Some engines run more efficient in certain RPM ranges.

 

I get 28mpg cruising at 80 with 4.10s

 

Is that under nitrous too dimebag?! LOL jk man

 

What he said ^

The SHO engine makes less torque then my lawn mower under 2000 rpm; so get the thing turning higher rpm's and it starts making more power. Therefore it doesn't have to work as hard to maintain speed.

EDIT: The old V6 SHO engine I mean, the new one we know makes a buttload of tq.

 

I can get 26 ish cruise control for a 3 hour trip set at 70-75 mph...stock gears

And yes you can get better mpg at higher speeds. My mothers Cadi gets better mileage at 70 vs 60-65

 

i htink my top mileage was 23. but i do a lot of stop and go...so who the heck knows.

though i never care because i didn't buy this thinking i was going to get good gas mileage. im still hoping for 25 one day.

 

try to figure out at what speed your in your TQ band, without submitting to too much wind drag

 

Because of frontal air resistance and a car's high coefficient of drag extremeities, C/D, most cars do best in the higheast gear at 55-60 MPH. Air resistance trumps all other mileage considerations when you exceed 70 MPH. It is a huge inhibitor to efficiency at high speed and escalates exponentally as the speed goes up. It also is the limiter for those seeking top speed records. So why not go 35 mph? There is an optimum compromise between engine torque, gearing and other factors that eventually determine the speed where best gas mileage is attained. Normally that is around 55 - 60 MPH for the average American car.

 

OP, if you want the best mileage and speed is not really too much of an issue, then travel at 1600RPMs in 5th gear.

 

yea i dunno what that guy was talkin about shiftin at 2500, but thats a pretty terrible strategy. i get between 18-21 mpg city driving shifting between 1500-1800 rpms, while still gettin on it from time to time. the owners manual suggests that 55mph is probably your most optimum speed for fuel efficiency. now im not saying the people on here are lying about gettin over 25mpg at 70+, as i have seen this too. im just saying what the owners manual says. hell in my f150, i got my best hwy mileage ever cruising at 80 for ~2 hours.