DEARBORN, Mich. - Here we go again: in a repeat of not-too-successful experiments of the past, automakers are once again going to see if luxury-car buyers will go for 4-cylinder engines.

General Motors Co.'s Buick will offer base version of its new 2010 LaCrosse upper-midsize sedan later this year with a 4-cylinder under the hood. GM execs have said the Cadillac division won't rule it out.

The Lexus HS 250h goes on sale next month and although attention will focus the fact it's a hybrid, the HS 250h still is working with a 4-cylinder engine - a first for Toyota Motor Corp.'s premium division.

Audi AG, with one of the industry's most solid small-engine reputations, will push the envelope with a new 4-cylinder variant of its 2010 A5 coupe, which the company says already is on the way to U.S. showrooms.

BMW, the world's biggest maker of luxury cars, probably will bring back four-cylinder engines, the company's top U.S. engineer was quoted as saying last week.

And here at Ford Motor Co.'s headquarters, the company's chief powertrain executive says there's no functional reason 4-cylinder power couldn't be considered as a viable option somewhere in the Lincoln premium-brand lineup.

New-Age Sensibility Or A Repeat Train Wreck?

Recent - and not so recent - examples of the often uncomfortable marriage between luxo-vehicles and 4-cylinder engines are numerous: the Cadillac Cimmaron. BMW's 318. The Mercedes-Benz C230.

The difference this time from failed attempts of the past: more-sophisticated technology. And different socio-economic and environmental attitudes that may predispose buyers to accept less sheer performance as a tradeoff for improved economy and environmental impact.

New turbocharger designs and direct fuel injection are advanced new technologies that can combine, as with Ford's much-hyped "EcoBoost" engines - to pump up the output of 4-cylinder engines to a level unthinkable with contemporary technology available for the 1980s Cimarron.

"Specific output" is the term for how powerful and engine is in relation to its displacement; forced induction such as turbocharging and torque-pumping direct injection bring an almost entirely new level of power that can be produced from just four cylinders.

Not long ago, 80 horsepower per liter of displacement from a conventional V6 was pretty formidable power. Now, Ford engineers speak of 115 horsepower per liter - or better - from a 2-liter EcoBoost 4-cylinder engine coming next year. A slightly larger 4-cylinder could thump out 300 horses or more - more than equal to today's best V6s and even challenging some V8s.

The Times Are A' Changin'

The technical ability to get expected levels of luxury-vehicle performance from 4-cylinder engines is there. But will customers accept the idea of 4-cylinder power?

"I think the days of counting up cylinders are over," Barb Samardzich, Ford's vice president for global powertrain engineering, told AutoObserver.

"We have a set of DNA (for luxury or luxury-sport models). As long as we're meeting that DNA, I think the customer will accept that (a 4-cylinder engine)."

At Buick, the proposition for the 2010 LaCrosse might be a little more nip-and-tuck: the LaCrosse's 2.4-liter 4-cylinder uses torque-boosting direct injection, but is not turbocharged. The engine develops 182 horsepower and the 4-cylinder LaCrosse will weigh in the neighborhood of 3,900 pounds.

Susan Docherty, vice president for Buick-Pontiac-GMC, thinks LaCrosse buyers opting for the 4-cylinder - it's offered only for the base LaCrosse CX trim level - will be more focused on the projected 20 miles per gallon city/30 mpg highway fuel economy than on absolute power.

"It doesn't matter whether you're a premium buyer," Docherty said of the new rules in the luxury market. "Everybody's concerned about fuel economy."

Lincoln hasn't pulled the trigger on a 4-cylinder engine just yet - it's using 3.5-liter V6s with EcoBoost technology for the 2010 Lincoln MKS and MKT to replicate V8 power without the corresponding fuel consumption - but Samardzich said there's no engineering reason an EcoBoost-enhanced 4-cylinder couldn't be used by Lincoln. The brand just has to be careful to avoid a potentially overzealous application.

Four-cylinder power "has possibilities," for the luxury-sport market, Samardzich said.

"I think expectations on fuel efficiency and environmental consciousness are there," for premium-car customers, she added, but says marketing plays a key role. "You have to have a dialogue around the attributes you're giving the customer."

"I think there's going to be a shift," says one GM engineering source. "There are people who are never going back to big engines."

Samardzich said Lincoln marketers would have to make the final call on EcoBoost 4-cylinder power for future Lincolns, but cautions that even high-tech 4-cylinder power has limitations: she sees potential for vehicle sizes up to the C-D range, but believes full D-segment-sized vehicles would be too large for any kind of 4-cylinder power.

"The true D-size is a stretch," she said, conceding that Ford engineers and marketers are having discussions right now about where in the Ford and Lincoln model lineups 4-cylinder engines might have potential.

Fuel economy is going to be important, Samardzich said, even for luxury buyers. But she insists Ford won't assume any compromises from a premium-vehicle buyer about performance, either.

"You can't let your customer down," she said. "Not in this business."