A 635d? Hmm, potentially an interesting combo…
Indeed. Mating the excellent twin-turbo 3.0-litre diesel to BMW’s mildly-facelifted 6-Series Coupe and Cabriolet, creating (they say) the world’s first diesel GT 2+2, is something we’ve been anticipating with intrigue. The 282bhp unit has the same power as an ‘80s M 635 CSi, yet the 427lb ft of torque is over 10 percent up on the current M6. Oh, and it’s delivered between 1750 rather than 6100rpm. And 95 percent is yours at 1500rpm, too. As such, BMW promises near-instantaneous throttle response from the sequential turbo set-up, aided by a quick-fire auto (no semi-auto nonsense here). It’s also the world’s first 40.9mpg luxo-sports car.
You’ve sold me on the figures but, as a petrolhead, I’m still to be convinced…
Try this. Cruise at 60mph, then tweak the throttle. Just a tweak, that’s all. Feel that? Instant response, linear as you like, with shove like no other 6 in normal use. With 62mph taking 6.3 seconds, this is a fast car – but all that torque means it’s real-world fast. It makes a mockery of all the flurried downchanges you need in an M6, and yet the other failing fast diesels can suffer – runaway, uncontrollable surge – is also metered. It’s like a very powerful petrol turbo (with similar response), and pretty additive to boot. Other than at tickover and near 4,000rpm, it doesn’t even sound dieselly: the straight-six vocals are throbby, bassy and very smooth.
So the ‘DIESEL’ inscription on the fuel gauge doesn’t spoil the big coop, then?
If anything, it enhances it. The 6 has always been about brawn rather than Porsche-style delicacy; revving the petrol six has thus generally felt slightly disingenuous (though, courtesy of direct injection, a power boost to 272bhp means there may be slightly less need to do so now). The somewhat aloof and twirly steering of our Sport test car accentuated this, as did a leaden ride. No, the 635d encourages a classic, accurately measured ‘fast out’ style – don’t worry about the ‘slow in’ bit, such is the grip from the massive 19”s, but revel in how you can lean on the rear with a bold throttle input and surge towards the horizon like someone’s lit a fuse.
What else have they done to the 6?
The launch of the diesel coincides with a mild facelift, but you’ll have to look hard. Headlights now have 5-Series-style LED running lights, there are new bumpers front and rear and the controversial bootlid has been recontoured. You still look at it and think Ssangyong Rodius, though. Inside, the equally controversial iDrive has another software update for simplicity and style’s sake, and there are detail changes to the centre console, but the most obvious change is that new gearlever. Standard to all 635d, the ‘Sports’ automatic comes with steering wheel paddles too, and offers speedy changes of a perceptiveness almost unheard of from a conventional six-speeder – and that’s in standard mode, never mind Sport (which also makes the throttle and Servotronic steering action, err, sportier). Other tech such as night vision, steering-shaking lane departure warning and active cruise control complete the updates.
It all sounds like diesel’s where it’s at…
BMW certainly thinks so. From the circa-2700 6-Series they sell each year in the UK, the 635d is quickly going to take around 60 percent of volumes; not bad, given that it’s starting from zero. That BMW is first to this sector and is already claiming such numbers suggests that others will have to soon follow. How appealing would a Jaguar XK with the 2.7 V6 or 3.6 V8 diesels be? Or a Mercedes SL 320 CDI? A 4.2 V8 TDI Audi R8 wouldn’t be without merit, either. Shame none are here, yet…
Verdict
Diesel gives the 6-Series the focus it’s needed, and is both a quicker and more satisfying car than the M6 in the real world, if you don’t fancy giving Senna-qualifying-at-Monaco commitment levels. It sounds nice and barely clatters either, while snappy throttle response and linear delivery puts paid to those diesel downers, too. All this and 600 miles per tank? Suddenly the 6-Series seems a one-car range to us. And once BMW starts fitting its EfficientDynamics technology to six cylinder cars it’ll be even better, too.