Jump to content

6.6 Gas MPG

brendon444
 Share

Recommended Posts

SkidooSteve12 Enthusiast

SkidooSteve12

Posted
Posted

Seeing my truck in the parking lot next to other pickup trucks, I can see why the gas mileage isn't much better because it is so much taller and has a big front end that is pushing a lot of air and taking in a lot of air through the grill. And the stock tires on 20" wheels are huge compared to what we used to run on 2500HD trucks, so that eats up some MPG's and I think that's why some people are getting better MPG's than others. Here is a comparison between sizes and at the bottom what is available for the 2020 HD.

 

455262954_Tiresizes.jpg.884733604db0d0d495de8fdf7b44f0f3.jpg

 

 

 

Does anyone else use the aCar or Fuelly app? I have since I bought my truck and here are some screen shots of my info so far. I have noticed that the 2 highest MPG tanks were after I filled up at a different gas station than the cheapest place by me which is a Sam's Club gas station. I am going to have to test filling up at a Shell station and Marathon. We have a Wesco by us which sometimes is the cheapest price.

 

20191126.thumb.jpg.9e814079cbe28ba0381d058e3b4b872b.jpg

 

20191126b.thumb.jpg.6d5c8d8b77223a9b329170bebed5d775.jpg

 


 

  • Like 1
  • Replies 124
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

kenny_r
kenny_r

The one thing they got right though is putting the large fuel tanks on the 6.0 HD’s because I’d hate to fill up every 80 miles [emoji23]

i82much
i82much

have you ever heard of the “Internet?”

Cowpie
Cowpie

Yeah, I am really surprised that GM felt the need to depart from 4.10. It might be from a mpg mindset, but usually that doesn't play out as neat as the folks in cubicles think they will.   

Posted Images

SkidooSteve12 Enthusiast

SkidooSteve12

Posted
Posted

Had to start a new post to continue adding pictures.

 

This is a picture of my trip meter which hasn't been reset yet since the truck rolled off the assembly line. It had quite a bit of idling time when I was test driving it and testing how my trailers hooked up to it. It is right on par with saying 13.2 MPG and my aCar app saying overall MPG is 12.5 with the 0.7 MPG difference which is right about what I see the difference is with each tank of gas, varies between 0.4 and 0.8 so far.

 

IMG_20191125_171749.thumb.jpg.328ab3ed82449b5f2b36cd4ce095410a.jpg

 

 

Regarding the RPM's at cruising speeds, this is a pic of my RPM's with the cruise set at 55 mph on a flat road. And my 25 and 50 MPG best ratings. I never really thought about the engine using more gas if the engine is running below optimal RPM's. Even at 80 MPH my RPM's are just under 2000 I think in 6th gear.

 

IMG_20191125_171626.thumb.jpg.45c3a0409e43ae60188c8c0539ddecd5.jpg

 

IMG_20191125_171547.thumb.jpg.85986dc02c21d09f6b8dfc086ae4ca04.jpg

  • Like 1
Ray Pickle Enthusiast

Ray Pickle

Posted
Posted

Shotgun z71, based on your post regarding your best for 25 mi 50 mi and 400 you are getting good mpg. Those 2 mi. commutes are killing your average as Iam sure you know! Cold engine rich fuel mixtures then early shutdown. I think 12 or 13 mpg on short commutes is the best your going to get

texasnavy05 Enthusiast

texasnavy05

Posted
Posted
12 hours ago, SkidooSteve12 said:

Seeing my truck in the parking lot next to other pickup trucks, I can see why the gas mileage isn't much better because it is so much taller and has a big front end that is pushing a lot of air and taking in a lot of air through the grill. And the stock tires on 20" wheels are huge compared to what we used to run on 2500HD trucks, so that eats up some MPG's and I think that's why some people are getting better MPG's than others. Here is a comparison between sizes and at the bottom what is available for the 2020 HD.

 

 

 

 

 

Does anyone else use the aCar or Fuelly app? I have since I bought my truck and here are some screen shots of my info so far. I have noticed that the 2 highest MPG tanks were after I filled up at a different gas station than the cheapest place by me which is a Sam's Club gas station. I am going to have to test filling up at a Shell station and Marathon. We have a Wesco by us which sometimes is the cheapest price.

 

 

 

 

 


 

 

12 hours ago, SkidooSteve12 said:

Had to start a new post to continue adding pictures.

 

This is a picture of my trip meter which hasn't been reset yet since the truck rolled off the assembly line. It had quite a bit of idling time when I was test driving it and testing how my trailers hooked up to it. It is right on par with saying 13.2 MPG and my aCar app saying overall MPG is 12.5 with the 0.7 MPG difference which is right about what I see the difference is with each tank of gas, varies between 0.4 and 0.8 so far.

