Fuel MPG in the 6.0 engine?

Cowpie · May 22, 2015

Just got home tonight after trip. 1243 total miles. fairly flat to rolling hills going to St. Louis then Memphis, then highway 63 back north to home thru winding, hilly stretches of Arkansas, Missouri, and Iowa, most of it two lane road. Fair amount of driving in downtown St. Louis and Memphis. 5-10 mph offset tail wind going down, 5-10 mph head wind back up. Lots of small towns, stop lights, traffic, slow downs / speed ups due to agriculture equipment moving, etc on trip back home. MPG for the entire 1243 mile trip came in at 16.7 average on 87 octane E10 only, various brands. Hand calculated each fill up and DIC was surprisingly close to hand calculated mpg. No need for me to hand calculate any more.

Edited May 22, 2015 by Cowpie

fjtort2 · May 22, 2015

Wish I could get 15mpg or better with my 6.0... Saw 13.2 once on the highway.

pcf · May 28, 2015

I've been running E85 lately. Off the line there's not much improvement, it seems like the acceleration at 40+ is a bit better. Mileage has 9 unloaded and as low as 6 while towing. Cost wise it's been a wash. The even more frequent visits to the pump are the worse part of E85.

BigKahuna · May 31, 2015

Just turned 1000 miles on mine and lifetime average reads 13.2mpg, mostly highway with some loads in the bed. Best round trip so far was today's, 14.9mpg according to the dash, 150 miles. The dash seems to be reading a .1-.4 low, so that's a good thing. Not thrilled with the MPG's but not disappointed either. My '12 Ram 3500 (cummins) was no better on fuel than this so far.

Cowpie · May 31, 2015

There are so many variables that can fluctuate mpg numbers, one just has to see how it all plays out in their area for what they do and see if they can live with it. I figure, based on what I have read, that I am just having some sort of dumb luck getting the mpg I am. But, I rarely deal with anything metro, just small town stuff, and rural two lane highways most of the time in rural Iowa. So I am not running very fast, even on the interstate I generally will not run over 65. Just don't feel the need to do so. Most of the two lane stuff is 60 mph in 55 speed zone kind of stuff. Rolling hills. Best 400 mile average of 17.5 mpg. Lifetime average of 14.4. For someone to get lifetime average mpg numbers in the 13-14 would be above normal from what i have read. I don't want to take mine anywhere near a dealership for fear that they flash the ECM and I lose some mpg. Do not have a Tim Allen belief that "If it ain't broke, you can probably still fix it".

Edited May 31, 2015 by Cowpie

Cosmic Charlie · May 31, 2015

My 2011 25 HD Lifetiem average for 126,000 miles is 13.8 --- no bs / 4 years - plowing / towing my boat / but 95 % highway

redneck ron · May 31, 2015

Added my second tank of gas this morning and calculated the mileage. 13.8mpg. And to my surprise, the DIC was showing......13.8mpg. I'm not used to those things being accurate.

Cowpie · June 1, 2015

I was somewhat surprised myself when I checked mine. The DIC is remarkably close to actual, and consistently so. I am comfortable now with just going with it and not worrying about hand calculation. My 2013 1500 wasn't that accurate. Yet one more thing that GM got right on the 2015 2500.

BigKahuna · June 2, 2015

My last 350 mile round trip I got 15.2 hand calc. This was with cruise set at 63mph, over 2 high mountain passes each way, some cargo in the box and pulling a light cargo trailer for a short bit. I'm happy. Lifetime avg is up to 13.8 now, and if I want to trust the truck's computer I had about a 550 mile tank range.

Keep your speeds down and good mileage is attainable.

Same trip my 14 1500/6.2 would have gotten around 19 on premium gas, so there's not a big difference.

Edited June 2, 2015 by Camstyn

Sixstroke · June 11, 2015

Just hit 1k miles. Lifetime average is 13.7 with 50/50 hwy and city.

I'm pretty pleased, I knew the 6.0 was a pig going in, but I've been able to drive somewhat aggressively, without worry.

Couple 100+mile trips with ~1200lbs in the bed, though no towing to date.

Can't wait to see the numbers once she's broken in.

doingr8 · June 12, 2015

Around town: 12

Hwy: 15-16

Towing 12,000lb 36' fifth wheel: 8

Not bad if you are easy on the gas pedal.

1time · June 12, 2015

15.7 over a 400 mile flat trip. It was holding between 17 or 18 until I got caught in a traffic jam.

wandern · June 12, 2015

15.7 over a 400 mile flat trip. It was holding between 17 or 18 until I got caught in a traffic jam.

What speed were you traveling?

1time · June 12, 2015

What speed were you traveling?

I was doing the speed limit except for the 3 major slow downs. It was 70 for most of the trip. Then varied between 55 and 35 changing every few miles for the last 80 miles or so. I have been a 6.5 hr trip but took 9.5 hrs. We were going to leave tomorrow morning. I'm leaving ahead of the rest of the group and heading back tonight. I shouldn't have much traffic but I usually got better mileage on the way here than on the way home in my 1500. I'll post my results.

1time · June 13, 2015

Okay. Home from OBX. Read out says 15.4 on the way home, which tends to be a bit conservative. It said I got 15.7 on the way down but I hand calculated when I filled up and it was 16.0 on the way down. The trip back was straight cruise control except about 20 mins of idle, brake, idle, brake through some roadwork.