Fuel Efficiency Older vs New

Buy the CAT. It won’t do better than 6 mpg on fuel, but it will be faaaaarrr more engine than a DD15. We have 1 DD15, and it isn’t terrible, but I would drive my CAT any day over a Detroit. If you want a Detroit, get a 12.7 Series 60. They are peppier than the 14 liter series 60, and the Jake’s are significantly better. They are great engines as well, but my bias is toward CAT

 

Doesn’t necessarily have to do with the engine, but if you’re looking for efficiency, you gotta have a drivetrain for the engine to be efficient. Doesn’t matter what engine it is. Just looking at fuel efficiency, the A26 Navistar does rather well with an Eaton Endurant overdrive transmission and 2.64 rears, low pro 22.5s. But if you have an A26 with an 18 speed and 4.11 gears, all the efficiency goes down the drain.

 

Fuel cost will be your biggest expense, whatever truck you buy. A slight difference in average mpg will make a big difference,.
There are guys that will spec a truck to drag elephants uphill and then claim they get better MPG than a fleet spec truck on flat ground. Don't believe it. I've seen guys with big motors for triple digit trucks claim they get better MPG than a fleet spec truck doing 65 mpg. Don't believe it. Don't buy more truck than you need. NOBODY is going to get better MPG speeding than they do at 60-65 MPG. Physics doesn't lie or wear a big belt buckle.

 

Just get the borg spec Cascadia like everyone else

400 or 450 DD15, 12 speed auto and 2.nothing gears…….

8 mpg so they say…….

 

3.55 with what transmission?

In a w9 and driven not with a lead foot assuming youre about 65+/- 2mph and hitting the right rpm band, i would expect 6 mpg (low/no idle) if the engine is running right.

Could be as bad as 3.5 mpg with a lead foot, wrong rpm/trans/high idle

 

8.5 with the D12 turned up over 2+ yr period with that pos 12 sp auto. Keeping it out of 12th on hills