Hey guys I got a 2006 Cummins with 37" tires. I know they will hurt my mileage but I am only getting 400km out of a tank which seems very odd to me. I hear guys pushing 700km or more on a stock cummins so I don't know where to start here to improve my mileage. I bought an edge evo ht tuner for better mpg but no results any help?

 

Do your research on the forum this topic is all over! Keep rpms below 2k! Cruise 55-65 mph each truck has a different sweet spot. Easy recipe for better Mpg
1 - intake (BHAF or AFE dry filters
2 - exhaust ( ditch cat and stock muffler)
3- tune low smoke (EFI live is king for mpg and HP with smarty as a runner up)

Read the sigs and see what setup guys are running

 

an intake and exhaust are not really gonna help your MPG's. some guys get better millage with tuners and some dont get improvements. EFI live is what you should run on your truck. plus edge runs hotter. sometimes dirty sensors will decrease your millage, so clean those. your tires and lift are a killer when it comes to MPG's. are you comparing your truck to stock trucks or ones with similar set ups? does your truck smoke that much?

 

I've lost mpg's even going from 285-70-17 to it's "75" bigger brother.
Maybe a set of Yokohama 37's would help. Narrower and lighter than some.
I emailed a couple of EFI tuners and they couldn't honestly guarantee increased mpg,just better driveability.