Hey gang- Driving around my beater Altima, & being a twin cam it's geared for performance (lol) instead of mpg.
So I'm figuring what I can do to streamline it, I noticed it has a gaping lower air dam / area which becomes a big parachute for drag.
Mocked up a template out of some coroplast, then used some leftover Celotex foam board out of the garage ($20 at lowes for a 4x8 ft sheet).
Shoved it into place, & voila'.
If I had a full sheet I would have used the back (black) side in an area of all black, but there was yellow print on what I had left so I'll use the silver side.
Cheap, easy & there's plenty of area in the upper grill to keep temps down.