13 or so around town and 17-18 on a trip with an 08 4.7.

 

i'm gettin about 14.5 around town 17 highway (70+ mph). 3.7 w/ e-fan, intake, cat-back

 

1 get 14-15 in town, and if I drive 65 mph I've gotten 21.9.... only a few times tho...

 

I crack 20 on the highway @75.

 

I've been setting 16-17 city with mine as long as I'm easy pulling out. Best I've ever gotten highway has been 21. The milage seems to start to suffer some at speeds over 65-70mph where I generally won't seem over 20 at speeds above that.

 

is this with the 4.7 or the 3.7?