While windtunnels have long been employed in aerospace and all forms of race engineering, we’re likely to see them employed more frequently in future in the quest for improved fuel efficiency from our automobiles. Ecomodder.com’s Darin Cosgrove recently added this 1.37 tailpiece to his Pontiac Firefly to improve its drag coefficient from 0.34 to 0.23 and its fuel efficiency by 15.1 percent at 90kmh (56mph).

The 15 percent improvement is just from the tail, and was comprehensively proven with multiple bi-directional averaged runs at exactly 90kmh on a straight and level road, with no other traffic. The tail was removed and reinstalled during the test so the ‘A-B-A’ comparisons could be made in identical conditions.

The moral of the story is that it’s just as important to leave the air undisturbed as it is to slice through it effectively and one wonders just what shape our cars (and trucks) will be a few decades from now given the remarkable results of this homemade fuel extender.