BMW 4 Series Coupe: Full details

We saw the sleek 4 Series Concept Coupe debut at the Detroit motor show in January, followed by a host of recent spy shots including the bahnstorming new twin-turbo six-cylinder M4 Coupe.

Now BMW has revealed the first images and full specifications of the 4 Series production model that will make its world premiere at the Frankfurt motor show in September, before replacing the 3 Series Coupe in Australia around October.

Like the 4 Series Convertible that will follow it early next year, the 4 Series Coupe – BMW’s direct rival for the Mercedes-Benz C-Class Coupe and Audi A5 Coupe -- is based on the all-new 3 Series sedan launched here last year.

Appearing faithful to the edgy concept in all respects except the less fussy lower bumper treatment, the production 4 Series rides on a 50mm-longer 2810mm wheelbase and is longer, wider, lower and 60 per cent stiffer than its predecessor.

At 4638mm long, 1825mm wide and 1362mm high, it is 26mm longer, 43mm wider and 16mm lower than the 3 Series Coupe, while front and rear wheel tracks are extended by 45mm and 81mm to a respective 1545mm and 1593mm.

That sees the 4 Series move closer to its larger rear-wheel drive 6 Series Coupe sibling in terms of overall dimensions, and further away from the 1 Series Coupe, which in turn will be replaced by the (potentially front-drive) 2 Series.

The 4 Series range is also expected to grow to include a four-door Gran Coupe derivative, mirroring the 6 Series family by 2015.
?While the 3 Series sedan is itself 10mm lower than the model it replaces, the 14mm-longer 4 Series sits a further 67mm lower, reducing its roll centre by 19mm over the 3 Series Coupe and giving it the lowest centre of gravity of any model in the BMW range.

Although its aerodynamic drag coefficient is a slippery 0.28Cd, the bigger new body is heavier than before, with the entry-level 420d weighing 30kg more than the previous 320d at 1450kg in six-speed manual form.

BMW says it has tailored the 4 Series’ springs, dampers, axle kinematics and elastokinematics and electro-mechanical power steering systems to suit the coupe’s more sporting nature compared to the 3 Series sedan, with which it shares the same basic interior layout.

However, apart from longer frameless doors, automatic seatbelt feeders, sportier seats and an optional 40/20/40-split rear seatback, the four-seat two-door adds a redesigned iDrive dial that is now a touch controller and debuts Driving Assistant Plus, which warns the driver of a potential pedestrian collision.

Options will include variable-ratio Sport steering and adaptive dampers, which will be standard on M Sport models.

The longer wheelbase liberates more rear legroom, but boot space increases by only five litres to 445 litres.

Australian specifications have not yet been announced, but in Europe the 4 Series Coupe will be available in five trim levels (including an M Sport variant with 19-inch alloy wheels to top the range, for now) and with six turbocharged engines matched to six-speed manual and eight-speed automatic transmissions with idle-stop.

Top of the pops until the M4 arrives is the 453i, powered by a 3.0-litre turbo-petrol six that delivers 225kW at 5800-6000rpm and 400Nm from 1200-5000rpm, while consuming 7.9L/100km (7.3L/100km auto).

That’s enough to propel the 1520kg 435i Coupe to 100km/h in 5.4 seconds, although Australians will not have access to a new xDrive all-wheel drive version that reduces that to 4.9 seconds, making it almost as quick as the outgoing M3 V8 coupe.

At the other end of the line-up, the 1450kg 420d Coupe employs a 2.0-litre turbo-diesel four-cylinder producing 135kW at 4000rpm and 380Nm of torque (1750-2750rpm), consuming 4.7L/100km and hitting 100km/h in 7.5 seconds.

The mid-range 428i Coupe gets a 2.0-litre turbo-petrol four with 180kW at 5000-6000rpm and 350Nm between 1250-4800rpm. It sprints to 100km/h in 5.9 seconds and consumes as little as 6.3L/100km, making it quicker and more efficient than the 328i sedan.