Effects Of Air Dam (Ford F350 pickup)
 

Well, I finally got my air dam testing done. Six fill-ups over 2200 miles. thrre with air dam vs three without air dam.

Without air dam: 26.34 MPG
With air dam: 27.00 MPG

That equates to $1.72 less per fillup at local prices.

Congratulations !

How much does your 'fastback' contribute ?


P.S. Nice Road Trucker ...clever play on 'Ice road trucker "

(thumbsup)

The "fastback" is worth +3.0 MPG over an open bed.

I don't think it is optimum yet. I have talked to Phil (Aerohead) about a replacement - more usable and better at keeping flow on the surface.

I use the "nice road trucker" thing on five different boards and .CD is the first person to pick up on it.

Three miles per gallon ?
That's incredible !

I mean if you had a car that got fifty miles per gallon and noticed a +3 MPG improvement, I'd be impressed ..... but you are starting out with a truck that gets less than half that.
That is a huge change in fuel economy !



No one cought the Nice/ICE road trucker caption ?? NAH ...surely not.
I caught it and I haven't even seen the show ! I think everyone gets it , but they just don't mention it.
Again .. clever play on the name there.

Dave, your mirrors fold back don't they ?

When you are not pulling a trailer, I'm sure you would see a very noticable change in FE if you pulled them back.

( But then you knew that .
I was just wondering if you actually do it though. )

I searched around until I found a picture of your airdam..
I'm pretty sure that I've never seen one with that kind of frontal coverage.
I don't know very much about aero mods, but looking at that airdam,
I would have guessed that it would have been more effective.
A gain of 0.66 MPG is ok, but it just seems logical that it would have been greater.

So, I have to ask.. How draggy does your stock underbody look?

Thanks,
Rich

air dam
 

I think your headin' for the Guinness Book! 27-mpg 1-ton!!! I like it !!!!!!!!!!!!!!!

Yes, my mirrors fold back but I never run that way because I am blind as a bat to the rear without them. My bed fairing is completely opaque.

I have considered going to “paddle” mirrors if I can supplement them with a rear view CCTV. This may be what I do after I redesign the bed fairing.

The bed fairing was indeed huge. I got there in two steps. First, I documented the open bed MPG, then installed a hard flat tonneau. Testing indicated a 1.5 MPG improvement. Then I whipped up my “fastback” fairing for a pickup show. It improved another 1.5 MPG. I then removed the fairing and ran open bed (tailgate up) for a couple weeks and – sho’ ‘nuff! – my MPG dropped off 3 MPG and when I restored the fair the MPG jumped back up 3 MPG. So I am real solid on the efficacy of a fastback bed cover.

The big drawback of the crude bed cover is that it limits my utility. My summer plan is a new and improved version (10-11 degree slope) with simple wooden bows holding up a custom made snap-on cover, kinda like a boat cover. This cover could be either easily “peeled back” or removed to accommodate bulky bed loads. I don’t know if the improved bed fairing will improve MPG or not but if not I’ll know I have pumped that particular well dry.


When we ran the thread with the graduate thesis from the naval officer his FEA work indicated that side skirts would make the air dam even more effective. I have a pair of running boards that I removed from the truck a few years back (when I slammed it). If I modify these running boards into faired-in side skirts I’d look for another 0.3 or 0.4 MPG over just the air dam. I have some more rip-stop conveyor belt so I can hog them close to the ground with no worries about dragging. If I can realize an improvement of 0.3 MPG that will mean a 1 MPG (4%) improvement from managing the air flow beneath the truck. The bottom of the truck is very rough and has a lot of hot surfaces.

Wait til I put another gear on this truck!

Big Dave,

What made the most difference in your mpg increase? I have a 2008 Ram 150 with a 5.7 hemi and would love to see the results you are seeing.

Any advice would be greatly appreciated.

Glen,

glad to see this thread re-surface. Dave is a big inspiration to me; he has a vehicle that most people accept as a fuel economy lost cause, and done something about it while keeping it usable as a big truck. I point lots of truck guys to his results.