Today I went and put the airdam on the truck. It is a very simple design, as you can see in the pics. By coincidence, the bottom wound up at the same level as the lowest part of the rims (the legal lowest limit in texas).
Pics:
Code:
Test without sheeting
1 2 3 (run #)
0 s 60 60 60
10 50 51 49
20 43 43 41
30 39 37 36
40 34
Code:
Test with sheeting
1 2 (run #)
0 s 60 60
10 53 54
20 46 47
30 40 40
40 33 35
50 29 30
60 25
I couldn't figure out how to use the coastdown spreadsheet from instructables, but the results are obvious. In the first run I would lose about 9 mph in the first 10 seconds, and with the sheeting, I would only lose about 7. The 3rd run was fudged by the GPS turning off in the middle of the run. Go figure.
I could also feel the difference in the foot and see it in the vacuum gauge. Cruising at 50 MPH (yeah, that low) I was able to use less throttle than normal (can't quantify that one, just feel) and saw more vacuum while cruising.
The engine fan kept coming on while at speed, so I wound up cutting out 6 holes in front of the grille. I also need to trim the edges of the pipe sticking out and (if I feel like it) spray paint it.
The front license plate is not mandated in my state, so does anyone think I could benefit from removing it? Aside from the sheeting laying flatter against the bumper, and being easier to fit around.
I'm looking forward to some results from this. I know, I know, I'm not being scientific about this. I removed the P/S belt in the same tank that I put an aero mod on. Oh well.