'Slippery' cars of '80s mean more miles to the tank

A slippery car is a good thing. It means more miles on a tank of fuel. Thus, as with carmakers the world over, Volkswagenwerk AG has stepped up its work toward building more slippery cars in the 1980s.

The West German carmaker reports that both its new flagship, the Quantum, and the restyled '82 Scirocco have a coefficient of drag (CD) of 0.38. The Scirocco, for example, has a smaller air intake that is aerodynamically matched to the front spoiler of the car. The Scirocco also uses advanced aerodynamics to provide ''down force'' for greater traction on the wheels in hard, high-speed cornering.

The nonturbocharged Porsche 924 records a CD number (the ease with which a vehicle moves through the air) of 0.34 with a spoiler and 0.35 without one.

A spokesman for Nissan Motor Corporation in U.S.A. asserts: ''It was predictable that many auto manufacturers would get into the coefficient-of-drag numbers game as another way to compete for sales.'' Then he adds that the all-new Nissan Stanza boasts a CD rating of 0.38, coming very close to the sporty Datsun 280-ZX, a sleek two-seat sports coupe with a CD of 0.36

The low CD rating for the Stanza is proof, according to Nissan, ''that a sedan that seats five persons comfortably can have drag no higher than sports cars.

''Design of the Stanza includes a wedge-shaped body, a 'wrap-around' windshield (which gets the front pillars partly out of the frontal slipstream), a sloping hood, low belt line, and above-average total glass area.''

Toyo Kogyo Company Ltd., which builds the Mazda nameplate, says ''there will be more flush bodies and considerable work done on the undersides of all vehicles to reduce drag there.

''Mazda's targets for its future line of vehicles is very ambitious with sports-car offerings hopefully being brought down to 0.30 and sedans (GLC and 626) in the 0.35 class.''

Mazda already has some vehicles that are industry leaders in the CD category.

The Cosmo two-door hardtop, sold only in Japan, posts an impressive 0.32 while the rotary-engine RX-7 sports car records 0.34. To get the CD figures even lower, Toyo Kogyo is working on front and rear lamps so that air passes over them more easily. All side protrusions will eventually be eliminated except the outside rear-view mirror. The mirror will, however, be fully streamlined.

Further wind-tunnel work will have as goals high-speed stability for cars that are lighter in weight, minimum wind noise, minimum wiper-blade lifting at high speed, improved in-car ventilation, and aerodynamics that minimize the collection of road dirt and dust on the glass.

Mercedes-Benz of North America claims it is five years ahead of US carmakers.

The 1982-model 380SEC, a 4-passenger coupe, has a CD of 0.338 while the 380 SEL is rated at 0.36. The 380SL, however, is 0.41; while the 300D, 300SD, and 300TD (station wagon) are all rated at 0.42.