in utah, most of the interstates are wide open with at least 75 mph speed limits. I am wondering what the new 6.7's are getting going 80 mph on level ground, anyone got an idea??

 

here in DFW it's not quite level ground, but I am getting about 17.5 at 80 mph sustained. 3.55 rear

 

I would do kart wheels if I got that good of mileage at that speed, I also ordered my truck with 3.31's. the 06 dodge I just sold would only get about 14.5 at that speed.

 

honestly, I've actually started driving a bit slower with this truck. at 65-70 I can get 20-ish mpg on my somewhat hilly commute (about 2/3 of it is 70mph limit with 1/3 at 60mph). that means moving from the fast lane to the slow lane, but it only adds a few minutes to my drive and stands to save me about 8 gallons per month. $20-25 per month savings is nothing to shake a stick at

 

That's pretty impressive mileage for that speed considering the amount of drag that these trucks have. I'm just curious what the same truck with 3.31's would get at that same speed?

As far as the Cummins only getting 14.5mpg, I'm shocked by that. My uncle swears that his 06 Megacab gets 21-23mpg even at 75-80mph! It had me considering going to a Cummins just for the mileage. But all along, I figured that he was lying just to make his truck sound more impressive than mine.

 

I double-checked my stats this morning and I got 17 mpg at 80mph, with hills. This is post-flash, though. It was less before I got the retune.

 

I, too, have slowed up a little. I like the better mileage. The few times I have ran 80 it looks like 18 mpg or so. At 70 it does 20 or more. No traffic tickets either.

 

With a 450 its not so pretty. The short trip I took my mileage went down to 10.5 mpg doing about 80-ish.

 

I have buddies in my neighborhood that claim the same thing from their dodges, it turns out they always trust the trip computer, on my '06 dodge it was always at least 4mpg higher than actual. the only way to accurately figure mileage is by hand calculating, I don't think under any condition my '06 dodge would get better than 16 or 17, I always hauled trailers so it was hard for me to get a good read, and when I wasn't hauling trailers I was running 80-85 on the highways.

my dad had an early '04 dodge specd just like my truck but those years has less emissions controls, I drove it on about a 200+ mile trip and IMO it would get about 10% better mileage than my '06 would have gotten. but still that was only about 16 mpg on the highway. the point I am making is I call BS on the mileage claims over 20 mpg, on any diesel except maybe the old trucks, I think you need to be averaging about 60 mph to get that kind of mileage and around here we just don't drive that slow. oh well I guess I will see in a couple weeks when my 2011 6.7 arrivers