I'm patiently awaiting for the EPA fuel economy release. Do you guys/girls think that 36 mpg is possible from the Trailhawk 2.4L Tiger Shark with 9 speed auto? The same engine in the Dart is rated for 41 mpg and 31 mpg in the Cherokee. Am I asking for too much? The fuel economy will really determine whether or not we want to take a serious look into buying the Renegade.
No, I don't think you will get even remotely close.
First off, the 2.4L engine gets only 35 in the dart, which has a lower coefficient of drag than the renegade will, and less forntal area (part of what gets you the lower CD). So even in 2WD, it'll get worse mileage.
Second, fiat's claim is that it will get 32MPG in every trim level. So that's the probably the best you can expect for trailhawk as it is the most MPG unfriendly arrangement of the vehicle. I would be skeptical of that except that going form the dart, you are adding 3 more gears.
Third, worse rolling resistance. The dart can use low rolling resistance economy tires. AT tires are not as efficient. If I remember my rumors correctly, from the sounds of it they are trying to source what may be a renegade specific tire from falken. Allpar claims the falken wildpeak may be used on the trailhawk, so that special request may just be for sizing rather than a lower rolling resistance AT tire, but it could be they are looking for a lower rolling resistance AT tire, which would help.
Fourth, 4wd. I don't care what they disconnect, you are wither driving all four wheels, or you have some rotating mass presenting parasitic load on the drivetrain or the unpowered set of wheels. Both will eat up some MPG.
For the US market, probably the best fuel economy is going to come from something like the latitude 2wd with the 1.4l engine. The longer front bumper will provide better aero, and you get the skinniest highway oriented tires from that trim level. Limited bumps up width, and trailhawk goes to AT, both of which increase rolling resistance all else being equal.
Then of course there is the real world and how you drive it.