6.6 Gas MPG

Pastusak.t · December 6, 2019

1 hour ago, Cowpie said:

The average mpg of commercial semi trucks has almost doubled in the last 20 years. Doing the same work on the same terrain in the same weather. And the average HP and Torque of engines has gone up as well. Meanwhile, the average trailer length has gone from 48' to 53'. Even with all the diesel emissions stuff that got piled on just like the pickups got. And there was no government CAFE stuff forcing OEM's to improve mpg of semi trucks over that period. The heavy truck OEM's did it to gain market share. They did it to improve customer cost benefit ratios. They put their R&D people to work.

The OEM pickup manufacturers cannot make the same claim to have doubled average mpg in the last 20 years of pickups within any class. A little bit of an uptick, but certainly not doubled. And it wouldn't have improved much at all if the pickup OEM's had not had the government breathing down their throat about fuel economy. My '98 2500 454 averaged 12-13 mpg for all miles . My 2015 2500 6.0 only gets about 1-2 mpg average better fuel economy than that for all miles. And the new 6.6 gasser numbers have not added much to that. If the pickup OEM's had accomplished the same thing as heavy commercial trucks, the average MPG for all miles of a modern 2500 gasser would be at least 20 mpg. That average including highway, city, hauling, everything. Diesels in pickups would be averaging in the high 20's mpg for all miles as well, not just highway mpg.

The average price of a new pickup has virtually doubled in the last 20 years though. Even while the average price of a new heavy commercial truck has only gone up 50% in comparison. So the pickup OEM's have exceeded the cost growth compared to heavy commercial trucks.

So let’s ask this question. You constantly rant on here about how your semi is far superior to a pickup in all aspects of driving. Why do you even own a pickup. Shouldn’t you, by your claims, be driving a semi as a daily driver. Probably not. There are all kinds of reasons why that would be impractical. Also, the big rig semi oem’s have way more incentive to increase fuel mileage and the customer would gladly pay for better fuel economy because it affects their bottom line. The average consumer on a pickup wouldn’t pay a premium for fuel economy, as I’ve seen you argue in the diesel vs gas issue. You personally bought a gas instead of a diesel because the diesel, even tho it gets far better fuel economy, won’t pay for itself for a long time. There is a business decision that is being made here and on a consumer pickup, fuel economy isn’t as important for most as other features may be. You already have a option for better fuel economy in a diesel version of the same truck and as you know those sell about 30% to gas 70%.

Not saying that you are wrong about it being possible, just not practical. This isn’t a case of “if you build it they will come“.

Cowpie · December 6, 2019

1 hour ago, Pastusak.t said:

So let’s ask this question. You constantly rant on here about how your semi is far superior to a pickup in all aspects of driving. Why do you even own a pickup. Shouldn’t you, by your claims, be driving a semi as a daily driver. Probably not. There are all kinds of reasons why that would be impractical. Also, the big rig semi oem’s have way more incentive to increase fuel mileage and the customer would gladly pay for better fuel economy because it affects their bottom line. The average consumer on a pickup wouldn’t pay a premium for fuel economy, as I’ve seen you argue in the diesel vs gas issue. You personally bought a gas instead of a diesel because the diesel, even tho it gets far better fuel economy, won’t pay for itself for a long time. There is a business decision that is being made here and on a consumer pickup, fuel economy isn’t as important for most as other features may be. You already have a option for better fuel economy in a diesel version of the same truck and as you know those sell about 30% to gas 70%.

Not saying that you are wrong about it being possible, just not practical. This isn’t a case of “if you build it they will come“.

My 3/4 drive socket set is far superior to my 3/8 drive socket set also. But then why do I own both? I have tools for the job I need to get done. Just that simple. My 3/4 ton pickup is better at tasks around my property than my semi truck is. It is also better at making quick part / oil runs, pushing snow, etc. But on the road, my semi puts a 3/4 ton pickup to shame, even a diesel version. I guess, why do I also own a John Deere Gator? Wouldn't the 4x4 pickup suffice? Nope, not in all situations. A pickup is just a tool for me. Pure and simple. And I have different tools for different jobs.

Oh..... my semi truck IS my daily driver. When I go to work, I walk out of the house and get in the Semi. I don't drive to work with car or pickup.

But that doesn't negate the fact that pickup truck OEM's have not kept pace with the developments of the heavy truck OEM's while at the same time inflating prices at a higher percentage than heavy truck OEM's have. Anymore, even the wild creature comforts that the pickup truck OEM's put in their pickups is being matched, and in some ways exceeded, by the heavy truck OEM's. As far as use on the road, my semi truck is far superior and comfortable to drive than my pickup.

I have given thought to going to a single drive axle and cutting the frame shorter and using the semi to yank around a 5th wheel RV I may opt for in retirement. At least in the semi truck I will have air ride seats, a built in refrigerator, 10" GPS navigation, Bose surround sound, etc that it already has. Heck, I can literally get up out of the seat and switch drivers with the truck moving down the road if I wanted to. And the visibility is far superior than any pickup truck.

