BMW 3-series – engine and gearbox
Four-cylinder petrol is a little dull, but 3-litre six-cylinder models are excellent. All-wheel drive is an option with all but the 320i and 320d, with a manual no longer available
In 2024, there are effectively four engines available for the BMW 3-series: the 2-litre B48 four-cylinder petrol, 2-litre four-cylinder diesel, 3-litre inline six-cylinder diesel and range-topping 3-litre inline six-cylinder petrol for the M340i. The 2-litre four-cylinder petrol is available in both pure-combustion and plug-in hybrid forms in the 320i and 330e.
At the bottom of the range is the 2-litre B48-powered 320i with 181bhp and 221lb ft of torque, and while it's far from fast, it still manages a respectable 7.4sec 0-62mph time. The entry-level diesel 320d produces similar power at 187bhp, but an additional 74lb ft of torque helps it cover the 0-62mph sprint in a lower 6.9sec. All models now come with an 8-speed automatic as standard.
Move up the range to the plug-in hybrid 330e (utilising the same B48 2-litre four-cylinder as the 320i) and power stands at a more potent 288bhp and 310lb ft of torque, making for a 5.8sec 0-62mph in both rear-drive and all-wheel drive forms. Switch to pure electric drive and a 108bhp, 195lb ft output isn't quite as impressive, but is still more than adequate for city driving.
While there’s nothing desperately wrong with this four-cylinder turbo unit it’s not particularly inspiring either. Power and torque delivery is fine and there’s very little lag to speak of, but aurally it’s pretty disappointing and when this is added to the 3-series’ overall improvement in terms of refinement the overall picture is slightly less sporting in feel than it was before.
The M340i xDrive is the only petrol-engined 3-series with a six-cylinder inline engine, and it doesn't disappoint. Available only with xDrive all-wheel drive, it converts its 369bhp, 369lb ft output to pace remarkably well, achieving a quoted 4.4sec 0-62mph time and 155mph top speed (some independent tests have found the former to be quite conservative, however). Power delivery is relentless when pushing on, but low speed, everyday driving is a comfortable affair, with effortless torque and a silky ZF automatic transmission.
The 3-litre six-cylinder M340d xDrive is the most powerful diesel model of the range, and while its 335bhp output is lower than that of the M340i, a monster 516lb ft torque figure makes it feel just as potent in some scenarios – 0-62mph comes in a quoted 4.6sec.
