New six-pot for spicy BMWs

BMW will usher in a more powerful six-cylinder turbocharged petrol engine as well as new names for its warmed-over M135i and M235i models later this year.

The German car-maker will drop the M135i and M235i moniker and adopt the M140i and M240i badges, following a similar name change that was introduced last year for the 3 Series (335i became 340i).

Apart from the variant name, the big change is under the bonnet, with the introduction of a new in-line six cylinder 3.0-litre unit developing 250kW at 5500rpm and 500Nm from 1500-4500rpm, representing a 10kW/50Nm increase over the outgoing versions.

The new engines will start rolling off the production lines in Europe in July and Australian deliveries are likely to kick off in the fourth quarter of the year. The variants on offer Down Under include the M140i five-door hatch (the three-door is not available here), the M240i Coupe and Convertible.

The M140i and M240i – part of BMW's M Performance stable – feature further developed TwinPower Turbo technology and use an eight-speed Steptronic Sport dual-clutch automatic transmission, although manual fans can order a six-speed gearbox as a no-cost option.

BMW says it has improved the gearbox, which now features a throttle blipping function on down-shifts, while the auto has also been enhanced for greater fuel efficiency.

Performance and fuel economy gets a lift from the new donk, with the M140i completing the 0-100km/h dash in 4.6 seconds when matched with the auto, a 0.3s improvement over the M135i hatch. The manual is 0.2s slower.

The M240i Coupe's 0-100km/h has dropped by 0.4s to 4.6s for the auto (4.8s for the manual), while the drop-top is 0.3s quicker at 4.7s (4.9 in manual guise).

The all-wheel drive xDrive versions are even quicker but they are not available in Australia which only gets the rear-drive models.

Fuel use has also improved, with auto versions of the M140i down from 7.5 litres per 100km to 7.1L/100km (7.8L down from 8.0L in the manual), while the M240i is also down from 7.6L to 7.1L for the auto Coupe (7.8L for the manual) and the Convertible has dropped from 7.9L to 7.8L (8.3L for the manual).

Carbon dioxide emissions have improved from 175g/km in auto variants to 163g/km, and from 188g/km to 179g/km for the manual.

BMW says the new engine features an aluminium crankcase and cylinder head, and that refinement has been further improved by the use of new near-source acoustic shielding. Electric wastegate control and the close-coupled arrangement of the catalytic converter help to lower emissions, according to the car-maker.

Responsiveness and efficiency is improved thanks to the latest version of the Valvetronic fully variable valve control and the M Performance models also get Double-Vanos variable camshaft timing on both the intake and exhaust sides.

Already standard and carrying over are idle-stop, a map-controlled oil pump, Electric Power Steering and Brake Energy Regeneration.

Australian specification and pricing will be revealed closer to the models' arrival in Australia, but some standard gear includes 10mm-lowered M Sport suspension, 18-inch M light-alloy wheels, an M Sport braking system, Variable Sports Steering with Servotronic function, a model-specific M aerodynamic package and exterior mirror caps in Ferric Grey metallic.

The cabin features cloth and Alcantara sports seats with blue contrast stitching, an M leather steering wheel and an M driver’s footrest.