Edited December 6, 2019 by Cowpie

Pastusak.t · December 6, 2019

1 hour ago, Cowpie said:

My 3/4 drive socket set is far superior to my 3/8 drive socket set also. But then why do I own both? I have tools for the job I need to get done. Just that simple. My 3/4 ton pickup is better at tasks around my property than my semi truck is. It is also better at making quick part / oil runs, pushing snow, etc. But on the road, my semi puts a 3/4 ton pickup to shame, even a diesel version. I guess, why do I also own a John Deere Gator? Wouldn't the 4x4 pickup suffice? Nope, not in all situations. A pickup is just a tool for me. Pure and simple. And I have different tools for different jobs.

This is exactly my point.

All I’m saying is a pickup is designed for a specific market. And that market doesn’t allow for a crazy high selling price. Average transaction price of a pickup is in the 40k neighborhood. Your semi is 150k plus. That extra 90k goes an awful long way to r&d and creature comforts.

Now sell a 3/4 or 1ton for 150k and I bet they’d be on par with each other. I’m also sure they wouldn’t sell at all. It wouldn’t make sense to spend billions on r&d and not get a return on it.

As far as the creature comforts that are in your semi... they sure as hell better be there for the asking price. All I’m saying is your not comparing apples to apples.

Listen I know I’m getting you all rev’d up (pardon the pun) but there is obviously a reason every manufacturer on earth hasn’t figured this out yet. And if you think it is so easy to accomplish then I’m sure you’ll have your pick of oem’s to work for because the first manufacturer to accomplish it will dominate in sales.

I read this forum almost every day and I agree with you on most every issue but to say oem’s can achieve a far better fuel economy number and just choose not to isn’t real world. There are other factors there we may not be seeing.

Tom Snider · December 8, 2019

Just finished a trip from Oregon to Texas (3964 miles) round trip. Trip computer states 16.7 for the trip. Averaged 18 mpg on the interstate, in town still draws down the fuel. Lots of power.

Donstar · December 12, 2019

On 12/6/2019 at 6:40 AM, Cowpie said:

The OEM pickup manufacturers cannot make the same claim to have doubled average mpg in the last 20 years of pickups within any class.

Not arguing but picking up on this point. Double and 20 years may not be correct but pickups have come pretty close to this when comparing mpg's of trucks with equivalent horsepower.

Christopher Murphy · December 14, 2019

Went on a 350miles trip this weekend and weighed in at 16000lb with my 28’ toy hauler. Got 7Mpg from St. Louis to Cape Girardeau And 6mpg back up. That was at 65mph. Truck ran with cruise set and basically stayed at 3000rpm the whole way down and back on HWY55. Started with 500miles on the truck.

This isn’t what I was hoping for. It’s gonna be an expensive tow anywhere we go now.

cmysstailights · December 14, 2019

Went on a 350miles trip this weekend and weighed in at 16000lb with my 28’ toy hauler. Got 7Mpg from St. Louis to Cape Girardeau And 6mpg back up. That was at 65mph. Truck ran with cruise set and basically stayed at 3000rpm the whole way down and back on HWY55. Started with 500miles on the truck.
This isn’t what I was hoping for. It’s gonna be an expensive tow anywhere we go now.

Thats why i am leaning towards the diesel this time. My fear is make the same mistake twice.

Sent from my SM-G960U using Tapatalk

Christopher Murphy · December 15, 2019

I was also concerned going in but realized that the 10k extra for diesel along with the additional cost of fuel would only benefit if I were to pull that heavy all the time. I think someone figured it would be 130k mikes to make up the difference.

Being a second truck I think those pulls will be a few times a year and just have to suck it up. If you plan on pulling a lot and heavy I would suggest going for the diesel if your pocket can accommodate it.

cmysstailights · December 15, 2019

I was also concerned going in but realized that the 10k extra for diesel along with the additional cost of fuel would only benefit if I were to pull that heavy all the time. I think someone figured it would be 130k mikes to make up the difference.
Being a second truck I think those pulls will be a few times a year and just have to suck it up. If you plan on pulling a lot and heavy I would suggest going for the diesel if your pocket can accommodate it.

This is my primary daily driver. Tow a 6k cargo trailer weekly and a 11k lb tt during the season

Sent from my SM-G960U using Tapatalk

i82much · December 15, 2019

as far as semi vs. pickup fuel economy, i suspect if you were to calculate the frontal area and drag coefficients and take a good look at exactly where the losses are coming from that their respective fuel economy numbers would not be so surprising. the weight and length of a semi are proportionally far greater than that of a pickup as compared to the frontal area. on the open road at highway speed, aero is going to be the biggest factor in fuel economy so the numbers posted previously are not that unreasonable.

ShotgunZ71 · December 15, 2019

14 hours ago, Christopher Murphy said:

Went on a 350miles trip this weekend and weighed in at 16000lb with my 28’ toy hauler. Got 7Mpg from St. Louis to Cape Girardeau And 6mpg back up. That was at 65mph. Truck ran with cruise set and basically stayed at 3000rpm the whole way down and back on HWY55. Started with 500miles on the truck.

