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6 Series Cabrio - E64 (2004 - 2007) - Lightweight and Drivetrain

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6 Series Cabrio - E64 (2004 - 2007)
Lightweight and Drivetrain
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Intelligent Lightweight Technology
Low weight affords greater dynamism, improved safety, enhanced environmental compatibility and increased comfort.
But keeping weight low on a convertible is a more exacting task than on a closed car where a fixed roof contributes significantly to torsional body stiffness.
To overcome this, the 6 Series Convertible redefines lightweight engineering philosophy.

First, conventional materials are replaced by lighter materials wherever possible.
Second, wherever feasible, less material is used.
Finally, despite using less material, components either retain or have increased strength by intelligent reinforcement.

An example of this technology can be found in the 6 Series Convertible's body, which features a unique aluminium front end that is significantly lighter than a conventional front end constructed from steel.
This makes a valuable contribution to the car's near perfect 50:50 front/rear weight distribution.

Additionally, the housings supporting the front struts are in pressure-cast aluminium alloy, while the doors, rollover safety system, the inner and outer skins of the bonnet, the brake disc callipers and carriers plus most suspension and axle parts are also made of aluminium.
Further weight saving comes from the front wings which are made from thermoplastic and the boot and roof compartment lids which are formed from SMC (sheet moulding compound).
As a result, BMW becomes the first manufacturer in volume production to have a 'hybrid' bodyshell of four different materials.

To ensure that this comprehensive toning and weight watching doesn't go to waste, the 6 Series Convertible shares the 6 Coupé's bespoke, all-aluminium platform chassis.
This displays another key advantage to designing the car alongside its Coupé cousin from scratch and results in the new Convertible leading the field of open-top 2+2s in terms of torsional stiffness and vibration comfort.

This fastidious and individual engineering approach bestows the 6 Series Convertible with impressively low weight for this class of car at 1,890kgs, (or just 1,815kgs without the driver (68kgs) and luggage (7kgs) weights required by EU legislation in official communications).
This helps ensure excellent driving dynamics and exhilarating performance, while delivering no compromise on luxurious accommodation, everyday practicality or impeccable safety.

BMW's ultra-refined 4.4-litre V8 petrol engine - equipped with VALVETRONIC valve lift control, DIVA variable intake manifold length control and bi-VANOS valve timing control - was 2002's International Engine of the Year.
It provides the new 645Ci with instant thrust, flexible performance and substantial reserves of power.
In addition, efficiency is improved by the new variable intake ducts located just behind the BMW kidney grille.
Six moving 'wings' automatically control the channelling of cooling air to the engine, improving aerodynamics when closed and enabling faster engine warm up from cold.

Delivering up to 333bhp (245kW) at 6,100rpm with maximum torque of 332lbs-ft (450Nm) at a relaxed 3,600rpm, the manual (or SMG-equipped) 6 Series Convertible can accelerate from 0-62mph in 6.1 seconds (the automatic version taking a mere tenth of a second longer), carrying briskly on to an electronically limited 155mph.
The exhaust note, hardly audible at idle, quickly builds to a beefy, yet unobtrusive, rumble.
At the same time fuel consumption on the EU combined cycle is rated at an impressive 24.6mpg for the automatic and 22.1mpg for the manual.

The 645Ci customer has a choice of three six-speed transmissions: a conventional manual, an automatic with STEPTRONIC manual selection, or the sequential paddle-shift, clutchless SMG system.
Power in all cases is directed to standard fit 18 inch alloys (19 inch optional) rolling on Run-flat tyres with a tyre puncture warning system.

Last Updated on Monday, 12 April 2010 14:40  
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