OK, time to stop lurking and show what I'm doing.
First, my 07 Focus usually returns about 30 mpg in my commute. The current tank is going a LOT farther (412 miles on it with almost a quarter left) so my EOC'ing and other techniques I learned here are most definitely helping.
Anyway, here's the how the front end air dam is progressing.
The stock front end includes a smallish air dam and partial front end belly pan, as shown here:
Not bad, but it's not as far down as some of the chassis parts farther back, and being that bigger is ALWAYS better
(just kidding -- I know -- but easier to start a bit larger and trim than to add on later) I thought it could be improved.
I stopped by a local sign place and ordered a 6' x 2' piece of black coroplast. It's supposed to be available on Monday, so today I mocked up what I had in mind out of cardboard.
The left side was easier for me to reach, and taking a good look at it I thought I could also shield the exposed face of the front tires, too. Anyway, here's the left side.
From the front:
Under:
Detail at the fender where it curves up the tire:
From the back:
Not too bad. I took it off, flipped it over and made a mirror image template for the right side:
This went on:
With both sides on:
I just had to fill in the gap, pull it off carefully and wait for the coroplast:
And for next week:
There we have it. I'll likely screw the coroplast into the face of the existing air dam and under the fender lips (all plastic).
Hopefully I'll have enough left to play with grill blocking, too. Oh, and I'm going to have to figure out some way to put smooth covers over those fog lamp cutouts. Maybe some flexible plastic stuff (suggestions?)
I'll add on to the thread when I get the plastic and start cutting.