This isn’t what I was hoping for. It’s gonna be an expensive tow anywhere we go now.

Is that 16k your combined weight or just trailer weight? I'm in the 7-7.5 range when towing my 42', 14300 5th wheel. Higher speeds with the drag are your biggest deterrents, not the weight. My gross weight of both was 21800 all loaded up a few weeks ago.

When I had my Duramax, my towing MPG was about 2 mpg more. Nothing earth shattering. The highway unloaded MPG is where I've seen the biggest difference, around 3 mpg. City driving, stop and go and the gasser is even and maybe less than 1 mpg better.

I recently did some figuring of costs, and my mileage during 24000 miles using my old diesel mpg and my Ford gasser. The gas would have cost me $125 more per year. It would take a while to make up the difference for my use. No doubt the diesel pulls effortlessly, but the gas certainly does not struggle at all.

Edited December 15, 2019 by ShotgunZ71

JoeCarGuyCT · January 5, 2020

First I want to THANK everyone who posted information on the actual MPG you are getting with your GM 2500HD with the 6.6L engine.
I have a 1998 GMC Sierra 1500 Extended Cab with the 8 foot longbed and it is time I must replace it. The GMC Sierra served me well with over 250K miles. I custom ordered in August of 1997 and paid $29,000. Replacing today with the 2500HDLT is stickered at $54,000 so not double the cost - and todays model is equipped with many more options and more technology.
I need tp replace with a new truck which is more dependable for trips I will be taking from New England down to Florida several times a year so it is time.
I am a GM guy and really want to buy another GM. I would buy a Chevy Silverado 1500 Double or Crew cab IF it was available with an 8 foot longbed. I need an extended cab and MUST HAVE an 8 foot longbed as I do a lot of construction / renovation work and need the 8'x4' materials to be inside the bed with the tailgate closed.
I am very disappointed that GM does not have a double cab or crew cab with an 8' bed only the regular cab.
If I want a GM with a back seat and 8' longbed I must now go to the 2500HD model. I am concerned about the hit on gas mileage with the 6.6L engine. No I do not want Diesel.
I see the 2020 2500HD has a 6.6L V8 Direct Injection with Variable Valve Timing Gas engine, 3.73 rear axle ratio Paired with a 6-speed automatic transmission and 17" LT265/70R17E all-terrain tires. I am waiting for the 2021 model to see if the 10 speed transmission will be included which may help with mileage.

I have found that FORD has the F-150 Lariat model available with the Super Cab (same as the GM Extended Cab with suicide back doors) and an 8 foot longbed. This would meet my needs but it is a FORD
The Ford has a 3.5L V6 EcoBoost® Engine with Auto Start/Stop Technology, Electronic Ten-Speed Automatic Transmission with Tow/Haul and Sport Mode, 4X4, 3.55 Electronic Locking Axle Ratio and 275/65R 18 OWL A/S & A/T Tires.
The F-150 truck is rated as GCWR=17,100, truck weight 5,000lbs and has a Max Tow=11,600.
The Fuel MPG= 16city,22hwy and 18combined.
I checked the FUELLY site and shows avg of 18MG combined with +/- 0.54 error for the Ford 3.5L Eco. There is no breakdown on Chevy or GMC 6.6L engine.

I can handle the gas bill for 18MPG avg hoping highway would be 20MPG but seeing the 12 - 14 MPG numbers many are posting is concerning as this will be my daily driver as well as travel vehicle. And 6- 8 MPG when towing is significantly low.

Appreciate any feedback. Thank you again.

Joe

MORSNO · January 6, 2020

Anything over 12 is an empty HD truck, they are just much heavier than a 1500 and could never pull off the mileage numbers. I carry a 3,200lb camper in my 2500 6.0 and get 8-10 which is normal, a 1500 couldn't carry half that weight so I suck it up and live with lower mileage for the ability to carry and tow heavy loads safely. You'll also notice that parts last longer on a HD over a 1500, even brakes last forever.

IdoMRI · January 6, 2020

Had a 2018 Ford Eco 3.5tt max tow package with the 3.55 rear and when towing mileage goes down pretty fast and inclines here in the mountains and summer heat my temps would climb crazy fast with the turbos going, one of the reasons switched to a HD. Decided on GM after doing my test drives and comparing things that makes towing easier. GM sold me with the cameras set up and HUD which put them 1st above the others for my choice. I went diesel this time only because my new trailer I just purchased is 14k and I pull up steep grades on all my destination areas.

My daily driving unloaded in town real numbers with the eco was 14ish. Highway 18-19. When I hand calc Lie o meter was always 1- 2 mpg over real number. Towing 5k AVG 6-7 at 63-65mpg would drop to 5mpg at 70mph "speed limit is 75". My best I ever achieved was doing whole trip at 55 and got 8mpg.

Edited January 6, 2020 by IdoMRI
added fuel numbers