Detroit — Ford hopes to add some muscle to its product lineup this fall with the introduction of its new Thunderbird SC, a performance version of the company's ever-popular sports coupe. It could mark the rebirth of the supercharger. The T-bird and its near-look-alike cousin, the Mercury Cougar, are key products for the Ford Motor Company. Although their combined sales generally total no more than about 250,000 units - about 10 percent of the company's new-car volume - they were pivotal in helping the automaker make its rebound from previous poor sales.
In late 1983, the Thunderbird and Cougar ushered in Ford's trademark aero look, the softly rounded features that stood out against the hard body lines of competitors' products. Ford quickly won a reputation as the auto industry's styling leader.
The new models mark the first complete overhaul of the T-bird and Cougar in five years, a redesign that reportedly cost more than $800 million.
``There are only six carry-over parts,'' says Ross Roberts, general manager of the Lincoln-Mercury division.
The styling of the two cars takes the concept of aerodynamics several steps further; their lines are even more rounded, with lower-slung noses and steeply raked windshields.
Aero styling does have its price. By dropping the nose of the two models, Ford no longer had room for the big 5-liter V-8 engines that it used in its previous high-performance versions.
One alternative was to reintroduce a turbocharger option. Turbos are popular ways to squeeze V-8 performance out of four- and six-cylinder engines these days. Instead, Ford took a cue from the past and, with the top-end Thunderbird SC (for Super Coupe) and Cougar XR-7, buyers will get a supercharger.
The difference between a turbo and supercharger is subtle but distinct.
Both of the systems use fans to greatly compress the air that rushes into the engine's combustion chamber. The result is a more volatile fuel mix and a bigger bang per cubic liter.
The turbo's compressor fan is powered by exhaust gases turning a separate but connected turbine. The advantage is that no power is robbed from the engine itself. The disadvantage is that at low r.p.m.'s, the turbo contributes little extra energy, the so-called ``lag'' that turbo drivers know all too well.
The supercharger, on the other hand, is driven directly by the engine itself. Though this takes away some horsepower, the supercharger doesn't suffer from low-end lag, more than making up for the power it drains away.
In the case of the Thunderbird and the Cougar, the 3.8-liter supercharged V-6 engine will deliver 210 horsepower, 70 more than in normally aspirated models.
Ford isn't the only automaker to revive the supercharger, which was popular in the 1930s and '40s. It is in limited use by Toyota on one version of its MR-2 sports car. But this marks the first use by one of the Big Three in three decades.
In the past, mechanical problems nearly pushed the supercharger into oblivion, and Ford's decision to use the concept took many by surprise. In fact, the automaker has had some problems making its superchargers live up to tough reliability standards.
Some sources say Ford was forced to ``tune down'' the horsepower of the SC engine to keep the supercharger from burning out prematurely. But Tom Wagner, Ford division general manager, says he is confident about the reliability of the new engine package.
``With the success we've had, we're not going to jeopardize that with a product we're not sure of,'' he said emphatically during a recent program in which the new cars were unveiled for the press.
Despite that show of confidence, Ford has not officially announced plans to mate a supercharger with any other product, though company sources say that could happen in the next few years.
The supercharged versions of the Thunderbird and Cougar will carry a fairly hefty premium. Though prices haven't been announced, Ford officials say the top-end models will cost about $20,000.
Will buyers go for it?
Yes, says Art St. Antoine, an editor with Car and Driver magazine.
``Everyone who has driven the T-bird is just blown away by it,'' Mr. St. Antoine says. He adds, however, that ``I was disappointed by the fact that the car has gotten quite a bit heavier.''
In this era of cheap fuel, with buyers clamoring for more room and with government regulators showing a willingness to bend fuel economy standards, the '89 Cougar and Thunderbird are bigger overall, and they have added about a quarter-ton more weight.
Still, with initial reviews highly favorable, the automaker expects to sell from 260,000 to 280,000 of the two models in 1989. If anything, volume could be limited by Ford's production capacity.
Ford has seen such a marked growth in sales over the past five years - 61 percent since 1983, or triple the overall growth of the new-car market in the United States - that its factories are strained to the limit.
Since 1985, Ford has added about a half-million units a year of production capacity by improving productivity at its factories. It has gained a nearly equal amount by sourcing some cars from a plant in Mexico and from the new plant run by its Japanese affiliate, Mazda Motors, in Flat Rock, Mich.
But there may be little more room for growth unless Ford plans to take the costly step of adding another plant of its own. Although that idea is under consideration, as it has been for several years, Ford appears to be clearly concerned that such an investment might go into operation just in time for the arrival of the long-expected downturn in new-car sales.