 

 

 

 

Regarding the RPM's at cruising speeds, this is a pic of my RPM's with the cruise set at 55 mph on a flat road. And my 25 and 50 MPG best ratings. I never really thought about the engine using more gas if the engine is running below optimal RPM's. Even at 80 MPH my RPM's are just under 2000 I think in 6th gear.

 

 

 

Great write up.  I'm going to start using fuelly.  

 

I wonder what the difference is between the trip mpg and hand calculated mileage?  Does the DIC exclude fuel burned while idling?  My DIC is also consistently higher than hand calculated.

SkidooSteve12 Enthusiast

SkidooSteve12

Posted
Posted
14 hours ago, texasnavy05 said:

Great write up.  I'm going to start using fuelly.  

 

I wonder what the difference is between the trip mpg and hand calculated mileage?  Does the DIC exclude fuel burned while idling?  My DIC is also consistently higher than hand calculated.

Thanks. I used Fuelly's website before when I had a 45 minute work commute one way. Before that I made a spreadsheet that I would fill out after each fill up. lol Yeah I like keeping those kind of stats. Engineering mind always going overboard LOL

 

Some say their DIC matches their hand calculated MPG, but most people will agree that it doesn't match up correctly. Not sure why.

Ray Pickle Enthusiast

Ray Pickle

Posted
Posted

Ok, just returned from first road trip. Cincy to Nashville and back 675 mi. Including a short amount of city driving, less than 20 mi., I hand calculated 16.2 mpg rainstorm on way down cut mileage noticeably according to DIC. It was showing 16.6 prior to rain during first 50 or 60 miles on trip down but dropped to 15.9 in subsequent 200 miles. Rained coming back for majority of drive as well. I think it cost me a solid 1 mpg. But pure speculation, educated guess!

  • Like 2
greatmizzou Enthusiast

greatmizzou

Posted
Posted

I got my computer to eek out 20.0 mpg on the dot for 50mpg average.    Interstate plus some county highway travel rolling hills. 
 

was suuuuper gentle on the accelerator, would take advantage of downslope and coast up hills as light as possible.   59mph looked like the sweet spot for highest mpg.

 

 

  • Like 2
SkidooSteve12 Enthusiast

SkidooSteve12

Posted
Posted
13 hours ago, greatmizzou said:

I got my computer to eek out 20.0 mpg on the dot for 50mpg average.    Interstate plus some county highway travel rolling hills. 
 

was suuuuper gentle on the accelerator, would take advantage of downslope and coast up hills as light as possible.   59mph looked like the sweet spot for highest mpg.

 

 

What size tires do you have?

ShotgunZ71 Senior Enthusiast

ShotgunZ71

Posted
Posted

Had another trip with the 5th wheel over the Thanksgiving holiday. Somehow, I averaged 8.0 mpg on the trip home. Usually is around 7.5 so far in various types of traffic and roads.

cmysstailights Enthusiast

cmysstailights

Posted
Posted

Dam, i average 6.5 towing tt 10k lbs on e85. Was hoping that motor would be doing atleast 9 or maybe 10. Really feel the new trucks need bigger gears.

Sent from my SM-G960U using Tapatalk

greatmizzou Enthusiast

greatmizzou

Posted
Posted
1 hour ago, SkidooSteve12 said:

What size tires do you have?

18" LT275/70 R18E
 

 

I had to really take it easy to get it that high,  people behind me if there were any would not have been happy lol.  
 

More realistic gentle driving is 15mpg average mixed highway use.   Straight highway probably 17mpg

magnum74 Enthusiast

magnum74

Posted
Posted

If they're able to add 1mpg to this truck with such noticeable size, power and capability increases they've done a phenomenal job in my book. The stats on the new 2500 make my 2016 look like a toy.

  • Like 2
ShotgunZ71 Senior Enthusiast

ShotgunZ71

Posted
Posted
6 hours ago, cmysstailights said:

Dam, i average 6.5 towing tt 10k lbs on e85. Was hoping that motor would be doing atleast 9 or maybe 10. Really feel the new trucks need bigger gears.

Sent from my SM-G960U using Tapatalk
 

My previous TT was 9500 lbs and I averaged 8.5 running 87 octane. If you're getting 6.5 running E85, I'd say that's pretty good. A lot has to do with terrain, speeds towing, etc. E85 is good for making power, but crap for getting good mileage. I believe @Cowpie  runs E85 almost all the time on his 6.0 and could be a better source for the power/mileage of E85.

cmysstailights Enthusiast

cmysstailights

Posted
Posted
My previous TT was 9500 lbs and I averaged 8.5 running 87 octane. If you're getting 6.5 running E85, I'd say that's pretty good. A lot has to do with terrain, speeds towing, etc. E85 is good for making power, but crap for getting good mileage. I believe [mention=122677]Cowpie[/mention]  runs E85 almost all the time on his 6.0 and could be a better source for the power/mileage of E85.
Towing in the mountains upstate ny. I have average 3mpg less than 87. Looking to go diesel now

