Fuel Efficiency Older vs New

Did you post that correctly, 3.7 ?

 

3.7 is doing pretty good for me! I've seen weekly avgs of 3.2. short haul, lots of start stop, in a hurry and spend a few hrs unloading at 1450rpm

 

I’m local and get in a hurry a few times also, but my ISX15 (500)does 5.7 average and maybe 6 on a good day. How I wish I still had my old CAT, that one did 7 all day long regardless.

EDIT: So I guess it’s fair to say that I shouldn’t worry about my mpg under the circumstances.

 

That pto time adds up.

 

The older rig will use more fuel but the downtime lost revenue of the newer emission rigs will cost more than that .

one little Chinese sensor goes bad and your rig is sitting for days or weeks .

 

I've gotten better economy out of newer more powerful engines.

I don't how you all aren't.

DD15 505(iirc) got .6 better then the DD13 450 before that. ISX15 got .75 better then all isx 450s.

Mx13. Has yet to see a drop of oil loss in almost a year but I can't say economy on that one as it's a city truck.

My last job ended with a isx15 and I got 6.9 pulling 100k one way. It started with a cat getting about 5 pulling 100k one way.

As far as engine reliability goes. The mx is running circles around the other 3 combined. The only mechanical failure so far was the fuel pump. The motor has 650k.

The last isx15 I just drove got a new head at 175k. But it don't like the oil in it. It sounds like a tank.

Driver definitely makes a difference.
I could make a gallon of oil last 3 weeks when no one else drives the truck over the weekend. Otherwise, that gallon was gone in 2 days. They also burned 30 more gallons then me in a fillup. And would drain a full reservoir bottle of pto oil. Which would last me a week.

Some drivers just cost too much money to operate a truck.