Buick, BMW Put a New Focus on Four-Cylinder Engines

It's inevitable: At some point in time, the auto industry is going to have find a practical, affordable alternative to petroleum-based fuels. But until then, OEMs will need to continue discovering new ways to squeeze more efficiency out of plain old gas- and diesel-powered engines.

At General Motors, for one, it looks like turbocharging will be a big part of that effort. News continues to trickle out about the upcoming Buick Regal (pictured left), which is scheduled to go on sale in the second quarter of 2010, and among the latest factoids is that the up-level engine on GM's new "sport sedan" will be a turbocharged four-cylinder engine capable of producing 220 hp.

According to the General, the turbo Regal also will be good for 29 mpg on the highway, just off the 30 mpg highway expected from the non-turbocharged four-cylinder that will be standard on the entry-level model.

General Motors is really playing up the Regal's "bred on the autobahn" origins as marking a sea change in Buick's direction, and it really could have been '” but not for the reasons GM is telling us.

Yes, the new Regal built on the same platform that underpins the 2009 Opel Insignia, which has won a ton of awards overseas and is currently, per GM, the best-selling midsize sedan in Europe. (Needless to say, the ability to develop a platform like this is a big part of the reason GM decided to hold on to Opel.)

But what could have really set the new Buick apart from its competition would have been a decision from GM to give up on the horsepower arms race, at least in this segment. I mean, if the 2010 Regal were designed to have best-in-class fuel efficiency, the fact that it is well under-powered compared to its rivals wouldn't necessarily be a problem. A Regal that could out-handle other entries in the segment and outperform them at the pump would be something to brag about, and it would certainly attract customers.

It would be going the Mazda MX-5 Miata strategy one better. The Miata, along with the Mazda RX-8, don't win fans because they're necessarily the fastest vehicles in their segments, but because they're among the best handling and provide a class-leading driver experience. If the Buick Regal could stake out this positioning among sport sedans '” an admittedly tough task '” it would offer a nice "hook" with which to pull in buyers. And if the Regal did that while also providing great mileage, so much the better.

Except that's not going to happen. Let's bring the Acura TSX into the picture for comparison's sake. (The TSX and Volvo S60 are both named by GM as key rivals to the Regal. However, the current S60 is soon to be replaced, so it doesn't make sense to compare the Regal with the outbound Volvo, and full specs aren't available for the new one.)

In base-level trim, the Buick offers less horsepower (182 for the Regal; 201 for the TSX) in a heavier package (3,600 lbs. vs. 3,470 lbs.) that gets slightly worse gas (20/30 vs. 21/30).

Moving up to higher-performing entries, the story gets a little better for the Buick. The TSX uses V6 power in its upper-level trim, which adds enough weight to bring the Acura up above the 3,600-lb. mark; but that's offset by an engine that delivers 280 hp, 60 more than in the Regal turbo. And on the mpg side of things, the V6 Acura is rated at 18/27, two mpg shy of the Regal's highway number. (GM isn't talking city mpg for the Buick yet.)

Put it all together and, on paper at least, the Buick gets the worst of this comparison in both measures of performance: power and efficiency. On the hand, the Buick will offer some cooler tech toys than the Acura and it certainly will look a whole lot better. But it's also going to look like a missed opportunity, at least IMHO.

And as long as we're looking at sport sedans today, we better see what BMW is up to '” and the surprising answer is: 68.9 mpg. That's the combined fuel-efficiency number the new BMW 320d achieves on the European testing cycle. The key here is that that little "d" on the end of the car's name stands for "diesel." Well, that and the fact that this diesel power will find its way over to the U.S. in the not-so-distant future.

Yep, the Bavarians are now on record as saying future U.S. versions of the popular BMW 3-Series will offer four-cylinder diesel engines, and that will be exactly the kind of "hook" that the Regal claims to offer but doesn't. Even though it could.

Because it turns out that '” over in Europe '” the Opel Insignia happens to be offered with a diesel of its own. True, it "only" gets 54.7 mpg on the European cycle, but I'm betting that's a number that Buick owners could live with.