July 31, 2012
Manufacturer’s web site
Review and photos by Greg Wilson
2012 BMW 3 Series
Of all the changes to the redesigned 2012 BMW 3 Series sedan, the most significant and controversial is BMW’s decision to switch from a normally aspirated inline-six-cylinder engine to a turbocharged four-cylinder engine in the 320i and 328i. It’s both a technological and psychological leap and a somewhat risky one given BMW enthusiasts’ special attachment to their inline sixes—and the fact that the 3 is BMW’s most popular model. Sure, we know Audi has had a turbo-four for almost two decades and even Mercedes recently popped a 1.8L turbo into the base C 250, but BMW’s straight-sixes are almost a religion amongst the faithful.
2012 BMW 328i Luxury. Click image to enlarge
Unsurprisingly, BMW’s decision was motivated by the need for better fuel economy and emissions reductions, goals that also motivated BMW to replace the previous six-speed automatic transmission with an eight-speed. In fact, the ZF eight-speed auto is now standard in the 328i and the six-speed manual is optional. (Thank God they didn’t go bananas and insert a CVT into the drivetrain. Sorry, Audi.)
So how does the new turbo-four compare to the inline-six? Going by the numbers, it all looks good for the 241-hp 328i: more horsepower, way more torque and significantly better fuel economy with both the manual six-speed and eight-speed automatic transmissions (the 320i has the same motor with less horsepower—181). Throttle responsiveness at low revs has improved due to the increased torque. The previous 3.0L inline-six developed 200 lb-ft of torque at 2,750 rpm while the new turbo four offers 260 lb-ft starting at just 1,250 rpm. The compact 328i Luxury sedan is not only quick over the long haul—0 to 100 km/h 6.3 seconds, a full second faster than last year’s model with the automatic—but responds better in the 30 to 50 km/h range for more spirited city driving. I was frankly surprised at the power coming out of this two-litre engine. And I found it surprisingly quiet under acceleration and normal use—it’s only at idle that the distinctive clatter of a four-cylinder engine is audible.
2012 BMW 328i Luxury. Click image to enlarge
A driver-selectable Sport mode improves the fun behind the wheel with quicker steering, better throttle responsiveness, and revised shift points for improved acceleration (and worse fuel economy). It would be nice if the driver could make this the default setting! For the thrifty 328i driver, a new push-button Eco-Pro drive mode improves fuel economy by making the transmission shift earlier and reducing throttle response. But gosh Heinz, it feels very un-BMW-like.
Despite its many gears, the new eight-speed automatic’s frequent shifts are mostly transparent to the driver, and the engine and tranny seem to work together like two easy-going friends. On the freeway, I observed an engine speed of just 1,600 rpm at 100 km/h in eighth gear on the flat—which goes a long way to explaining the 328i’s improved highway fuel economy—but slightly higher engine speeds when descending hills as the transmission stays in a lower gear for gentle engine braking. A manual shift mode, operated using the shift lever, allows the driver to shift up a gear by pulling the lever back, and shift down by pushing forwards. There are no paddles behind the steering wheel in the 328i, only in the 335i.
The operation of the floor shifter is different from that of most cars: a release button on the handle allows the driver to shift into reverse, neutral, and drive by tapping forwards or back, but to engage Park, the driver must press a button on top of the gear knob. To me, this seems more complicated than it needs to be.
Fuel economy improvements when equipped with the eight-speed automatic are impressive, according to official figures: 8.0/5.3 L/100 km city/highway compared to 11.0/6.9 with the previous six-speed automatic. With the six-speed manual, the figures are 9.0/5.6 city/highway compared to 10.8/6.9. Some of the credit for the improved city mileage must go the new engine start-stop feature that shuts off the motor when the car is stopped in traffic. This is a feature we’ll soon see in many other cars, but like the other reviewers who’ve driven the 328i, I didn’t like the time-delay and the jerkiness of the automatic restart—this is something that needs refinement. Fortunately, it can be deactivated, but it has to be done every time you restart the car after turning off the ignition.