B4U Task Force Admin
Grant did some testing and found there wasn't much of a difference in IAT's with or without a box.The last pic looks similar to my setup.
Inlet air temp is a lot cooler there than at the back top of the engine.
A 39°F difference in air intake temperature will result in a 7% drop in density, which equates to a 7% horsepower loss (25 horsepower on a 350 horsepower truck).
That's why GM put a hole in the radiator support for the OEM air intake. To take advantage of outside unheated air.
With the air filter is located down there I opened that hole a bit since the headlights block it somewhat. Hope to eventually build a box around the area to keep out underhood hot air. At speed I'm not sure it matters too much since there should be plenty of air coming thru the grill. And I'm going with cast manifolds which throw off less heat than headers.