So you've customized your car like the rest of your life: You've ordered the personalized plates. You've tinted the windows. You've slapped on the "I love animals . . . they're delicious" bumper sticker.
But how much would you modify your car if you knew you could get 100 miles per gallon?
We're guessing you wouldn't go as far as Darin Cosgrove has.
Cosgrove made enough eco-modifications to his matchbox-size 1998 Pontiac Firefly (sold in the U.S. as the Geo Metro), along with changes to his driving behavior, to achieve 99.7 mpg in winning the fifth annual Green Grand Prix in Watkins Glen, N.Y., in May 2009.
You might not be able to coax your car to 100 mpg, but there's actually a lot the rest of us can learn from what "green gearheads" like Cosgrove are trying.
Check out some of the changes Cosgrove made:
Eco-modifications
The grille block. "The engine compartment is an aerodynamically 'dirty' area of the car," in which air often gets sucked into the engine compartment instead of flowing fluidly around the car, says Cosgrove, the founder of the website EcoModder.com. (Eco-modding is slang for eco-modifying, or tinkering with cars to make them more environmentally friendly in some way.)That airflow is partly by design, of course: Air helps cool the engine. But "it actually makes a significant difference to cut that airflow down to just what's essential," Cosgrove says.
Darin Cosgrove's 1998 Pontiac Firefly
And the savings Cosgrove gets are noticeable: "We're talking about, depending on a speed, about a 3% to 5% percent increase in fuel economy."
Headlight gaps sealed. Similar to with the grille, Cosgrove sealed around his headlights to restrict air from entering. Again, it's not outlandish stuff, he says: "Most of the stuff that's on this list is not new; the automakers know how to do this stuff." In fact, Mercedes-Benz has advertised headlight sealing on some of its vehicles, Cosgrove says.
How much do such fixes increase fuel economy? "Most of these major changes, we're talking about a couple of percent" each, says Cosgrove. "With a couple of exceptions, there's no magic bullet to improving efficiency. It's more like magic buckshot. There's a whole bunch of things to do."
Smooth hubcaps. Smooth wheel covers mean less drag; there's a reason many hybrids have them, says Cosgrove. "You can buy those in car parts stores."
Fender skirts. For his Firefly, Cosgrove fashioned plastic, front and rear half-moon-shape "skirts" that fit over the top half of his wheel wells, very similar to what some big American land yachts from the 1950s and '60s had. (The front ones he fashioned are hinged to give the front wheels room to turn.) Some cars such as the old Honda Insight hybrid came with these on the rear wheels. Or they can be bought for a few vehicles.
"Again, it's a couple of percent" in fuel savings, Cosgrove says of this alteration.
"All we're trying to do is minimize the amount of turbulence that's being created by the vehicle's body," he says. "A typical vehicle is burning half of the fuel it uses just to move through the air at highway speeds."
Messing with the mirrors. Cosgrove removed his passenger-side mirror and folded back his driver's-side mirror during the highway portion of the competition route. So he could still see, he installed a convex rearview mirror for better visibility. "A lot of people will freak out: 'You took your mirror off. That's crazy!' Well, the passenger-side mirror was an option on this car!" Cosgrove says.
You can buy a convex mirror at an auto parts store. Cosgrove wouldn't recommend these strategies for someone who does a lot of lane-changing, however.
The spoiler. "One of the more labor-intensive modifications I did to the car," Cosgrove says, was making "a custom spoiler that improves the aerodynamics at the back of the car."
This isn't some store-bought spoiler. "You can't really buy drag-reducing spoilers on the aftermarket," he explains. The ones you see on cars actually reduce their fuel efficiency in the name of helping stability.
But Cosgrove's spoiler has another goal: It changes the shape of the car to make it more aerodynamic. By doing so, he found he achieved 5% fuel economy improvement at 55 mph, he says. But building your own specially shaped spoiler, he concedes, is advanced eco-modding.
How much did all these changes cost? "Not really a lot, because most of the stuff I did myself. So maybe a couple hundred bucks. Mostly it was my time," says Cosgrove.
The upshot of all these changes, however, is that his car "looks pretty weird. I've had people roll down their windows and point and say, 'What does that do?'"