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ChazInMT · 08-20-2012, 03:55 PM

I would modify some things here,
1st, that one picture shows the top front corner sticking above the back rear corner of your cab, that really will upset the air flow and almost render a large part of the cap worthless.
2nd, turn those corner supports that run front to back to 45°, this will ease the radius here and really help a lot, particularly in any kid of cross wind.
3rd, you need to raise the back end, your slope is much too aggressive. I understand that you think you want as small of a rear area, and therefore a smaller "Low pressure" zone behind your truck. But it does not work that way. You need to follow the "Aero Template" to achieve the best result.

Here's a pic of yer type of truck with the template.

4th, see if you cant put in some sort of support that bends the front to back top corners into a arching shape. Going straight from roof to top cap without a eased transition will really mess things up.

I know you've put a lot of work and thought into this already, and getting out to actually build something is awesome! Seriously good workmanship so far. But, you are making several errors that are going to really limit your results. Just a hunch, but your current design is only 30% of what is achievable. Will you see results? Yes. But if you make the 4 changes I suggest, I think you'll be in the 80% or better potential.

I have "photoshoped" some things onto your picture to illustrate what I mean here.

I really think if you're going to take the time to fiberglass this, you'd want it to be as good as possible. Also my suggestion #3 gives you a lot more usable space under the cap and improves the mpg result ta boot.

08-20-2012, 03:55 PM	#15 (permalink)
ChazInMT Aero Deshi Join Date: Jan 2010 Location: Vero Beach, FL Posts: 1,065 MagMetalCivic - '04 Honda Civic Sedan EX Last 3: 34.25 mpg (US) Thanks: 430 Thanked 669 Times in 358 Posts	I would modify some things here, 1st, that one picture shows the top front corner sticking above the back rear corner of your cab, that really will upset the air flow and almost render a large part of the cap worthless. 2nd, turn those corner supports that run front to back to 45°, this will ease the radius here and really help a lot, particularly in any kid of cross wind. 3rd, you need to raise the back end, your slope is much too aggressive. I understand that you think you want as small of a rear area, and therefore a smaller "Low pressure" zone behind your truck. But it does not work that way. You need to follow the "Aero Template" to achieve the best result. Here's a pic of yer type of truck with the template. 4th, see if you cant put in some sort of support that bends the front to back top corners into a arching shape. Going straight from roof to top cap without a eased transition will really mess things up. I know you've put a lot of work and thought into this already, and getting out to actually build something is awesome! Seriously good workmanship so far. But, you are making several errors that are going to really limit your results. Just a hunch, but your current design is only 30% of what is achievable. Will you see results? Yes. But if you make the 4 changes I suggest, I think you'll be in the 80% or better potential. I have "photoshoped" some things onto your picture to illustrate what I mean here. I really think if you're going to take the time to fiberglass this, you'd want it to be as good as possible. Also my suggestion #3 gives you a lot more usable space under the cap and improves the mpg result ta boot. Last edited by ChazInMT; 08-20-2012 at 04:13 PM..