BMW 3 Series saloon - Engines, drive & performance
Agile, comfortable and quick, only its lifeless steering spoils the 3 Series as a driver's car
The latest BMW 3 Series sticks to the time-honoured layout of front engine and rear-wheel drive, which has underpinned the model since the early 1970s. However, progress has brought subtle changes over the years, and each incremental change has mounted up to make today's car thoroughly state-of-the-art.
As ever, the 3 Series is available with BMW’s xDrive four-wheel drive transmission – for drivers who want more traction in slippery conditions.
A clever suspension design is also among the list of improvements made to the 3 Series for the seventh-generation. Described as ‘stroke dependant’, it provides softer damping when the car is lightly loaded, becoming firmer as the car's weight increases. It’s certainly an effective set-up, and even on poorly maintained UK roads the suspension certainly maintains a supple ride without upsetting the BMW's composure in corners.
Better still, this new found comfort isn’t at the expense of the BMW’s sporting nature. Although we've not tried the entry-level SE trim, the Sport and M Sport cars we've driven delivered a great class-leading balance between comfort and cornering prowess.
Although the ride is firm on the worst British roads, the 3 Series is far from uncomfortable. The bumps of our test route were rounded off nicely, leaving passengers exposed only to mild jolts, rather than the severe shocks that once plagued sporty saloons. Road surface imperfections tend to be betrayed in a little more detail, though, when the larger 18-inch alloy wheels are fitted – you get a sense of bumps and ripples in the road surface more easily. Buyers wanting greater comfort should consider the optional adaptive dampers, which can be adjusted to soften or stiffen the ride to taste. The only downside is that this system is now only available as part of the expensive M Sport Plus Pack.
The upshot of the bigger wheels and wider tyres is an even more grippy, responsive car. With the rear wheels further apart than the front (a measurement known as a car's 'track'), the 3 Series feels very assured and stable, which leads to a real sense of confidence when you head into a corner. The only thing that detracts from the BMW as a genuinely rewarding car is the steering, which has the slightly remote, uninvolving feel from which fuel-efficient electric power steering systems often suffer.
Honed by BMW's M division, the BMW M340i xDrive is the hottest version of the 3 Series in the regular range, sitting beneath the BMW M3. In this niche of mid-level performance saloons it goes head-to-head with the Mercedes-AMG C 43 and the diesel-powered Audi S4, offering enthusiasts a great chassis and rapid acceleration. It arguably doesn't feel quite as special as its Mercedes rival, but there's no denying its ability to cover ground at an astonishing pace.
BMW 3 Series diesel engines
The 318d is the entry point into diesel 3 Series ownership and boasts mild-hybrid engine assistance when specced with BMW’s eight speed automatic gearbox. This consists of a 48-volt starter generator and a small battery that’s charged using the energy normally lost under coasting and braking. It also provides an overboost of up to 11bhp under full throttle to aid acceleration, resulting in a 0-62mph time of 8.2 seconds. Go for the manual version without the mild-hybrid tech, and 0-62mph takes 8.4 seconds.
The 320d badge is a familiar one because it’s on the rear of so many 3 Series models sold. For 2020, the rear-wheel-drive model also gets the same mild-hybrid assistance used in the 318d. With a 187bhp power output and low running costs, it seems likely to remain a popular choice among buyers of the latest generation 3 Series.
In true diesel style, its performance is better described as effortless than exhilarating, but 0-62mph in 6.8 seconds is pretty quick, and a 149mph top speed ensures relaxed high speed cruising. Thanks to its twin turbochargers, it very rarely feels out of breath either. It proves quiet when a constant speed is maintained, and – while it gets a little loud at full throttle – it's less noisy generally than the previous model.
The eight-speed automatic gearbox changes through the gears almost imperceptibly, and manual gear changes are just as prompt and smooth when you take manual control via the steering wheel paddles. However, the gearbox is so well calibrated that you might as well just leave it in full automatic mode and save yourself the effort.
The 330d takes just 5.3 seconds to hit 62mph, and is even quicker when equipped with the xDrive system, while the M340d deserves its place on our list of the fastest diesel cars with its 0-62mph time of 4.6 seconds.
The petrol 318i model is now the cheapest 3 Series you can buy, with prices for SE spec cars starting at around £33,000. With 154bhp, it also has the lowest power output of the range. Despite its lowly billing, the entry-level model is pretty capable, with 0-62mph taking only 8.4 seconds.
Go for the rear-wheel-drive 320i, and power increases to 181bhp and 0-62mph is completed in a reasonably swift 7.1 seconds. It’s also good to drive, with poised and well-balanced handling that’s reminiscent of the BMWs of yesteryear, with a slick eight-speed automatic gearbox making it a strong all-rounder.
We expect the 320i will be plenty for many petrol fans, although there are a couple of faster-still versions. It’s worth noting that all petrol cars come with the automatic gearbox as standard - the six-speed manual is only offered on 318d and 320d diesel variants.
The 330i petrol, which is the third of four petrol engine choices currently available, is a 2.0-litre, four-cylinder engine and not the 3.0-litre six-cylinder engine you might expect if you’re familiar with the way BMW has historically badged its cars.
That fact might disappoint some BMW fans but they need not fear any lack of power. In fact, the 330i produces 254bhp, which is a figure once reserved for much bigger, thirstier engines. BMW claims it's enough for 0-62mph in just 5.8 seconds, allied to a 155mph top speed. And, while it can't match the silky feel of a six-cylinder engine, it makes a pleasant noise and revs enthusiastically towards its 5,000rpm power peak.
The new BMW M3 is the height of 3 Series performance, with 503bhp and a sub-four second 0-62mph time making it one of the fastest saloons you can buy. It does have divisive looks and an eye-watering £75,000 price tag, so many buyers will be drawn to the M340i instead. It’s almost as quick but close to £25,000 less expensive. We found its 369bhp, 3.0-litre turbocharged engine to have more than enough power to satisfy all but the most demanding of enthusiasts – 0-62mph takes just 4.4 seconds, thanks in part to the standard M Performance four-wheel drive system. That’s quicker than the last generation of BMW M4.
In essence, the example we tested felt like a shrunken BMW M5 super saloon. The four-wheel drive system is unobtrusive, so the M340i feels more like a very obedient rear-wheel drive car most of the time. It makes the right noises, though, with characteristic pops and bangs from the exhaust when you lift off the accelerator.
Alas, the prototype M340i that we tried seemed just as afflicted by lifeless steering as the 320d – a failing that's somehow more of a shame on a car that's clearly designed to please enthusiasts. The planted nature of the four-wheel drive chassis also makes it feel a bit less playful than some will expect from a fast 3 Series, and the Mercedes-AMG C 43 has more character.
One of the most intriguing versions in the range, the BMW 330e has both a 2.0-litre petrol engine and a powerful electric motor. Combined, these provide up to 249bhp and get the 3 Series from 0-62mph in six seconds. That's not quite the end of the story, though, because when Sport mode is selected, there's something BMW calls ‘XtraBoost’, summoning a further 41bhp from the electric motor - provided there's enough charge in the battery pack.
It feels quick, even if the petrol engine can sound a little strained under hard acceleration. The rest of the time the 330e is just as good to drive as other versions, and of course, at low speeds it's incredibly quiet. You'd be hard pushed to notice the extra heft of the 330e either, because its engineers seem to have disguised the weight of its batteries and extra tech remarkably well. It has sharp steering and excellent handling.