The Detroit Auto Show last month marked the debut of the a car with the lowest coefficient of drag of any production car--just 0.23.

That car was the Mercedes-Benz CLA, a small sport sedan powered by a gasoline engine. Efficiency figures haven't yet been released, but we can imagine it being quite frugal at highway speeds.

If you've ever doubted the benefits of aerodynamics, then another German sedan from an earlier era demonstrates them pretty effectively.

Jalopnik uncovered pictures of this 1981 Alpina BMW, built for a Shell Kilometer Marathon.

Alpina is best known for its tuning work on regular BMWs, turning them into luxurious, high-performance sedans, with little heed paid to fuel efficiency.

The Shell vehicle was different, though. Based on a contemporary E21-generation BMW 318i, the normally boxy sedan had its styling transformed with a huge aero appendage at the front--complete with BMW kidney grille.

It's not the prettiest thing we've ever seen, but there's no doubt it was effective--the Alpina 318i managed to win its class with a startling 88 miles per gallon--breaking the 100 mpg mark, in imperial gallons.

Jalopnik speculates that the engine may have been detuned, but the rest of the car looks standard--there are no wheel spats, aerodynamic hubcaps or even lower ride heights here.

One wonders what might have been possible with a boat-tail appendage, too--as any aeromodder knows, the air coming off the car is as important as the air hitting it.

There's no chance that new Mercedes will reach the heady heights of 88 mpg, even if it's offered with a diesel engine. But as the Alpina shows, good aerodynamics can make a heck of a difference...


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