Dash pic after we left Lordsburg, NM. While we were still climbing grade to the continental divide 20 miles east of Lordsburg at 4,580 ft we had a tail wind. We often seen 13+ MPG on level ground and easily seen 15+ MPG going down slight grades we usually seen 10 to 11 mpg climbing slight grades. By slight I mean no more then one (1) degree. We seen even higher MPG figures after we crossed the divide on our way to Deming, NM (see second pic). At Deming the wind switched around to the SE and trashed our MPG's to Las Cruces, NM.
1: Filled up in Las Cruces, NM for the trip.
2: Filled up in Safford, AZ 22.081 gallons for 263.9 miles. It was actually only 205.2 miles to the park so 58.7 miles of this composite trip mileage was driving the truck without the trailer or 22.2%. Composite average 11.951 mpg.
3: Drove to Las Cruces by a slightly different route to I-10 in Lordsburg for a total of 202.5 miles using 17.93 gallons of gas for a composite average of 11.461 mpg. Only 6 miles of this leg was with the truck unhooked from the trailer or 2.9%.
4: Total miles 466.4 miles on 40.011 gallons of gas for a composite average of 11.656794 mpg. Total miles unhooked 64.7 miles or 13.8%.
Synopsis: My trailer towing mods were a qualified success. On level ground with no or little wind I seen 13+ MPG easily. Side winds, and up grade performance were usually impacted negatively with MPG figures as low as 8 MPG climbing grades. The truck's greater Peak HP and Torque output made traveling easier then my last tow vehicle which was a 270 HP 2011 model 4 Runner.
Conclusions are that a gap filler is in order to mitigate some of the crosswind effects as well as stopping the air on the sides of the truck from hitting the exposed frontal side areas of the trailer. I think I have a way to do this without using any intrusive fasteners on the trailer.
A two foot boat tail would be nice addition to this also. A faring to clean up the air around the AC unit on the roof would be a good idea also.
We are planning a trip to the Florida Keys in February 2016 which will be a plus 2,000 mile trip possibly as much as 4,400 miles in round trip trailer towing. Some kind of mods to improve the aerodynamics of this vehicle combination even further would be a good idea before this mega trip.
John Gilkison June 22nd, 2015