Overall, the four-cylinder LaCrosse will further expand the model's considerable appeal, but its modest power means it's unlikely to become a significant part of the mix.
In terms of base price, the four-cylinder saves you only $840 over the V-6-powered CX, but the mileage bump is a more significant 2 mpg in the city (to 19 mpg), 4 mpg on the highway (to 30 mpg) and a combined 2 mpg improvement in mixed driving (to 23 mpg).
Modest Power, at Best
The 2.4-liter four-cylinder generates 182 horsepower, versus the 3.0-liter's 255 hp (252 hp with all-wheel drive) and the 3.6-liter's 280 hp. The CX comes only with front-wheel drive and either the four-cylinder or 3.0-liter engine. The CXL comes with front- or all-wheel drive powered by the 3.0-liter, and the CXS comes with front-wheel drive and the 3.6-liter.
As for its acceleration, the smaller engine rides the line between modestly powered and underpowered. As someone who knows a driver can adapt his expectations and driving style to a car, I was satisfied with it. However, I know Americans are power-hungry and all too quick to deem unsafe any car that can't blow away a top-fuel dragster in the passing lane. Here in the Illinois flatlands, the car was more than workable, though I expect some shoppers will disagree. A fully loaded CX four-cylinder on hilly terrain, however, would be another story entirely. Even I don't think 2 extra mpg and an $840 discount are worthwhile in that scenario.
The drivetrain's character is pretty good overall, and I give extra credit for how quiet the engine is, even under full acceleration. To tap into maximum power, four-cylinders have to rev pretty high, and people tend to equate the accompanying noise with "straining." In truth, the engine is just doing its job, but the drama can definitely give a bad impression. The LaCrosse overcomes this sensation by keeping engine noise to a minimum. Historically, GM's Ecotec family of four-cylinders hasn't been a paragon of refinement in terms of noise, vibration and harshness. This new execution is nicely done.
Having six speeds in the standard automatic transmission is key to making the small engine viable in the LaCrosse, and though it serves its purpose, I wish it would respond more quickly to requests for passing power. It often hesitates before kicking down, and sometimes it gets confused and hunts for a gear. It's likely most drivers won't notice these things; I'm less accepting of transmission or throttle hesitation than I am of modest power. I also felt some slight thunking when getting on or off the accelerator at low to medium speeds, but again, that might be a picky car reviewer thing.