economy for my gmc's toolboxes

[jen6238]

Hi to everyone, I hope your vehicles are getting good milage. I've been wondering about making up and putting a couple of aluminum (maybe plastic or thin fiberglass) contoured air dams around the square fronts of my weatherguard side mount toolboxes. I mean the big flat areas can't help the airflow, right? Should I consider the rear of the toolboxes also, probably. Has anyone here done something like this? Do they sell them premade anywhere?

[Daox]

Hello and welcome to the site.

Do you think you could get pictures that represent your problem and/or what you are thinking about doing?

[MetroMPG]

Something like this?

[jen6238]

My boxes kind of stickout more and I have this (lightweight) aluminum ladder rack. I'll try to post pics later, going to work now.

[jen6238]

can you see these pictures good enough? any thoughts?

[gascort]

couldn't hurt. I like your idea in the picture, but I think you'd be better off if you could get it to come all the way to the cab - probably lots of air running right against the window that you could smoothen out, plus if you don't get all the way against it, your air deflector could act as a parachute and hurt drag, or worse, rip off!
Welcome to ecomodder!
Any other mods planned?

[jen6238]

yeah that's an interesting thot maybe between the boxes and cab might do more. I was going kinda for what was looking good and smoothing the airflow.
let me think. oh and I am considering the tire cover smoothing and underneath smoothing. Try to help reduce airflow turbulence some.

[jen6238]

pix of my mod. I know it's not much but that bothered me every time i looked in the side mirror. A big flat windbreak stealin' gas!!!!! Grrrrr. Anyway this is what i did and it is creating conversation about mileage. Most of the comments are positive. I walk and ride my bicycle (an old racer) when i'm not working so i make up for my gmc just a little......

[stanz]

Not sure that's gonna help much, I would guess you create a vast amount of turbulence between the cab and the box. I have the EXACT same setup on my F150.

If you want to really improve the flow you need to create a transition fairing from the cab to the rear like on the big rigs. It should attach to the cab and taper to the rear. If you don't want to drill into the cab, mount it to your boxes and use foam to filled the gap to the cab.

Not rigid foam, flexible foam, like you use to install window A/C units. They used to sell foam pieces to go between caps and cabs back in the day. I dunno if they still sell them. The cab and bed of your pickup flex at different rates so the link can't be rigid.

I think the diamond plate finish may actually improve the flow of air over the boxes. I recall the "sharkskin" swim suits from a few years ago that weren't smooth. The ridges created a laminar flow with less drag than a smooth suit.

[zjrog]

Not that its any help, for my worktruck, I've tried all manner of adjusting me, the driver. I drive a 2008 Dodge 3500 4 door 1 ton service body truck with duals, and it is loaded with equipment and tools and parts, and often an ATV with fuel in the bed. I've seen a low of 10.5 MPG, but can never get it above 12.3. And its not mine to mess with but I wonder how some sort of fairings on the sides to blend flow from cab to box would improve mileage. Now granted, this isn't a highway truck (well, not much) and it spends a lot of time at 45 MPH and under in the desert. But even on the highway, 12.3 isn't great.

I'm really curious to see what sort of ideas the collective can come up with for you.