For a very long time, the BMW 3 Series was the car to beat in the market for premium compact sedans. Recently the competition has caught up, with the likes of the Mercedes C-Class and the sharply styled Lexus IS encroaching on BMW's turf. To try and elevate the 3 Series above its rivals, BMW has given the car a styling refresh and introduced a three-cylinder motor and plug-in hybrid option.
All of the engines in the refreshed 3 Series lineup have been reworked to combine better fuel economy with more power. On the diesel front, the 316d, 318d and 320d have all been fitted with revised turbochargers to offer better throttle response. The 316d's motor produces 85 kW (116 hp), with the engine's peak 270 Nm (199 lb.ft) of torque available between 1,250 and 2,750 rpm. This is 25 kW (34 hp) and 50 Nm (37 lb.ft) less than the more expensive 318d's engine makes, and well down on the 140 kW (190 hp) and 400 Nm (295 lb.ft) of torque produced by the 320d.
In spite of the increase in power, CO2 emissions and fuel consumption figures are both down across the range, with the EfficientDynamics tuned 320d burning a miserly 3.8 l/100km (74.3 mpg) on the combined cycle.
The bottom end of the petrol line-up is where BMW has made the biggest changes to the 3 Series range. The updated 318i is fitted with a 1.5-liter three-cylinder motor producing 101 kW (136 hp) and 220 Nm of torque – the first time that BMW has slipped a three-cylinder engine under the bonnet of a mid-size car. Bavaria's engineers are keen to point out the three-cylinder engine's light weight and compact nature, although it remains to be seen whether BMW buyers will be comfortable buying a sedan with the engine from a Mini under the hood. Premium or not, the 1.5-liter engine is economical, with fuel economy of just 5.5 l/100km (51.4 mpg) and CO2 emissions of only 137 g/km. Performance is also impressive for such a small engine: 0-100km/h (62mph) in a reasonably sprightly 8.9 seconds.
At the other end of the range, BMW has replaced the top-end 335i with the 340i. Power comes from a new turbocharged inline six, which produces 240 kW (326 hp) and 450 Nm, enough to shoot it from 0-100km/h (62 mph) in 5.1 seconds – similar to the 4.9-seconds it takes its Mercedes C450 AMG rival to hit the same mark. As with the rest of the range, the 340i emits less CO2 than the model it replaces too, with its 152 g/km figure representing an improvement of over 10 percent.
As of 2016, the 3 Series range will also include the 330e plug-in hybrid, designed to rival the hybrid options Mercedes offers on its C-Class range. According to BMW, the maximum output of the 330e's hybrid drivetrain is pegged at 185 kW (252 hp). Both Mercedes and BMW claim fuel economy of 2.1 l/100km (112 mpg) for their hybrids, while the BMW will travel 35 km (22 miles) on battery power alone – 4 km (2.5 miles) more than the C350 plug-in hybrid can manage.
As well as updating the 3 Series' engine lineup, BMW's has focused on lifting cabin quality with extra chrome highlights, a redesigned center console and improved materials on touchpoints around the cabin. There's also an upgrade to the navigation system, which boots up and finds routes faster, as well as offering improved 3D graphics.
Externally, the updates are fairly subtle. Full LED headlamps are now an option, and the graphics of the taillights have been revised to make the car seem wider on the road. The front apron has also received a rework to include the sensor for BMW's active cruise control system.
The update also extends the the 3 Series' suspension and damping, with stiffer suspension and a revised damping system.
The updated 3 Series range will be available with a six-speed manual or an eight-speed automatic gearbox, while BMW's xDrive all-wheel drive system is optional on the 320i, 330i, 340i, 318d, 320d and 330d.