My disclaimer is that this mileage improvement is determined from the stock calculator in the overhead console. I drove a set route on the highway a few weeks back with an essentially stock truck (AIS intake only). At a constant 60 mph, the calculator read after the end of a 30 mile round trip 18.5mpg. Turbo-Master Wastegate Controller and 203 degree thermostat were installed and the same trip was made at the same speed and the calculator read 20.3mpg. Tonight, after installing the DP-Tuner and switching to 80hp Econo mode, I got on the highway to make an identical run once again. The mileage sat steady around 25.9mpg for about 20 miles and for the remainder of the trip it slowly worked up to 26.7mpg!
Granted, the calculator is not going to give exactly what the hand-calculated result would be. However, seeing as all three runs were made identically and measured by the same device I would say it is fair to claim that DP-Tuner provided a more than substantial highway economy improvement! To go from 18.5mpg highway to 26.7mpg in a few short weeks with only $750 in parts is ridiculous. Thanks for doing your part.
A question about the transmission tuning ... the torque converter stays locked up during the downshift from 4-3 while I'm coasting down... is that intended?