[Coroner]

I just ran a decent load from Bryan to Detroit, back to Bryan to Webster, NY, over to Niagara Falls (To the Falls Park), then back to Bryan.

1160 miles all together with fuel averages running between 17.5 all the way upto 21.7 mpg. The winds were 10-15 as a tail side wind on the way there, and 5-15 head and side wind on the way back. Overall mpg totals came in at 20.35 for the trip. 300lbs of cargo and the wife. Most miles were driven at a speed of 58-60 mph using the cruise control.
I did jump up to 72 mph for about 80 miles on the way back using the turn pike.

Since, I run trips like this all the time, minus the wife, I can ESTIMATE the improved mileage at .5 mpg due to the bumper/fender gap being sealed. The biggest thing I noticed seemed to be the handling slightly improved when the big rig's pulled in front (Not as much shake and bake, as I refer to it). This trip I didn't get to used the coasting downhills as much because there were not as many hills steep enough to let the truck roll and keep up with traffic safely. I did coast on the ramps and where ever I thought I could, but not as much as I would have liked.

I like the gap improvement and will continue to monitor this as I improve it's securement to the truck. Every now and then, due to the bumps and vibrations, I have to gently push the hose back into place. It's not a big deal, and even if I forget to check it, it never sticks out as a problem or anything, it just won't be as effective IMO.

If I lived closer to a straight, flat smooth piece of highway or road, I could really test this better using a scan gauge and so forth, but for now, I will just have to work off of my best efforts to gather data, and run my cargo business as I go along.

I read in a magazine that one of the improvements being used in the big truck market to gain fuel mileage is sealing the bumper fender gap. Hmmm.......

When I can get the extra money, I will order a scan gauge and hopefully be able to nail down a scientific set of data. For now, I can only go by the pump calculations and onboard mpg indications, but don't have the luxury of returning to the same pump for re-fueling, (Same angle, etc.)

I'm doing my best to stay as accurate as I can with what I have to work with.