My F250HD Air Dam

[Jetta90GL]

After getting tired of getting 10 to 13 MPG consistently after every thing I've tried to get better MPG, I decided to put this together over the weekend. I haven't done any fill ups to check if it helps any, but it does seem noticeable that it takes less power to accelerate at higher speeds. I tried to make it high enough to miss stuff laying in the road, and strong enough to survive some unpacked snow. The hole in the middle is going to be an automated door for cooling once the grill is blocked. Enjoy the pics

[GasSavers_Mr_C]

I put a similar V style air dam on my old ford... and it was also strong enough to handle compact snow...



Seriously though, thats really impressive. What kind of metal did you build that out of? It looks like a good and tough design, although you might want to consider doing something that will let it bend back if it hits something hard (like snow) and then spring back, just so you don't wreck it... Not sure how doable that is. Now that I see your implementation I am thinking that I should try to build something that looks much like that but fits into my plow mount for summer use.

You have to be getting a mileage improvement from that, and it looks surprisingly good.

Have you done anything else to the truck to help improve mileage?

You should consider getting a "cold front" to block your grill. I have one for my f250 and it is quick, easy and looks pretty good, although with your attention to detail, you could probable make something that looks equally good for less $s.

-Mr_C

[bones33]

Go ahead and block the middle of the dam. Make the grille block adjustable to suit your cooling requirements - about 4sq in per 25 hp used. Highest air pressure as you might assume is in the middle of the grille so put your opening there to divert the maximum air around the vehicle.

[bones33]

Nice fab work by the way!

[theholycow]

Looks as good as a huge air plow could look. I wish I could do work like that!

I can't wait to hear the results.

One question: Why not remove the lift first?

[collegekid01]

wow that's a really big air dam... you should try blocking your grille too then you'd see some mpg boost

[Jetta90GL]

I made it out of aluminum "U" channel and angles. All of it is half inch wide except for the curved bottom edge, which is 3/8 "U" channel and I used a 1 inch angle on the frame that is in front of the oil pan. I used 1/4-20 bolts to connect the stronger parts together, and to the bumper. The rest I used aluminum pop-rivets, using 2 on each joint. I only needed to drill 2 holes in the bumper on each outer end by the tires. The other 4 use the license plate holes and a pair of holes on the back of the bumper.

I don't really have a lot of room between the air dam and the tires to allow for any sort of spring back action. One thought I was having was to make it so it could be adjusted higher for days when there is deep snow or, driving off road.

Right now I do have the center part blocked with some corroplast taped on, I still havent decided if I want an adjustable grill block or use the center square hole. I have used a cardboard grill block for the past 2 winters, and it does help by like 2 mpg. Although that just brings me back up to my summer MPG. I was thinking of making a grill block out of tinted plexiglass cut to fit the slots and also covers for the driving lights in the bumper. I think now with the dam, I will actually see the grill block do something good in the summer.

As far as i know the truck came from the factory with the lift. I can see taking the spring blocks out of the rear axle would be easy enough, but the front looks as low as it can go with out going with lighter duty springs. I only plan on keeping the truck for 2 to 3 more years, or until they finally come out with a 4 liter half ton diesel truck

I can't wait to see the results either, but I'm stuck traveling for work on weekdays while the truck sits in long term parking at the airport Thanks for all the comments, most people that seen it cant get past WTF is that! Then when I explain it i just get a lot of but air flows through the truck better with out it.

P.S.
I have my other modifications listed in my garage.

[theholycow]

Originally Posted by Jetta90GL

Then when I explain it i just get a lot of but air flows through the truck better with out it.

That may be a valid concern. At that height, with so much empty space under the truck, you may have greatly increased your frontal area even if you've slightly reduced your drag coefficient (which you may not have done).

Now, instead of a bunch of air flowing under, you'll have to plow the air out of the way and drag a vacuum. The air will come in under the sides, which could conceivably be better than turbulence around the front axle.

For a lifted truck, it may be better to put in a complete smooth belly pan/skid plate, and fairings for the axles. I don't know, but your experiment will definitely help add some data!

[Jetta90GL]

I could see that happening if the air dam was very close to the ground. I actually made it a couple inches higher than the lowest part of the front gear case. It is a little over 10 inches from the ground. I plan on covering the underside of the V shape of the air dam, Ive also thought about extending that area to under the front axle as sort of a belly pan.
I'm hoping the dam will take me up to the 15 mpg mark, so that it can be worth driving an old locomotive with a cow catcher.

[Jetta90GL]

Well my first fill up turned out to be 12.83 mpg. Not too much different from my past fills. I planned on the trip being mostly highway, but I forgot that there is a detour. So a lot of it was back roads with stop signs, curves and speed limits. Also the directions were wronggg and we got turned around in the city. On the highway my cruise was set for 70 mph and i had the AC on for the trip down but not the trip back. I haven't been very disciplined on hypermiling or just plain keeping my foot out of the gas, so 12.83 might not be the worst. I really need to block the grill..