Originally Posted by mikennrg
Aerodynamics will have a bigger effect on highway MPG than any other mods you can do. Things like bed covers, mirror deletes, blocking off more grill, aero under trays, reducing ride height, reducing wheel well gap are all drops of rain. But many drops of rain can result in a puddle.
Guys are noticing MPG increases from the Diablo and Bullydog tuner. I think the added power makes it easier for the truck to stay in MDS mode. Eliminating the clutch driven fan while adding a 180 thermostat then setting the e fan temp to 200 degrees can help on the highway. If you're not running A/C the fan will never come on while moving.
Are the tuners voiding the warranty though?
Yea I saw the diablo tuner on AA, unless it was increasing the mpg by 7-10 on the highway, i can't see spending $600.
Yea i've heard about blocking the air flowing through the grill, wouldn't you need a hood to have vents in it at that point so the engine cavity doesn't get too hot?