Darin Cosgrove is serious about MPG savings. How else, after all, would you explain the decision to give his car a boat tail for even better fuel economy? It's not a discreet spoiler-like attachment either. He slapped a huge-ass homemade boat tail that extends the rear in both a visually painful and uncomfortable-to-drive manner.
Cosgrove used a 1998 Pontiac Firefly as the canvas for his creation, adding what's effectively a snout on the car's rear end. While that eyesore on the back guarantees no one's going to get laid on that ride, it's not like you'll have girls lining up to take a spin on that econobox anyway. Probably, even back when it was brand new.
The frame of the tail was built using cardboard, dressed up with a black-painted aluminum skin to match it with the rest of the car. Looking to make the addition as minimally invasive to the vehicle as possible, he duct taped the entire thing. Yep, it's removable - thank God.
More importantly, the DIY boat tail managed to improve the Firefly's mileage by 15.1 percent when driving at 56 mph (there's a chart of the complete numbers on Darin's site). Along with a host of other hypermiling modifications, such as rear wheel skirts and a bellypan, he's managed to cut the vehicle's drag coefficient from 0.34 to 0.23, posting a total fuel economy of 64 mpg.
Construction of the entire rear panel took about 14 hours. The numbers are impressive enough (even though the looks are depressing) that Cosgrove is planning to build a more durable version for permanent placement. Seriously, everyone give yourselves a facepalm if this becomes the new eco-trend of 2010.