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.
Underpinning the M340i xDrive is specially tuned M Sport suspension. It features a nominal 10mm reduction in ride height compared with other 3 Series models. A full gambit of elastokinematic changes is also included to provide the new BMW model with what is described as “sporty and authoritive” handling.
Adaptive damping control, as fitted to our test car, is available as an option. It provide four levels of damping stiffness via Eco Pro, Comfort, Sport and Sport Plus modes.