What is it?
This is the most powerful version yet of BMW’s latest 3 Series. With all of its seventh-generation siblings running four-cylinder powerplants, the M340i is also the only new petrol 3 Series to have a six-cylinder engine.
The luxuriously equipped M340i xDrive has been conceived and developed in close co-operation with BMW’s M division, hence the M in its name. It fills the gap in the German car maker’s line-up between the excellent 330i and the upcoming new M3, due in 2020.
Power is delivered by the latest iteration of BMW’s B58 engine. The 3.0-litre unit receives a new two-scroll turbocharger and particulate filter among other detailed changes. Power is up by 48bhp on the earlier 340i – the model it indirectly replaces - at 369bhp and torque rises to 369lb ft between 1850rpm and 5000rpm.
By comparison, the existing 330i’s turbocharged 2.0-litre four-cylinder engine delivers 255bhp and 295lb ft.
Deploying the engine’s reserves is an eight-speed torque-converter automatic gearbox, which features its own unique ratios and an integral launch control function, and BMW’s latest xDrive four-wheel drive system complete with an electronic differential lock on the rear axle.