NEW YORK MOTOR SHOW: BMW M4 Convertible

BMW’s cracking new M3 sedan and M4 coupe appeared at the Detroit motor show in January and will go on sale here in July, powered by a 317kW/550Nm twin-turbo straight six.

Now the same feisty new BMW M division engine has been fitted to the 4 Series Convertible, which arrived in Australia last month, offering similar thrills in an open-top body.

The M4 Convertible will make its world debut at the New York motor show on April 16, alongside global premieres of the all-new X4 and 4 Series Gran Coupe -- both of which arrive here in June – and, following their Geneva show reveals last month, the facelifted X3 and plug-in hybrid X5, which are also due here this year.

Expect the M4 Convertible, which we spied during testing in January, to arrive here by October, priced slightly than the M3 Convertible it replaces.

It will also be quicker than the M3 drop-top, thanks in part to a 60kg weight reduction to 1750kg in standard six-speed manual guise. This is thanks partly to the use of aluminium in its chassis and for the bonnet and front quarter panels, as well as a carbon-fibre reinforced drive shaft and engine bay strut.

Officially, the M4 Convertible sprints to 100km/h in 4.6 seconds in manual form – 0.6 sec faster than the M3 cabrio and 0.3 sec sooner than Audi’s 1920kg RS5 Cabriolet.

That drops to just 4.4 seconds with the optional seven-speed M Double Clutch Transmission and the topless M4 is also more efficient than before, consuming fuel at the rate of between 8.7 and 9.1L/100km.

But because it’s significantly heavier than both the M3 sedan (1520kg) and M4 coupe (1497kg), it’s also three-tenths slower to 100km/h than both models, which hit the national highway limit in a claimed 4.1 seconds.

Of course, the M4 Convertible’s mechanical package has already been previewed via the 4 Series Convertible and the M3/M4 twins.

Like the two-doors on which it’s based, it offers just four seats, but rides on the same 2812mm wheelbase and 4671mm overall length as the 3 and 4 Series models.

Its three-piece folding metal roof opens in the same 20 seconds (at speeds of up to 18km/h) as the 4 Series Convertible.