BMW has previewed its all-new 4 Series Gran Coupe, which will be the feature car on its Geneva motor show stand in early March.
The four-door liftback will flesh out the 4 Series range to three models after the 4 Series Coupe and upcoming 4 Series Convertible, and will be BMW’s second design-driven ‘Gran Coupe’ luxury car behind the 6 Series Gran Coupe launched in 2012.
Strangely, the 4 Series Gran Coupe shares precisely the same footprint as the elegantly formed 4 Series Coupe, right down to its external length, width and height dimensions.
It shares the same 2810mm wheelbase as the two-door coupe, too, and looks set to take on the ageing A5 Sportback as it duplicates Audi’s strategy of squeezing an entirely new range in the tiny gap between its existing, traditional models.
While Mercedes-Benz is yet to offer a competitor, a swoopier new mid-size model family positioned just above this year’s all-new C-Class is only a couple of years away.
But although the newest Gran Coupe shares much with the 4 Series Coupe, it will not go down the high-performance path. BMW has ruled out an M4 Gran Coupe, even though it has an M6 Gran Coupe, but the 4 Series Gran Coupe will become available with mid-step M Performance Automobiles upgrades in late 2015 or early 2016.
The arrival of the 4 Series Gran Coupe goes some way to explaining BMW’s rationale for the relatively conservative body design of the current 3 Series, because it always knew it had a more extroverted design package in the pipeline to combat the leaking of style-conscious customers.
A pet project of BMW design boss, Adrian von Hooydonk, the 4 Series Gran Coupe differs from the 6 Series Gran Coupe philosophy mainly by delivering a long, liftback to access the luggage area, rather than a conventional boot lid.
Given its heft, it’s fortunate that the liftback will be operated by a button on the car’s key fob, a button in the cabin or a foot-swipe sensor below the rear bumper.
It won’t be the last word in mid-size style-driven BMWs, however, because a production version of the X4 SUV, shown as a concept car at the LA motor show in November 2013, will hit European streets in April before arriving Down Under later this year.
While it was conceived to be a more stylish alternative for traditional 3 Series buyers, the 4 Series Gran Coupe is longer and wider than the BMW mainstay sedan, but the drive for design has given it a lower roofline.
Even though it’s 14mm longer and wider than the 328i, the roof is 40mm lower at its highest point above the driver’s head, though it’s slightly higher in the xDrive all-wheel drive variants.
For all that, its 4638mm length, 2810mm wheelbase, 1545mm front track and stabilsing 1594mm rear track are identical to the Coupe’s, so BMW designers and engineers have effectively had to squeeze two extra short, frameless rear doors into the bodywork and shorten the Coupe’s elongated front doors to help them fit.
It doesn’t just share the coupe’s dimensions, either, because the nose is identical, with the same lights, grille, air intakes and bonnet. You have to slide back to the roof to find a different dimension, because the Gran Coupe’s roofline is 12mm higher and 112mm longer before it sinks into the liftback glasshouse and the rear quarter panels.
The Gran Coupe adds 35 litres to the Coupe’s luggage area to take it out to 480 litres, though that can be bumped out to 1300 litres by folding the 40/20/40-split rear seat flat.
Besides sharing identical suspension architecture, with a multi-link rear suspension and a sophisticated strut front-end -- both tuned for the car’s extra weight -- it also rides on 17-inch alloy wheels throughout the line-up, with the exception of the 418d version on 16-inch rims.
It’s lighter than it looks, though, with the addition of two doors, more roof metal and a liftback adding only 50kg to the equivalent Coupe, so the base 420i Gran Coupe weighs a surprisingly light 1480kg. That’s about 80kg heavier than the standard 320i sedan.
The 4GC will land in Europe with the same dizzying array of powertrains as the Coupe, including five EU6-spec engines for four model designations and a choice of six-speed manual or, more commonly, eight-speed automatic transmissions. BMW expects another two diesel variants to be stuffed into the Gran Coupe late this year as well.
The biggest hitter of the line-up will be the 435i Gran Coupe, with an identical 225kW version of the 3.0-litre turbocharged in-line six-cylinder engine. The 400Nm engine lifts the 435i Gran Coupe to 100km/h in 5.2 seconds if it has the optional eight-speed auto (likely to be standard in Australia) and the same gearbox lends itself to delivering 7.1L/100km on the NEDC cycle and 189g/km of CO2.
The real sweet spot of the 3 Series range is usually accredited to the 328i and BMW expects the 428i to fill the same role in its Gran Coupe form. The 2.0-litre four-cylinder motor uses twin-scroll turbocharging, direct fuel-injection and variable valve timing to pump out 180kW and 350Nm of torque, and is capable of hitting 100km/h in six seconds (again, with the auto attached to the rear of the engine).
Both the six and the best of the fours are strong across the board, with the 435i’s torque peak arriving at only 1200rpm and remaining in a flat line to 5000rpm, while the 428i’s torque peak hits only 50rpm later and begins to taper off 200 revs sooner.
It makes up for it by giving a bigger flat top to its power curve, which hits at 5000rpm and remains at its 180kW heights until 6500rpm, where the six-pot’s power plateaus for only 600rpm from 5800rpm.
It also has an economy advantage, posting a combined figure of 6.2L/100km and CO2 emissions of 154g/km, partly due to weighing 65kg less at 1530kg, even with the 20kg handicap of the automatic transmission.
A less-stressed variant of the 328i engine drives the 420i Gran Coupe, though it’s unlikely to come to Australia, and it’s backed up by three different diesels.
The common-rail 2.0-litre four-cylinder turbo-diesel powers both the 418d and the 420d versions of the Gran Coupe, with 105kW and 130kW respectively or, for the torque lovers, 320Nm and 380Nm respectively.
They’re also the most economical, at 4.5L/100km and 4.6L/100km respectively, with the difference between them neatly explained by the aero advantages of the slower model’s narrower 16-inch tyres.
The diesel family will get stronger, with a 430d and a 435d xDrive both in the pipeline. Both engines use the same 3.0-litre turbo-diesel architecture. The 435d will be a thumper, with 230kW and 630Nm, which BMW insists requires all-wheel drive to manage.
The 430d at least comes as a rear-driver, with 190kW and 560Nm of torque, though this too can be ordered as an all-wheel drive if you prefer. At least, it can in Europe.
Read the latest news and reviews on your mobile, iPhone or PDA at carsales' mobile site...
Don't forget to register to comment on this article.