US two-seater cars may weigh as little as 1,200 pounds and get 80 miles per gallon

You can't see them today, perhaps, but a phalanx of two-rider cars is barreling down the pike. By the mid-1980s, some auto-industry forecasters say, from 15 to 25 percent -- maybe more -- of all new vehicles coming off US assembly lines will seat two persons and no more.

The first of the two-seater vanguard will come around the bend early next year.

Typical two-passenger cars will weigh between 1,500 and 1,800 pounds, with some possibly as light as 1,200 pounds -- compared with about 3,600 pounds for a full- sized model today. They'll get from 50 to 80 miles to a gallon of gas, and some may even be propelled by engines with less than four cylinders.

Some of these sub-subcompacts will almost certainly be battery-powered electric cars.

A few may even be hybrids with a battery pack plus a very small one-or two- cylinder engine to keep the batteries on charge during vehicle operation, thus increasing the range.

As a group, they'll be known as "commuter cars" and their major use will be to get the owner to and from work as well as for shopping trips close to home.

Today, there are a few two-passenger cars on US roads, but they aren't of the low-cost, lightweight design of the forthcoming commuter vehicles.

The Chevrolet Corvette, introduced as a 1953 model, always has been a two-seater. A little closer to the design of future commuter cars, however, is the base Chevrolet Chevette. Known as the Scooter, it comes with or without the rear seat.

Among domestic carmakers, Chevrolet stands alone in offering two-passenger models. All other such cars are imported from Europe or Japan as of now.

West Germany offers the Porsche 924, the current model. It was preceded by a long line of impressive little luxury cars with seating for two. From Britain there's the Spitfire, the TR-7 and TR-8 from Triumph, and the MGB, all from BL Ltd., formerly known as British Leyland.

Italy's Fiat offers the Spider 2000 and the X 1/9. From Japan comes the Datsun 280-ZX and the rotary-engine Mazda RX-7 which compete in many respects with the Chevrolet Corvette.

All of these cars, however, are performance cars and contrast greatly with the two- seat cars of the future in respect to both fuel economy and initial cost. Most of today's two- seater cars sell for $10,000 or more and get a fraction of the mileage to be expected from the minicars of tomorrow.

The so-called "commuter cars" will be lightweight, inexpensive to buy and maintain, and will have only moderate (but adequate) performance capabilities. Also, they will go farther on a quart of fuel than many cars now go on a gallon.

For the most part they will have four wheels although tricycle types are possible, with the single wheel either in front or to the rear of the vehicle. The largest engines for two-passenger cars will have four cylinders, but three-cylinder engines offer certain advantages, particularly in miles-per-gallon performance -- and they could prove to be the most popular.

For the lightest models -- those in the 1,200-pound range -- two-cylinder engines are a possibility either as the sole method of propulsion or to drive an electrical generator and recharge the batteries of an electric vehicle.

Until quite recently, US carmakers were extremely disinclined to talk about future products. Today, by contrast, it seems to be the operating policy of the companies to talk about car models down the road.

Ford will come out next spring with a sports spinoff of the all-new Ford Escort and Mercury Lynx. For some time industry observers had assumed that the car would have seating for at least four people. Last month Ford chairman Philip Caldwell revealed that next spring the firm would offer "a two-seater sports coupe that will incorporate the magic of the 1955 Thunderbird and the mass appeal and affordability of the 1965 Mustang."

The EXP-series cars, as the sport coupe is now identified, will be the beginning of the two-passenger concept at Ford in recent times. Ford tried the two-seater idea with the first Thunderbird in 1955, Ford's response to the 1953 Chevrolet Corvette. But while the Corvette stayed with the two-passenger concept, Ford abandoned it in 1960 and added a back seat to broaden the car's appeal.

As two-seaters, the 1981 1/2 Ford EXP-series cars will be rather wide of the mark for similar autos from the firm in mid-decade. The EXP autos reportedly may have a slightly shorter wheelbase and overall length than the Escort/Lynx. But weight won't be down sufficiently to give these cars much greater fuel economy than the regular Escort/Lynx.

Perhaps closer to what is expected to become classic two-passenger car design is a model due from GM's Pontiac division in the fall of 1982 as an '83 model. Like the Ford EXP cars, this one, code-named the "P" car, also will be a sports edition. It appears to be aimed directly at the motorist who's attracted to the Fiat X 1/9. The new Pontiac will have the engine mounted transversely amid- ships where the back seat ordinarily would be.

The "P" car's base engine is expected to be the very thrifty 4-cylinder power plant which will be standard in the 1982-model "S" cars which are slated for introduction next April. The front-wheel-drive "S" cars, to be sold by Chevrolet and Pontiac alone, will replace the Chevrolet Chevette.

