[gumby79]

Seehttp://ecomodder.com/forum/showthrea...rty-35894.html
This was my experience with testing . Will be the best answer. A pic from the front highlighting what the manufacturer did would help. As you said tomarrow.
Most moddern cars use a Spat. A small 1-2 tire with mudd flap looking thing 1-2" vertically angled slightly to the outside 1/3 tire. This softens the angle of impact, and redirects the air to go around the front tire with the smallest protruding wake(hence they stop short of the edge of the tire). This reduces the increases of frontal aera to the smallest number with the maximum effect. At some point the increases in frontal area offset the improved side flow. Theas spats that I have seen (I freek out car sailsmen and start asking them aerodynamic questions wile looking for the patterns of what the new technology is hidden by bodywork) typically start about 2" rear of the red and finish about1.5-2" forward of the finder openings.

Coefficient of drag down, Aera up at equal percentages will net a zero change. Its about finding a balance. And that can only be found by mesuring . To improve accuracy add a vacuum gage so you know if your driving teckneek is consistent or if the results are skued. If posable drive 30mi prior to startingthis test session to insure everything is constantly warmed up.