I made a change to my grill block. Although it was cleaner in appearance behind the grill, I decided to try a little more of a block. I added another piece to cover the middle opening, leaving an opening for the tranny cooler. The lower opening in the bumper is untouched.
I got an Ultragauge last October about the same time I made this change. I started paying close attention to a lot of gauges, including the temp. I noticed it warmed up a little quicker with the new grill block. Since I didn't hear any complaints about how it looked, I decided to move the upper block to the front as well. When I did this, I noticed that I got to full operating temp about a minute sooner on my commute. I can only deduce that there was enough flex in the coroplast to still let a lot of air through.
I don't do A-B-A testing, so I don't have specific numbers. The Ultragauge has been helping me improve my mileage, but I couldn't quite reach the 20mpg I was shooting for. Flipping the upper grill block to the front finally pushed me over the top. 20.5mpg on my last tank in spite of the colder temps and denser traffic this time of year:
http://ecomodder.com/forum/showthrea...mpg-15799.html
Mike