BMW 640d Coupe review (2011 onwards)

What - BMW 640d Coupé M Sport
Where - North Wales
Date - October 2011
Price - £66,745
Available - Now
Key rivals -Mercedes SL, Jaguar XK, Maserati GranTurismo

Summary - Exceptional diesel engine turns the 6 Series into a sophisticated musclecar that has significant sector-unique appeal. It's still not the most sporting of cars but is nevertheless now very well-rounded.

We like - Staggering engine has power, economy and even aural appeal, attractive new M Sport styling kit, overall GT car ability
We don't like - Not as sporting as some BMW, driver is a touch removed from the action, it isn't cheap

First impressions

BMW is alone in offering a diesel-engined four-seat luxury coupé. However, as over nine in 10 sales of the outgoing 6 Series sported a turbodiesel, it is clearly onto something. Similar sales dominance is thus expected of this all-new second-generation model.

This car was launched earlier in 2011, first as a convertible and later as a coupé. It didn't really enthuse us in 640i and 650i guise, proving a bit too bland and characterless against the impressive Jaguar XK, dominant Mercedes SL and flawed yet charismatic Maserati GranTurismo. The diesel is thus a key test for 6 Series appeal in the UK.

BMW has also introduced M Sport trim to the 6 Series for the first time. The old model only offered 'Sport': this goes further with M GmbH-developed aero enhancements and wheels to create a more sporting and aggressive look, particularly from the front. This certainly answers earlier complaints that it looked too bland: the muscular new 6 M Sport is very eye-catching.

It's expected to be popular too: nine in 10 UK cars will be M Sport. As nine in 10 will also be diesel (despite costing £2,500 more than the 640i), and two-thirds will be coupé derivatives, it's clear to see the car we drove for the first time in North Wales is the most important new 6 Series for BMW to get right. Has it?

Performance

This diesel engine is pretty much as fast and as powerful as the comparable 640i petrol engine (0-60mph in 5.5 seconds is remarkable) but massively more torquey. It has a mighty 464lb/ft of pulling power from just 1,500rpm - little more than tickover - which gives you an idea of how it feels on the road.

It is, in short, very, very strong. This engine has a real muscle car feel, with swelling shove available whenever you brush the accelerator pedal. You don't have to rev it hard or even wait for it to come on stream: minimal turbo lag (from sequential turbos - one small, one large) means it's there almost instantly.

Remarkably, this is also a diesel engine that loves to rev. Peak power is a relatively high 4,400rpm and the vim with which it spins round to the redline is amazing: no vibration, no clatter, no gravelly sound effects. If anything, it sounds almost like a Porsche flat six petrol at higher revs...

The eight-speed automatic transmission is the perfect companion. It's always in the right gear to best exploit the diesel engine's narrow rev range, proving more intuitive than even manual control by the driver via steering wheel paddles would. It comes with standard stop-start too, disguising the merest hint of engine vibration at idle.

Ride and handling

The 6 Series is more luxury GT than outright sports car. Yes, it is a BMW, but it is not a 1 Series M Coupé in drag: luxury coupé buyers seek less raw intensity and more plush-riding comfort from their cars, which the 6 Series provides.

It is inherently well balanced which, with the huge muscle of the turbodiesel, gives a satisfyingly coherent mechanical feel on the road. It seems composed and well judged which gives a pleasing and surefooted sense of confidence in all driving situations - yes, even when playing with power-oversteer out of tight bends...

Apart from the 19-inch wheels, M Sport models don't actually have any suspension changes. The test car came with BMW's optional Adaptive Drive system, which has electronic dampers and an active anti-roll system. This defaults to Comfort mode, which is a bit too soft and disjointed: the sharp chassis reacts more quickly to steering inputs than the body, which feels odd.

Sport is far better, making the 6 Series incisive and easy to flow down twisty roads despite its ample size. It's not particularly involving and loses its sporting pretensions when you really press on, but as an easygoing GT steer, it's more than able. Sport doesn't ruin the ride either, although it is a bit pattery even in Comfort mode.

Interior

BMW has returned to its roots and given the 6 Series a decidedly driver-focused cabin. It is asymmetric and wraps around the driver for a cocooned and sporting feel. Perhaps BMW's best current interior, the design is also interesting and characterful.

Build quality is excellent and there is a very reassuring feel when the door is slammed. Occupants sit low, on firm, multi-adjustible seats, helping give a purposeful feel behind the wheel. The BMW feels long, wide and purposeful: just how a good GT should feel.

Although BMW calls it a 2+2, don't expect to win much praise from adults sat in the rear. It is pretty cramped back there, with getting in and out also proving cumbersome. The boot, however, does take a trio of the obligatory golf clubs.

We love the wide iDrive display screen on the top of the dash, through which the car's multitude of systems are controlled. It is possible, with options, to create a very complicated 6 Series indeed, but iDrive does at least make it easy to navigate around the mass of configurations.

Economy and safety

Fuel economy is staggering. Not only is the 640d exceptionally rapid, it is also exceptionally fuel efficient. It averages 51.4mpg, a full 15.2mpg (yes, 15.2mpg) more than the 640i which this engine outperforms on the road. CO2 emissions of just 145g/km are also 36g/km lower than the petrol alternative.

BMW offers a brace of new safety technology features on the 6 Series, including night vision with pedestrian detection, parking assist, surround view, speed limit display and a lane departure warning system. The enhanced head-up display also remains unique in this sector.

The MSN Cars verdict

Is it any wonder more than nine in 10 6 Series are diesel powered? The new 640d moves the diesel GT game on again with a real powerhouse of an engine that's as cultured as it is powerful and efficient. M Sport trim enhances the elegant looks of the 6 Series too and, while it's not the most sporting to drive, in its optimum diesel guise it proves to be the consummate GT car.

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