About a year-and-a-half ago I took a little cross-country trip to visit the folks back east. Beforehand, I decided to use the upcoming opportunity to test a hypothesis for aerodynamics affecting fuel mileage on the ’07 Dodge truck. Lifted pickups are the worst for fuel mileage, but I managed to keep this one averaging around the stock MPG level (18) with a tune and some other minor-to-major mods including a built trans with a tighter torque converter.
But there’s not much you can do about the lift, or so it would seem. Higher basically equals more drag from an aerodynamic perspective. Then I got to thinking about the aerodynamics and envisioned an air dam extending down from the front bumper. The truck is a road machine intended for towing trailers and hauling stuff, almost never going off the pavement anyway, so this is doable.
The prototype I created did well on the trip, with only a couple of minor issues needing corrected before rebuilding it to final spec. The front braces made from aluminum snapped right off the first time I bumped something hard enough. Steve, if you’re listening, you probably already found those laying alongside your driveway a year ago last fall. They are now made of similarly-sized strips of black delrin, an engineering thermoplastic used in precision parts requiring stiffness and dimensional stability. The skin was glued to the frame before, mostly for expediency’s sake, but now it is fitted separately with screws enabling easier maintenance if it ever needs repaired or replaced. I also added a little finishing touch by flaring the bottom corners out a few inches to give it a more appealing, streamlined look.
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So after like 50 hours of work and around $200 worth of materials, was it worth it? To me – yes, absolutely! The biggest and unexpected benefit from it is noise reduction. Apparently alot of the interior noise developed at highway speed comes from turbulence created by air moving underneath. Can’t say exactly how much without before/after decibel readings, but the cabin is noticeably quieter inside now. And it’s good for a solid +1 MPG. Lifted pickups with big tires are notoriously poor fuel mileage machines, so every little bit helps. It still needs the seam where it attaches finish smoothed and that whole bottom front plastic area coated to match.