Driven: 2012 Buick LaCrosse eAssist

Hybrid or V-6? That's the choice Buick is offering LaCrosse buyers for 2012, and neither option is extra-cost. The V-6 is a 3.6-liter that makes 303 hp, which is considerably more power than you get with the 4-cylinder hybrid. The V-6 also is alone in offering the option of all-wheel drive. The hybrid, which Buick calls eAssist, is a mild hybrid, in that it can't propel the car solely on electric power, even at low speeds. Instead, as the car's name implies, it assists with 15 hp and 79 pound-feet of torque, helping the 182-hp four-cylinder accelerate this 3835-pound car. More importantly, it allows the engine to shut down at stoplights and then smoothly and instantly restart, aiding the cause of fuel economy. Speaking of miles per gallon, the LaCrosse eAssist is EPA rated at an impressive 25/36 mpg. That's much better than the 19/30 mpg for unassisted four-cylinder offered previously, not to mention far more economical than the V-6's 17/27 mpg. A six-speed automatic, instead of a stepless CVT, gives the LaCrosse conventional-feeling throttle response rather than the elastic response conveyed with a CVT. Speaking of response, though, with the LaCrosse's ultra-tall final drive ratio, you really have to put your foot into it to awaken this powertrain. On a positive note, the 2.4-liter Ecotec --which, like many direct-injected four-cylinders, is not known for its mellifluous sound quality -- here has been so effectively muffled that could almost be a V-6, at least under 3000 rpm. And the car is very quiet overall. If that's what you'd expect from a Buick, then so too is the chassis. The car comfortably sops up bumps but would benefit from greater damping of body motions, to quell squat and dive. The electrically assisted power steering is rather numb and artificial-feeling. As in many other hybrids, the eAssist battery pack is located behind the rear seat, and it takes up a bit of trunk room (as do the old-fashioned-style gooseneck hinges and their big plastic housings). If trunk space is not this big sedan's strong point, rear-seat space certainly is. That's not surprising given that in the Chinese market, where the majority of Buicks are sold nowadays, the LaCrosse might often be a chauffer-driven car. Those riding in back will find headroom just adequate under the sloping roofline but there's a generous 40-plus inches of legroom. A rear-seat entertainment system is also available. In all, the eAssist system is a very painless and unobtrusive way to get compact-car gas mileage in a big, comfortable sedan. Given an even choice between it and a more powerful V-6, it will be interesting to see which way Buick shoppers vote.