Here are pictures of my new air dam.
This was made from a 3/4 inch box aluminum tube (14 gauge) bent into the shape shown. Once bent, I riveted lawn edging along the aluminum every 3 inches or so. It is screwed to the car with four screws untilizing stock holes that would normally attach the plastic belly pan to the fiber pan around 12 inches in from the nose.
It took about 2 hours to complete. This was amazing time considering it was 6 degrees F when I started and I did all the work outside. I had to stop repeatedly to warm my hands and warm the lawn edging at my heater.
The whole dam weighs very little. If I had to guess, I would say it is about 3 pounds or less.
I have not done any ABA testing. However, here is what I did for the few minutes of time I had;
I took my average mileage from yesterday (a full day of driving without the air dam), and compared it to a drive today around my area with the dam installed. Yesterday was 18 degrees and I averaged 47.1mpg. In 10 miles of driving today (after I warmed the car up), I averaged 49.3mpg. Now, bear in mind, yesterday's mileage was total mileage including the terrible MPG encountered with warm up. While todays mileage was recorded after the car was warmed up. Yesterday I drove 120 miles. So, the warm up MPG would have averaged in pretty well over those long miles. However, I would assume that I could have had maybe .5 to 1mpg better if I had warmed the car up yesterday before I reset the mileage trip odometer. So, realistically, the dam is probably giving me 1 to 1.5mpg increase (conservatively).
I will do some ABA testing sometime soon and report back.
The next mod I plan on doing is a rear diffuser. The rear of my car is totally open and really terrible from an aero perspective. So, I plan to make a light weight aluminum frame supporting light (maybe Coroplast) panels forming a diffuser.
Now, my question, since adding the air dam, I am limiting the amount of airflow under the car. I would assume this will minimize the affect of the diffuser. Is that correct? What I mean is, would the diffuser would do more with more air flow under the car? Since I am not after downforce, but reduced drag. Anyway, what are your thoughts?
Matt