What is this? The black plastic pieces behind the grill.

[LoveThisTruck]

I removed mine, and it stays nice and cool... even with the Roe.

 

[SANCHOBA]

removed mine.......i believe they are there, as some stated to prevent lift of the front end at 150mph. if i run the "texas mile",i'll put them back in.

 

[HaroldD]

I played with aero some at Bonneville. I left mine in, but went one step further to tape over 1/2 of the grille and the scoop inlet in our hoods. I picked up 1+ MPH. Now, I didn't have enough runs with and without to say statistically that was it, but at high speeds, you want air going around the truck smoothly, not through it causing drag.

It is my understanding that those pieces actually deflect air from going in the engine bay. The air that does get in is forced around them and thus over the radiator. The reason for them, as I understand it, is it improves aerodynamics. If I recall correctly, it is similar to what the Nascar guys do to the fronts of thier cars. I think it was covered her on the forums before.

 

[Black1]

If you have a stock air box (with or without K&N filter element), I would leave them in.... If you have a aftermarket open element "Cold Air" Induction system, then I would take the pass side out (or both). Unless you are picky (like Carl and I), then I would leave them in or put a fine metal mesh in it's place (looks solid from the outside, but still lets air get through and is just as rigid as the plastic, for support).

I have my stock plastic pieces sitting around from my old truck.... if someone wants them, PM me and you can have them for the price of shipping. :dontknow: