2012 BMW 328i road test: Nothing to fear from switch to four cylinders

2012 BMW 328i sedan

2012 BMW 328i sedan

There are some questions that need answering in any assessment of the new 2012 BMW 328i sedan.

1. Can buyers be satisfied with the turbocharged four-cylinder  engine that replaces the silky smooth in-line six as the base powerplant?

2. Is the new, marginally softer independent suspension an indication that the 3 Series has lost a bit of its mojo?

3. Is slightly bigger slightly better?

4. Will the price, which can spiral from a base of $34,900, according to the the test BMW’s window sticker, to well over $50,000, move this BMW beyond what many 3 Series buyers are willing to pay?

The answers, I suspect, are (1) yes, (2) yes and no, (3) it depends, and (4) possibly.

Let’s take a closer look.

The biggest concern of BMW lovers, owners and intenders is that the new engine in the 6th generation 3 Series sedan is inherently rougher, with a less premium feel, than 6-cylinder models. These folks need not worry.

2012 BMW 328i instruments

2012 BMW 328i instruments

Through sound damping, the use of balance shafts and other technical wizardry, the BMW engineers have created a powerplant that produces no discernible shakes, shudders or other unpleasantness.

On start-up it is not exactly as smooth as a silky six and it is a bit noisier from outside the car, with a slightly diesel sound, but those potential annoyances barely reach the passenger quarters.

More importantly, any hint of the four-cylinder engine’s inherent roughness disappears on acceleration and it offers other benefits which, in my mind, make it more desirable than its predecessor. In fact, for many buyers it should render needless the optional and more expensive turbocharged, 300-horsepower in-line six.

By the numbers, the 2-liter, turbocharged four generates 240 horsepower and 255 pound-feet of torque, compared to 230 horsepower and 200 pound-feet for the discontinued in-line six.

Teamed with an eight-speed automatic transmission it will vault the 328i from a stop to 60 mph in 5.9 seconds and on to an electronically limited 130 mph. You straight shifters can make it from a stop to 60 mph in 5.7 seconds with the six-speed manual transmission. Who really needs anything more?

MW 328i front seats

MW 328i front seats

But, wait, there’s more to this turbo 4-cylinder than the extra pep it produces. It can also be surprisingly frugal, able to achieve 24 mpg in the city and 36 on the highway, according to the Environmental Protection Agency.

This efficiency is in large part the result of the car’s 8-speed automatic shifter and what BMW refers to as Driving Dynamics Control. By tapping a switch on the center console, a driver can activate ECO PRO, which can improve fuel mileage by up 20 percent as the electronics retard accelerator response, force quicker upshifts and delay downshifts.

In addition, the battery is recharged through regenerative braking and the system can minimize power usage by the BMW’s accessories, such as lowering  air conditioning output.

The driver can significantly reduce fuel consumption, too, by reacting to special displays in the instrument cluster that show how to maximize driving efficiency.

However, there is little good to say about the new-for-2012 automatic stop/start system that cuts the engine at traffic stops and then turns it back on when the driver releases the foot brake.

It is rough, it does cause a shudder and the engine sometimes re-fires while the car remains stopped with the driver’s foot on the brake. For me, the annoyance outweighs the advantage of minimally greater fuel efficiency. Fortunately, the system can be disengaged.