MUNICH — We'll never know how many BMW owners suffered a severe mental break and began wearing their underpants outside their clothes and talking to their Cheerios on account of iDrive, the company's famously frustrating multi-function rotary controller. All we know for sure is that previous versions of iDrive did for human factors engineering what big rocks did for Sisyphus.
The problem iDrive was meant to solve -- bringing a wealth of navigation, phone, entertainment and vehicle functionality into the cockpit without making it look like the flight deck of a 747 -- was made worse because the system was so gallingly uncooperative. Yes, you could learn it and yes, it did work, provided you invested time in the Berlitz School of iDrive. For most people, though, it was maddening. I called it the Oy-Drive.
But now, for model year 2009, the cure has arrived: In the redesigned 7 Series and 3 Series introduced to the media this week, BMW has fixed iDrive.
The new system, with which users leaf through stacked graphical menus, moving left to right toward the desired selection as if on a Mac computer, works beautifully and intuitively. The display -- a scintillating 8.8-inch LCD screen -- is a stroke of high-resolution lightning. The controller -- the big rotary knob -- has itself been reformed, now clustered with four direct-selection buttons (CD/radio/phone/navigation system) and three control buttons, including the blessed "Back."
My opinion of these cars has thus been transformed. Obviously, the Werks makes finely fettled adrenaline pumps, cars with snap-to-line precision, ballistic quality, exquisite handling and road holding, but I could never quite embrace BMWs when it took me 10 minutes to find the nearest In-N-Out Burger on the nav system. With the new car's more elegant electronics, all is forgiven.
The other big news out of Munich is the introduction of a 50-state-legal diesel engine for the 3 Series, in the 335d. This engine -- a twin-turbo 3.0-liter straight six producing 265 horsepower -- radically alters the gestalt of the 3 Series (it will also be available in the X5).
Where once the furious, bees-on-fire sound of a high-revving gas engine poured into the cabin, now the turbo-diesel sets the deck plates atwitter with a dark, seismic churn. Where once it was high-rpm, flirting-with-redline horsepower that punched you in the back, now it's low-rpm torque: A big, fat 425 pound-feet of torque (between 1,750 and 2,250 rpm) swats you like a humpback's tail as you round a corner, unwind the wheel and open up the e-throttle.
(The briefest explanation of the difference between torque and horsepower is in order here: Torque is twisting force. Grab a doorknob and twist. Voila. Torque. Engine torque is the force that causes cars to accelerate. Horsepower is a product of some arithmetic that multiplies torque by the rotational speed of the thing being twisted, in this case the engine crankshaft. The more engine speed, or rpm, the more horsepower.
We will stop now before my high school physics teacher demonstrates torque by rolling over in his grave.
The metabolic difference between a gas and a diesel powertrain turns the conventions of sport-driving on their head. In a several-hours transit of the Jaufenpass between Austria and Italy -- a picture-postcard idyll, a thread of asphalt set amid frozen Alpine ramparts -- I quickly realized holding gears in the 335d and wringing the motor out was of no use. Besides, even in manual shift mode, the BMW's six-speed automatic transmission up-shifts well short of the 5,000-rpm redline.
Also, it doesn't do a heck of a lot of good to downshift to first or second gear coming out of hairpin and nail the throttle, as you might do in the gas-powered 3 Series. The diesel's tugboat torque can easily overwhelm the tires' grip, setting off the traction control and causing the car to dither and slow down. Better to leave it at a higher gear and open the taps. When you do, a big gathering surge grabs the car in a kite-wind of acceleration. That's nice.
The object of this exercise is to deliver BMW-worthy performance (zero to 60 mph in six seconds and an electronically governed top speed of 134 mph) with high fuel economy: 23 miles per gallon city and 36 mpg on the highway.
Just a couple of years ago, these sets of numbers would have seemed as irreconcilable as Charlie Sheen and Denise Richards. But it wasn't easy. To pass California's strict NOx emission standards, the 3 Series -- like other high-performance German oil burners -- uses a urea-injection exhaust treatment system. The 20-liter reservoir (note the circular access panel on the left-rear quarter panel) should be sufficient to last the car between 11,000-mile service intervals, if you aren't cavorting sehr schnell.