well i have 25000 miles on the new 6nz and

the fuel mileage is about 5.20 mpg, not sure if it is because of the colder weather, i run dedicated with the same loads withing 1500 lbs on the same routes, i have the bully dog ceramic manifold and running the power pup on the economy setting, gonna fuel up and will post later my exact mileage, i wish i would have gotten the pdi manifold from haney and had him flash my ecm, i think im still gonna have him do it for me

 

ok just figured it out 5.277 mpg, what gives? any suggestions? its a 550 6nz 18 speed 3:55 rears 03 379 pulling a 53 reefer, i have the cruise governed at 65 mph, maybe going down to 60 would help. right now when im running 65 the rpms are at exactly 1400

 

What do you hold your speed down to?

 

yeah i run mine at 63 also, i haul the same loads to the same places, from mn to detroit twice a week so all that is consistant except for the wind and in the last 18,000 miles i am at exactly 5.700 mpg, i really wanna buy a manifold from kurt and have him tune my ecm, my buddy is thinking about buying my power pup from me so then i will have the money to do it, what are guys with the manifold and 6nz getting for mileage? i hear 6 plus but im not sure if they are real figures?