Sent from my SM-G960U using Tapatalk

ShotgunZ71 Senior Enthusiast

ShotgunZ71

Posted
Posted
2 minutes ago, cmysstailights said:

Towing in the mountains upstate ny. I have average 3mpg less than 87. Looking to go diesel now

Sent from my SM-G960U using Tapatalk
 

I can see where that makes a big difference towing. If I were towing more in the mountains, I may have contemplated a diesel again. We tow the 5th about 10 times a year, with 9 of them non-mountains. Some rolling hills, but not too bad. With the gasser, you can let it churn (manually, if needed) in the 3-4k range and be fine in the hills. Sure, your mileage may be less, but you'll be able to maintain with traffic. How do you drive the truck normally? Short trips, mountians, etc? I have a lot of short trips, also, so the gasser was a perfect fit for my needs and uses. Also saved a little money in the process. I had a Duramax and really enjoyed it, but I didn't really work it all the time like they need these days. For where I go and what I do, the gasser does great.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,902
    Total Members
    8,960
    Most Online
    whenindoubtuseahammer
    Newest Member
    whenindoubtuseahammer
    Joined

  • Who's Online   2 Members, 0 Anonymous, 350 Guests (See full list)

  • Latest Articles

  • Posts

    • Chuck FB
      OCI, not when but why?

      By Chuck FB · Posted

      Its no wonder you've gravitated to the oil types and brands you have in later years after trying certain brands and one being a specialty oil or at least very hard to come by up here and the other would have been a commonly found oil of the era and the vastly different outcomes as a result to using the vehicles in question the same distance for an OCI . It shows what marketing hype can do without actually having the product to back up the claims and that is no different now with the insane claims that are written on the side of a bottle of oil from some of the off the shelf oils.    What has surprised me and I was already finding this out before I bought my truck with the GDI engine, that this newer fancy technology that seemingly would suggest better fuel economy/emissions with this high pressure spray of fuel is not in reality kind at all to the engine or at least the oils life. Yet they insist on claiming long OCI with this technology just like they did with the port or similar type fuel injection systems when in reality its a step back in oil life to have a GDI system.    I think the mistake your making Grumpy is that your not sending your samples to Blackstone and getting the feel good glowing report that you can run it another 1000 or more miles and then send another sample where they say run it yet another 1000 miles and on and on it goes until your sending in something that looks a lot like road tar and then they may suggest you change your oil within the next 1000 miles 😆
    • Chuck FB
      OCI, not when but why?

      By Chuck FB · Posted

      I am guessing that engines of that design back then had a better ability to be abused and survive longer than a new design engine with the long timing chain and the overhead cams and phasers etc. But I would never guess that an engine could go that far and not fail spectacularly or at least die a slow death. 
    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      In the 80's 90's I'd run Honda's 7,500 miles between changes using Red Line HP 5W20 and do it for hundreds of thousands of miles with issues. Back in the day it was an SAE 20 with the HTHS of a SAE 30 and SN add load. It was also very polar. Oxidation VOA was over 120. Besides those motors were SPFI and lean burn tech. I could have likely run it longer but never did.    We had a Toyota bought new I ran on Pennzoil's latest and greatest synthetic of the day with "Penthane". A made up word for a very low dose of PAO. Tried 7,500 mile OCI's in that Group III/VI chemistry and the rings tapped out at 90K. Rocker box wasn't as bad as the one Punch put up but it wasn't good either. Also a SPFI motor.    I'm around 3,750 across the board on these GDI monsters and the oil it tapped out by then usually on TBN/TAN crossover and color. Red Line HP Euro.    The AMSOIL SS brochures tell you to follow the OEM values for the service class but that it can be run up to 25K if monitored. I can't imagine what motor could go that distance and not tap out. I've never owned one.    Yes, I know. Lot's of people do. I'm just not going to be one of them. 
    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      I knew a guy in the early 80's that bought a new Monte Carlo and ran it a 100,000 miles without ever changing the filter or the oil. Just kept adding. It looked like that inside.     
    • whenindoubtuseahammer
      My First Project and GMC has me stumped

      By whenindoubtuseahammer · Posted

      Good evening. I was lucky enough to get passed down to me a 2007 GMC LBZ that was my great uncle's. While the underside and rockers are more or less gone I feel like with time I can restore it to working order since it only has 110,000 miles and he put nearly every option he could get without getting the new body style since he did not trust DEF. So far I have done everything I can think of but when I put the key into the ignition nothing happens. I put 2 brand new batteries in it. Cleaned the terminals. Check all the fuses and relays and they all pass with my multimeter. I know I'm missing something that I just cant think of. The only odd thing is the OBD2 port works which makes me think its not the mega fuse. Any advice would be greatly appreciated. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...