After the air dam failing to gain mileage, I decided to go another route while I ponder the air dam some more.
I went to Home Depot, bought some 7$ flashing and then made a cardboard template. Using the license plate bracket and some leftover aluminum angle, I fabbed up some quick mounting brackets. I also put some angle inside the bottom grill opening to hold the bottom of the flashing in. Once the cardboard template fit, I traced it onto the flashing. I then used some self tapping screws to hold the flashing to the brackets.
Here is the pic I took.
Coolant temp stayed right at 195-200*, which is normal. I'll be sure to watch it as the weather gets warmer.
After ABA testing tonight at 50 mph, I got an increase of 1.7% one way and 2.8% increase the other way. Average gain was
2.2%. That is about 1 mpg at 40 mpg. Hopefully the net gain will be higher the faster the car goes. I am out of time to test until next weekend though.
It will take a few miles (4,000) to pay off, but I'll take the gain! I am going to paint it black when I get a minute so it doesn't stick out as much.