Next year will be a great time for BMW will begin offering the 2012 Z4 sDrive28i with TwinPower turbo and direct injected 2.0-liter inline cylinders.
The attachment points are used to the outgoing six-cylinder and the current turbocharged 3.0-liter twin who fit the same four turbo power to hold in place. The product is an impressive weight balance from front to rear 47.3/52.7, an improvement – depending on your perspective – of 47.9/52.1 in the six-cylinder model.
The new N20 is the first four-cylinder engine to take advantage of the recently revealed BMW’s modular engine program, and it is the same mill earlier this year we sampled in the not-for-US-consumption X1 xDrive28i. Power remains almost unchanged in the Z4, with 240 hp comes at 6,500 rpm and between 5,000 and 260 pound-feet of torque available between 1,250 and 4,800 rpm. Although the new N20 is 15 hp compared to the six, torque is up to about 40 lb-ft. And the extra juice is clear when you mash the accelerator.
BMW claims the Valvetronic-equipped four will hit 60 mph in 5.5 seconds, while the new eight-speed automatic gearbox does the deed in 5.6 seconds – a decrease of 0.1 and 0.4 seconds, respectively, over the six-cylinder. And as you’d expect, overall weight is down as well, with the new four-cylinder Z4 tipping the scales at 3,252 pounds, or about 33 pounds less than the outgoing sDrive28i.
Predictably, that minimal weight loss can’t be felt from behind the wheel, but the extra grunt is front and center. There’s a hint of turbo lag below 2,000 rpm when you’re lining up for a pass, but as soon as the single, twin-scroll turbo starts huffing and puffing, the Z4 accelerates more authoritatively than the six. Driving the old and new models back-to-back, we also noticed slightly less dive and squat from the mildly reworked suspension (BMW isn’t saying what’s been done, aside from tweaking the springs and shocks for the new weight balance), but that’s probably more a product of the box-fresh four-cylinder compared to the slightly abused previous generation tester.
Naturally, you want numbers, but BMW is only giving one for now: $48,650 (plus $875 for destination). That’s an increase of $1,200 over the outgoing model, but for 2012, Bluetooth and USB integration, along with trunk-through loading and an alarm system, all come standard, so the price bump is nearly a wash with the new equipment. As for the other figures you’re after, well, BMW isn’t giving up fuel economy estimates just yet. With the (surprisingly abrupt) start-stop system fitted to the Z4 sDrive28i, BMW claims that fuel efficiency is up by 20 percent over the six-cylinder in the EU test cycle, but that could go either up or down when the EPA estimates arrive later this year. Figuring the outgoing model managed 18/28 mpg city/highway, it’s safe to assume the four-cylinder should ring in around 22 mpg in the city and 33 on the highway.