World’s most powerful production six-cylinder diesel introduced to BMW 6 Series
from Automotive (1568 articles)
New BMW 635d
Image Gallery ( 19 images )July 2, 2007 BMW has for the first time combined its twin-turbocharged, six-cylinder diesel with the marque’s flagship Grand Tourer in the form of the new 635d. Coinciding with the revamp of 6 Series model line-up to include Active Headrests, Brake Energy Regeneration and other fuel saving and emissions-cutting technology, the 635d Coupé and Convertible will hit showrooms in the UK in October with world’s most powerful production diesel under the bonnet.
The BMW 635d Coupé records a zero to 62mph time of 6.3 seconds while the Convertible achieves this in 6.6 seconds. Both have top speeds electronically-limited to 155mph but still maintain impressive fuel efficiency levels - the Coupé still achieves 40.9mpg on the combined cycle and a CO2 emissions figure of 183g/km, while the Convertible retains near identical figures recording 39.2mpg and 190g/km.
The new 635d has also been given a subtle restyling to mark the technological changes including a revised headlight arrangement featuring LED technology and clear lenses, a new style of front valance and repositioned vertical struts on the front spoiler to accommodate a different shape of air intake for the car.
Powered by a twin-turbocharged 2,993cc engine with an all aluminium crankcase and third generation common rail fuel injection system, the 635d comes with an output of 286hp and 580Nm of torque. These performance figures have been made possible by the unique way the twin turbochargers work. A smaller turbocharger provides near instantaneous response for swift initial acceleration before a larger turbocharger comes in mid-range to provide additional thrust through to the redline. Peak torque is available from just 1,750rpm to deliver a seamless wave of smooth acceleration.
EfficientDynamics
The performance is made possible by the introduction of “EfficientDynamics” technology that introduces Brake Energy Regeneration and the implementation of various needs-only operations of ancillary units for the first time in the 6 Series range. This includes the ability to decouple the air-conditioning compressor from the drive-train to prevent unnecessary drag on the engine and the use of lower viscosity fluids in key components to reduce friction. An optimum gearshift indicator is fitted to advise on economical motoring, while active flaps located behind the kidney grille can close off to improve aerodynamic flow and reduce drag. These measures mean lower fuel consumption and emissions figures than would previously have been possible.
Revised petrol powerplants
The BMW 635d is joined in the range by the 630i and 650i, offered in both Coupé and Convertible bodystyles. The six-cylinder magnesium and aluminium engine in the 272hp 630i now features new lean burn technology in the guise of high precision direct injection and double-VANOS variable valve technology. With its piezo crystal injectors for optimium fuel atomisation, the new style of induction makes for a near-complete fuel vapour burn and improves engine efficiency.
The new 630i Coupé records a 4.4mpg improvement (now 35.8mpg in combined fuel consumption) compared to the previous model and CO2 emissions also drop from 216g/km to 188g/km. BMW 630i Coupés fitted with automatic transmissions post even better performance figures with combined fuel consumption rising from 29.7mpg to 36.7mpg and emissions falling from 238g/km to 184g/km. The 630i Convertible achieves a combined fuel consumption figure of 34.0mpg compared to 29.4mpg, while CO2 emissions drops from 229g/km to 198g/km.
