Set for an LA show debut next month is the BMW 4 Series Convertible. The vehicle gets a three-piece folding hard top that opens in 20 seconds at speeds of up to 18 km/h. Additionally, the roof’s headlining cuts noise by up to 2 dB over the E93 3 Series Convertible.

With the roof up, the drag coefficient is 0.28 and there’s 370 litres of boot space (a 20-litre improvement). The numbers are 0.33 and 220 litres respectively in open-top mode. The folded roof is pivoted upwards in the boot by an electro-hydraulic loading assistance system to allow more storage space and easy access.

Three-temperature driver and front passenger neck warmers are optionally available for the first time (both on the standard seats as well as optional sports seats with recessed headrests) – when the top is down, the temperature is automatically controlled in relation to the outdoor temperature and vehicle speed. Also optional is a redesigned windblock that can be stored behind the back seat.

Measuring 4,638 mm long, 1,825 mm wide and 1,384 mm tall, with a 2,810 mm wheelbase, the BMW 4 Series Convertible’s roll-over bars that, in critical situations, spring out from behind the rear seats in under 200 milliseconds.

The usual EfficientDynamics (regenerative braking, Eco Pro mode, coasting etc) and Connected Drive (head-up display, Driving Assistant Plus, LED High Beam Assistant etc) suite of systems and aids carry over from the coupe. Standard wheels are 225/50 R17s; 18s or 19s are optional.

Three variants are available at point of launch: 420d, 428i (with optional xDrive) and 435i. Like its fixed-roof sister, Sport, Modern, Luxury and M Sport trims are offered, and transmission is taken care of by either a standard six-speed manual or optional eight-speed Sports auto, with start/stop standard on both.

Available for Europe, the 420d Convertible draws 184 hp at 4,000 rpm and 380 Nm of torque between 1,750 and 2,750 rpm from a 2.0 litre four-cylinder turbodiesel. The century sprint is dealt with in 8.2 seconds and top speed is 235 km/h. Average fuel consumption is quoted at 5.1-5.3 litres per 100 km and CO2 emissions at 133-138 grams per km.

The 428i Convertible’s turbocharged 2.0 litre four-cylinder petrol uses its 245 hp between 5,000 and 6,500 rpm and 350 Nm of torque to catapult it to 100 km/h from rest in 6.4 seconds and onwards to a limited 250 km/h. It’s capable of returning 6.8-7.0 litres per 100 km and emitting 159-163 grams of CO2 per km (6.6-6.7 and 154-157 if fitted with eight-speed Sports auto).

Finally, the 435i Convertible’s specs are as follows: turbocharged 3.0 litre straight-six petrol, 306 hp between 5,800 and 6,000 rpm and 400 Nm from 1,200 to 5,000 rpm, 0-100 km/h in 5.6 seconds, 250 km/h limited, 8.1-8.4 litres per 100 km and 190-195 grams of CO2 per km (7.5-7.7 and 176-180 if fitted with eight-speed Sports auto).