airfoil to improve 2008 F250 fuel economy
 

I did several searches in this forum but I must not be using the key words as I come up with no results. We have a 2008 F250 (6.4L diesel, Super Duty, Twin Turbos, long bed, extended cab, 4x4, off road package) we bought last August. Our fuel economy was around 15mpg with no load on freeways/backroads. Now, we are carrying a 2013 Hallmark Ute pop up camper (extra 2000#+ weight plus wind resistance). After putting on around 4000+ miles traveling from October to November throughout our beautiful SW on freeways, 4x4 roads, state/county roads, it is a dismal 11 or so mpg.

While we were stopped in Moab,UT, a guy with a bed full of antlers (sells to Chinese medicinal market) tells us he got at least 1 mpg better installing an air foil under front bumper on his 2008 for better air movement. It was standard on 2009 but Ford wouldn't recall to install. He said it was $100 from Ford but probably cheaper in aftermarket. I am having trouble finding any references except for towing trailers with airfoil mounted in trailer/5th wheeler. Or, maybe, I am missing any mentions because I am not that familiar with truck terminology. I am the female half of us and am way more computer literate than hubby which isn't saying much.

Can anyone help? Btw, I love our new to us truck. It is much safer than '99 Tacoma and gets us off road. I have also been researching grill/brush guards here and have had much better luck deciding one to get (Ranch Hand Legend). Thanks.

Hmmm, no one has heard of this or maybe I am not clear? Hubby tried to explain it best he could about what we are looking for. Anybody? Merry christmas.

Would you be referring to the black "wall-looking" piece hanging below the bumper in the pic below? If so, it's referred to as the bumper valance.

FYI- the weight of that ranch hand will probably effect your mileage as well, those bumpers are no joke!

http://i281.photobucket.com/albums/k...914_171309.jpg

Hi Judy, welcome to FTE!

Sorry about the lack of responses, often in a forum that moves as fast as this one things can get buried if nobody has a quick answer for the question.

Matt is correct here, the early build 2008 trucks had a much shorter valance than the later build trucks, and it was a common mod to install the valance from a later build truck to improve fuel economy. I don't think you'd see a full 1 MPG higher, but it would make a difference.

I don't think the weight would do much of anything for highway fuel economy, but the wind resistance would be significant. Pushing a brush guard through the wind takes fuel, and I believe you would completely negate any improvements with the longer valance with the installation of such a bumper. If fuel economy is a concern you should leave it stock. :-X22

Tires, tire air pressure, driving style, and weather are the biggest variables that you face in mpg on interstate driving.

Highway tires are 2-4 mpg better on long trips. Inflated at least 70psi.
Getting up to speed quickly and then working the throttle to minimize fuel burn on up hill climbs helps a lot.
On windy days, driving into a headwind will cost you at least 2 mpg.
The bumper valance my save you some fuel but only 1 mpg at most. Making a custom one that goes down to 2" above pavement may help more but it's a problem off road.
Your pop up trailer really has very little wind resistance and should not be a big factor.
Use the Motorcraft cetane booster in your fuel, it helps a little.
The 6.4 diesel benefits from a tuner if you want to go that route, removing the DPF which uses fuel to clean itself.

I bought the 2wd valance (shorter), moreso for the looks than anything else. :-X22

Stock one is in my original post, 2wd valance pic below:

http://i281.photobucket.com/albums/k...914_182632.jpg

Hmm, silly question but is there a longer valance I could install on my '99 SD?

How low does that one hang under the bumper compared to the 4x4 one?

I cracked my 4x4 one off road when the front end slammed into the ground. I would take it off completely but I need something to help hide the mounting points for my brush guard.

4wd valance = 7 1/2"
2wd valance = 4 1/4"

It's ugly without the valance, I snapped the pic below while changing mine out:

http://i281.photobucket.com/albums/k...914_173857.jpg

I liked the look without the valence before I put it back on when I painted my bumpers. The problem for me was that my Brush guard has 2 brackets through go through my current valence under the bumper and attach to the frame.

I just went and measured the brackets and the 4 1/2" valence would be perfect. I would only have to put a couple of 1/2" notches in the bottom instead of having to cut a T shaped hole through the middle of it.

Thanks for the info.

Thanks folks for all your helpful replies. I am the web person in the house; hubby never learned how as he was a refinery pipe fitter who is retired. I have taught him how to scroll and go back. So, we are handicapped in that I do not understand truck talk, he only posts through me.

That said, we may possibly get the valance. We aren't getting replacement bumper, just a brush guard with place for a winch eventually. We are getting brush guard for safety reasons. It seems people think they are playing some video car racing game and pull out in front of you even with 6550 pounds of truck/camper coming at them. Death wish? Also, we are up early, out late for photography opportunities which means critters are out. We have had some close calls. It have 36" tires so are high off the ground. The 4.5" one seems to be best as it wouldn't interfere with brush guard as much. We will get brush guard first. Thanks again and happy holidays.

I am guessing that the tall tires are a part of the problem with mpg...You have effectively changed the final drive ratio with dramaticallty changes towing ability and mileage. I am guessing your original tires were 32-33 inches tall....you speedometer is probably way off, also. I think the front air dam is the least part of the mpg issue....

yep, smaller street tread tires= better mpg, not as much lugging.

Tires came with the truck and are not stock. They were really expensive and practically brand new. That does make sense.

By the way, if the speedometer wasn't recalibrated for the larger tires, it is also throwing your MPG calulations off.

If the tires are 10% larger than stock, that means the truck is traveling 10% faster than the speedo says, and you are traveling 10% more miles than the odometer is counting. This also means you are actually getting 10% more miles per gallon than your calculations say.