Volkswagen’s quest for efficiency began well before lawmakers started linking emissions to fines. It sold several fuel-sipping, Formel E-badged models during the 1980s, and its research and development department took fuel economy to the next level by building a prototype named Öko-Polo designed to use only three liters of diesel per 100 kilometers, which represents about 78.4 mpg. One surviving prototype lives in New Hampshire.
Visually, little set the Öko-Polo apart from the regular-production variant of the second-generation Polo it was based on. It gained rainbow-colored stripes on both sides, and a roof-mounted spoiler borrowed from the Formel E, but nothing about these add-ons revealed the presence of a cutting-edge powertrain under the hood.
Power for the Öko-Polo came from a supercharged, direct-injected two-cylinder diesel engine with a displacement of 858 cubic centimeters. It made 40 horsepower, according to enthusiast website Polo Driver, and it gave the Öko-Polo a top speed of about 85 mph. Power was sent to the front wheels via a five-speed semi-automatic transmission; drivers still had to shift, but an electronic switch in the gear knob activated the clutch.
Even with 40 horsepower, a rounding error in Hemi-speak, the Öko-Polo wasn’t as underpowered as it sounds because it was very light. Its engine was loud, however, so thick layers of sound-deadening material kept decibels in check in the cabin. In hindsight, everything came together beautifully, and the prototype exceeded expectations. It averaged 138 miles per