ok my boss has a d max an he found out cummins gets better fuel mileage and now he wants to buy a 08. i have a 01 and i easy get 20 mpg. how good do yal get with your 6.7s with no performance mods?

 

Bone stock? He'll be lucky to average 17.5 on an all highway trip. Some get better, many get worse, but that is about the average. If he wants mileage he needs to lose the DPF and EGR.

 

I have an 07.5 6.7L, 2500 QC, SB.

My truck has 22000 miles on it and I average about 19 to 19.5 highway at 75. If I drop down to 65 to 70 the truck easily goes over 20mpg. All hand calculated. The truck is bone stock, including michelin tires, with the exception of an after market cold air intake. Honestly, I am not sure I can tell much of a mileage difference with the cold air intake...maybe, at most, an additional 0.5 mpg.

All of my highway driving is using the cruise.

The truck still has all the emissions stuff on it and most of my miles are highway.