Planned use of a subcompact car engine in the two-seater "P" car hints that a high miles-per-gallon rating is one objective of this sporty auto from Pontiac. Still, it will be a long way from the two-seater cars still to come from Detroit.

Far closer to the "commuter cars" that GM will be building in the mid-'80s are those that will use 3-cylinder engines. While the engines may run on gasoline, some of them could operate on diesel fuel instead.

GM's work on three-cylinder engines, which, with a 5-speed manual transmission, reportedly give adequate performance to two- passenger cars that weigh up to 2,000 pounds, dates back to the Arab oil embargo of 1973-74. Considerable work was reportedly done with the 4-cylinder "iron duke" engine that is base equipment for the GM X-cars and one cylinder was deleted.

More recently, the in-line three-cylinder engine work has evolved from the much more advanced 4-cylinder power plant slated for use in the GM J-cars which are expected to go on sale next May. The J-cars replace the Chevrolet Monza and Pontiac Sunbird. Again, one cylinder was dropped.

Another 3-cylinder engine under development at GM is half of the older V-6. The engine block is, in effect, half the V-6, sawed down the middle.

Still another engine, suitable for small, lightweight, two-passenger commuter cars, utilizes a V-6 engine with two end cylinder deleted to produce a V-4.

GM has made no secret of its development work on these engines or on future commuter cars which will use the little power plants. In fact, GM says it plans to achieve a fleet average of 31 miles per gallon for 1985-model passenger cars, substantially higher than the 27 1/2 mpg required by the law.

The automaker has shown two passenger cars, one with a 3-cylinder engine and the other with a V-4. The 1.5-liter, 3-cylinder engine gets up to 60 miles per gallon when operated at speeds between 40 and 55 mph.

More than a year ago, E. M. Estes, GM president, said the firm had made a major breakthrough in the design of electric storage batteries of the type that would be used to power small commuter-type cars. GM also has said that a target date has been set for the introduction of a small electric vehicle -- late 1983 with the auto being designated a 1984 model.

A clay model of a design being considered for the vehicle shows a two-passenger capacity with sufficient space behind the seats for groceries, golf clubs, or similar cargo. All two-passenger autos now being developed provide space for payload as well as occupants.

By 1985, predicts Mr. Estes, all passengers cars built by GM will exceed 20 mpg and at least half will exceed 30 mpg.Clearly, there are going to be a lot of high-mileage commuter cars down the road.

Now only about 1 percent of GM car production gets over 30 mpg.

Chrysler Corporation has said very little about development work on two-rider cars.

Still, Harold K. Sperlich, executive vice- president for engineering and product development, says the firm could have a two-seat sports car as early as 1983. It probably would be a front-drive sports car with a body built in Italy. Too, it would have a high-performance fuel-injected engine with turbocharger and a 5-speed manual transmission.

"This is not looked upon to be a high-volume car," said Mr. Sperlich. Rather , he adds: "It will be a model that will create excitement and contribute image for dealers."

There is evidence, however, that Chrysler is thinking in terms of some less-exotic two- seaters. One model built for recent auto shows was a version of the Plymouth Horizon TC-3, a spyder-type performance car.

At American Motors, development of two- passenger cars has been under way for several years. Richard Teague, vice-president of design, says he is confident that the population of these little commuter cars will grow fast in the mid- to late-1980s. He sees them serving mainly as a second car.

Three-wheeled commuter cars are pretty much ruled out by Mr. Teague because they don't provide the stability of 4-wheel vehicles. Looking ahead, any two-seater cars from AMC would probably be lighter than those expected from GM and the miles per gallon may be higher.

Overall length is seen by Mr. Teague as being "up to" 110 inches, which is considerably less than the length of the GM high-economy vehicles, which measure 138 inches overall.

Mr. Teague also sees a two-cylinder turbocharged diesel which he calls a "mighty fine little power plant for one of these minicars." Small electric cars also are a strong possibility, he adds.

The AMC designer isn't so sure that the first such models on the market will be well accepted by the public. Acceptance may hinge on the price of fuel, he asserts.

Overseas, Volkswagen is working on three-cylinder engines in both gasoline and diesel versions, very likely for smaller, lighter vehicles than the VW Rabbit. Most other European automakers are reportedly developing tiny commuter cars for export to the US. Indeed, several car manufacturers, including firms in Italy, France, England, and West Germany, have had considerable experience building two-passenger cars over the last several decades for their home markets.

This is also true of the Japanese. Some vehicle manufacturers already have two-passenger cars on the roads. Importation of these little autos from Japan (and Europe as well) could probably begin as quickly as they were adapted to meet US standards for safety and emissions.

It could be a formidable hurdle for all these cars, both US and foreign, to clear.