[orbywan]

Originally Posted by Galane

I'm thinking what might work well for belly pans is to go from the front to just ahead of the bottom of the firewall, then on the next section curve it up to fit to the bottom of the firewall/floorpan area, cutting as needed to fit closely around stuff.

Then you'd have an outlet for engine compartment air through a slot that shapes and smooths the airflow, and as little as possible of that hot air getting between the floor and the rest of the belly pan.

There is so much going on in that area I'm not sure that's possible but I'll try to incorporate that into the original plan which is to just open up the pans in that area so the frontal air can get out.

One article I found when I looked this stuff up was a paper on the effect of various rear mud flap designs. A full width flap increased drag and reduced MPG but one with a gap in the middle increased MPG over no flap at all. Have to find the article to see what the numbers etc. are.

I'd love to see that Galane, let me know if you find the source again, OK?

What's the average MPG for semi trucks these days? I recall not long before the flat front tractors died out, some company built one with every aero trick they could come up with and squeezed 10 MPG out of it, which was bleeping excellent for any semi.

Yes, if you want to see designs better than today, frequently you just have to look and see what they did back in the old(er) days. We (me included) seem to be stuck in having to re-learn the past sometimes. Especially true with aerodynamics and politics. Thanks for the suggestions.