Aerodynamic Undertray?

2893 Views 5 Replies 5 Participants Last post by  GTyankee
Has anybody here attempted to build an actual under tray for aerodynamics under the truck? When putting my Magnaflow on a couple weeks ago I took a good long look under there and it looks like It would be relatively simple to fabricate something to cover most of the bottom.

To explain most of my mod history before this truck has been on sports cars and aerodynamics and trays are a huge deal on the track. But I know when I built an undertray for my STi it made a nice difference in gas mileage too on the highway. Seeing as these things are aerodynamic bricks I figure it should make an even nicer difference.
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i think it would make a difference, i had one on my evo an it gave me like 2 more mpg id say try it if it works good deal, i wish they sold em for these it would prolly make cleaning under the truck after off roading easier too
You could give it a try, but with the height of these vehicles you would end up with a lot of reverberating drag under the vehicle. A better bet would be to lower the ride and put on a front bumper cover to deflect most of the air around the side. You are driving a 5600lb brick (a bluff-type body), aerodynamics are almost unheard of on these things because they're not designed to drive at the speeds that major aerodynamic effects would kick in; ok, well, having my truck up to 155mph definately feels like you're a brick in a wind tunnel.

The underbody drag is negligable compared to the bluff face that these trucks present; you're pushing a massive wall of air which most goes over and to the sides, and with the front airdams a very small amount goes underneath. The biggest source of drag is the cab/bed low pressure roll and tailgate low pressure roll, so if you could negate these then you'd be looking at improving the aerodynamics drastically and would see better results compared to an underbody tray. But, I won't tell anyone not to give it a try and see what the results are, because imperical evidence beats theoretical any day of the week.
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Interesting. Well I will see if I can get the time to build one in the next month or so and let you know what I find. I built a limited tray on my 2002 Jeep Grand Cherokee that was lifted and it made a difference there as well, but I understand what you are saying too. Any gains though will be made without too much work so it's worth a shot.
I was always interested in doing this as well, it's gotta help a little, especally at highway speeds. Another big benefit would be that it keeps the underside clean of dirt and salt from these north east winters . Let us know how you make out with this, I would love to see pics and maybe plans to make one of my own.
On my first vehicles, late '40s & early 50's, many had a cover under the engine compartment. Everyone took them off once or twice before leaving them off, we also took the Fender Skirts off, too much hassle when we had a flat

I wonder how much the SOUND would be increased in the cab with a cover under our Rams
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