Large Pickup Aerodynamic Mods

[aerohead]

There was some discussion of bigger truck fuel economy over at maxmpg.A couple of years back,Popular Science did a mpg comparison between a GM 3/4-ton diesel pickup and a Ford Taurus.I take issue with their methodology as they seemed to mix apples and oranges,however they did site some recommendations for fuel economy by Rich Taylor,Chief of GMC truck division.

As per Taylor's recommendations,the magazine's crew blocked some of the grille,fabricated a partial bellypan for the sides of the under-chassis,leaving the center exposed (presumably for cooling insurance),and installed a tonneau cover over the bed.

An internal memo pegged the gasoline truck at, I believe,17-mpg,the modified diesel,at 55-mph,returned about 26-mpg.

Members have discussed a gradual blocking of the grille and then monitoring temps.Good idea! As with GM,the Ford cooling system may be designed to deal with Death Valley,at the peak of summer,with all accessories on,at idle.I suspect,short of those conditions,one could safely block some of that grille with no ill effect.

If the chin spoiler is not as low as the lowest suspension member,an addition to the spoiler would block some air from the underside,giving some of the benefit of a bellypan.

The truck is heavy,but there's little you can economically do about that.

Around town,aero mods won't show up at the diesel pump. If you do a significant portion of highway travel,then the back of the truck is where your fuel is going.Anything you can do to clean up the wake will pay dividends.

[Big Dave]

All this is in line with what I have found.

[LUVMY02CREW]

Hey bigdave,

I checked out the pictures you listed above, but didn't see any pictures of what you have behind your front air dam. Does it have anything built behind it to maintain shape or does it maintain shape on its own?

I ask because I have a smaller piece, 9-10" wide and FREE, that I'm gonna give a go on the front of my bumper to smooth out where the tow hooks and license plate area are. Just wondering if mine did "give in" some without anything helping it out if it'll be worth it?????

[Big Dave]

Myair dam has a curve in it against the wind plus two flat aluminum plates to hold its shape. It holds its shape well at road speeds.

As for grille blocking, you can fearlessly block off the vertcal openings - they are 100% decorative. You could block 6 inches off either side of the horizontal opening as well and still get full air flow to the condensor, intercooler, radiator stack. My chin slot also gives air flow to the tranny cooler.