five decades, has been extensively re-engineered to provide, in Arnage T specification, 500bhp and 1000Nm of torque - figures that ensure that the legendary Bentley wave of torque is even more astonishing than before. Top speed of the Arnage T has risen from 168mph/270km/h to 179mph/288km/h, while the 450bhp Arnage R and RL's maximum speed increases by 13mph/21km/h to 168mph/270km/h.

When the first V8 engine was built in the 1950s, the design brief unwittingly benefited later generations of Bentley engineers. It was a very forward thinking design with an all-aluminium construction, a five main-bearing crankshaft, and a well-supported camshaft. The steps taken then laid the foundations for the longevity of the engine.

'People might raise an eyebrow when they are told that the V8 engine in their 2007 Model Year Arnage was first used by Bentley in 1959,' says Bentley Motors' Director, Powertrain and Chassis, Brian Gush. 'But the reality is the basic design was so good that we have been able to continually improve it for nearly 50 years.

'One of the reasons the engine has evolved so successfully is the position of the exhaust valves, high in the cylinder head, originally designed for rapid heat dissipation to help engine cooling. Decades later it meant that we could heat the catalytic converter due to the short path from valves to catalysts, which benefits exhaust emissions. This is just one of the reasons why this brilliant engine lives on today.'

That first 6.25-litre engine produced around 200 horsepower – the new 2007 Model Year 6.75-litre V8 has more than twice that output, with 500bhp and 1000Nm of torque for the Arnage T. It was the introduction of turbocharging and intercooling in the early 1980s that saw step-change increases in the V8's performance, and the latest engine programme is no different. Two new low-inertia turbochargers operate with far greater efficiency at lower engine speeds – they reach maximum turbine speed in half the time of the previous unit – thereby ensuring significantly reduced turbo lag and that prodigious wave of torque at any revs.

Furthermore, a reprofiled camshaft with an all-new roller tappet system provides revised valve timing and substantially improved refinement. These changes also deliver for increased power, enhanced durability and ensure compliance with European EÚ IV and ÚS LEV II standards. ( posted on conceptcarz.com) Although the 2007MY 6.75-litre engine produces around 300 horsepower more than its 1959 predecessor, its fuel consumption is only 60 percent of the original and thanks to its advanced fuel injection and exhaust controls, its emissions output is an incredible 99 percent lower than Bentley's first V8.

Drivetrain and Chassis
Such an impressive increase in power and torque is, however, of little benefit unless the powertrain is capable of delivering it to the driven wheels. For this reason Bentley's engineering team opted to introduce the latest six-speed ZF automatic transmission to the Arnage range. This state-of-the-art system offers two further ratios than the previous gearbox and has several key advantages over its predecessor:

- The wider range of ratios is specifically tuned to each Arnage model, ensuring greater flexibility, response and refinement for every model.

- Performance feel is also improved by using a sophisticated locking torque converter system which provides a more rapid response to throttle inputs.

- Three transmission modes (Drive, Sport and Semi-Automatic) allow the driver to take full advantage of the new gearbox. Semi-Automatic mode is accessed by placing the gearlever into the sequential manual gear-selector gate, where a new ratio can be engaged simply by pushing the lever forwards or backwards.

A sophisticated electronic management system plays a major role in providing fast yet smooth gearshifts regardless of how the car is being driven. Previously the Arnage's engine and transmission were governed by independent electronic systems; in the 2007 Model Year, an uprated Bosch computer-controlled management system ensures that both parts work as a single unit to produce a supremely refined yet highly responsive drivetrain.

'The new ZF gearbox gives us a different dimension in transmission control,' says Dr Úlrich Eichhorn, Member of the Board, Engineering. 'Our main objective was to get the engine and transmission working together enabling us to transmit every ounce of power. Úsing the lock-up in all gears eliminates what we call the ‘rubber-band' effect – the surge of engine speed without a corresponding acceleration of the car – and gives much more immediate connection of throttle input to road speed.

'As the engine speed approaches the point at which a gearshift is due, it signals to the transmission that it is time to shift, so the ratio changes are much quicker - it feels significantly faster from the driver's seat. Similarly, when the gearbox is ready to change up it asks the engine to reduce the torque just for the period of the shift, which adds to the refinement.'

Another important development for the 2007 Model Year Arnage range is the separation of the sports suspension and sports gearbox settings, allowing the driver to select their preference for each system independently – via a ‘Sport' button on the dashboard for the suspension and by positioning the gearlever for the transmission's Sport mode.

A comprehensive chassis tuning programme was instigated alongside the powertrain updates to ensure the Arnage's chassis comfortably handles the additional performance. Refinements to the ESP logic system allow more spirited handling without any reduction in stability or safety.

The Traction Control system is extensively recalibrated with the aim of avoiding unnecessary reduction in engine torque. The ESP system now monitors the car's overall stability rather than simply loss of grip to the wheels. This reduces the amount of intervention required and restores power earlier and more progressively, allowing the power of the engine to be fully exploited.

'We don't believe in creating power and then taking it away,' says Brian Gush, Director, Powertrain and Chassis. 'This new system allows the driver a lot more freedom to feel where the traction limit is without ever getting into trouble. The traction control is much more progressive and proportional – you can drift the car with some wheelspin but it never lets you get in any trouble. It is a calibration which keeps the spirited driver in mind.'

Source - Bentley