6.6 Gas MPG

ickyoldman · January 9, 2020

On 9/8/2019 at 7:28 PM, SierraHD17 said:

Weird. I easily get the 14-15 mpg average with my 2017 6 liter 3/4 ton. That's all highway as there is no urban anything here. And my truck is leveled, 295/60/20 tires and 4.56 gears....

Don't see how......

kenny_r · January 9, 2020

This thread makes me glad I have a 6.6 diesel....

Not when it throws a code, de-rates and leaves you on the side of the road ruining your 3k mile camping excursion [emoji2957]

redwngr · January 9, 2020

34 minutes ago, kenny_r said:

Not when it throws a code, de-rates and leaves you on the side of the road ruining your 3k mile camping excursion

I hear ya, but running them for 12 of last 15 years I've never had one leave me on the side of the road. :thumbs:

Edited January 9, 2020 by redwngr

kenny_r · January 9, 2020

[emoji106][emoji106] for all the guys that have issues with them, there are plenty that go 100-200k miles without a glitch, usually it’s the folks running them hard.

Cowpie · January 9, 2020

16 hours ago, ickyoldman said:

Don't see how......

Matter of driving style. A driver can influence fuel economy by 33%. Fleet studies have shown that. Same vehicles and different drivers.

When I was using regular E10, I could average about 14 mpg with my 2015 2500 6.0 with slightly oversized BFG KO2 rubber and back end dropped 2" for all miles... town, gravel, rural, highway, etc. Highway trips of 95% highway, I could get 17-18 mpg. Not quite getting that now due to using E30 fuel, but the cost is lower so the actual cost per mile is about the same. About the same cost per mile if I was using a diesel getting better mpg, so since I don't need a diesel, I don't have one. Just in my semi truck.

Colossus · January 9, 2020

18 hours ago, redwngr said:

I hear ya, but running them for 12 of last 15 years I've never had one leave me on the side of the road.

I hear ya about the Duramax, I've had 3 of them now, 2 LMMs and a LML, but the emissions stuff (DEF/DPF) did leave me stranded once on the LML. The DPF and DEF was the only real weak link on the the D-Max after they got the injector issues worked out on the first gen. There are days I wish I had a gasser, yet I always go back to being thankful I have a diesel.

ShotgunZ71 · January 10, 2020

2 hours ago, Colossus said:

I hear ya about the Duramax, I've had 3 of them now, 2 LMMs and a LML, but the emissions stuff (DEF/DPF) did leave me stranded once on the LML. The DPF and DEF was the only real weak link on the the D-Max after they got the injector issues worked out on the first gen. There are days I wish I had a gasser, yet I always go back to being thankful I have a diesel.

Indeed, they both have their place and strengths. I really liked my Duramax, but once it was close to warranty, I decided to let it go and get a gas burner. For what I do, which is pull a 5th wheel and my normal driving, the gasser is fine. If we pulled more in a mountainous area, it'd be a different story. Most of our pulls are in foothills and flatlands and if I use it as a DD, it's a 2 mile each way trip. Hearing the engine turn up, especially at elevation, was the biggest thing I had to get used to when I went gasser. Having been around older gas farm equipment, I knew they liked to rev to do the job. I tell folks that laugh to take the turbo off a diesel or put one on the gasser and then compare. Then you'd have an even playing field! LOL! In jest, yes, but a difference maker for sure.

greatmizzou · January 13, 2020

Finished a long driving trip with party of four to illinois to florida and back. Tennesee hills highway got me like 14-15mpg. When I was in coastal Florida on state highways (55-60mph limit)...My computer estimated over 20mpg.

truck drove great, just a pain in the ass to park.

3500 HD crew cab 6.6 gas

Carolina · February 13, 2020

4 remote start warm ups . Mixed driving up 74 on interstate and back roads . Multiple drive thrus . No towing

Limelight · February 13, 2020

I’m finding if I drive it “normally” I get better fuel mileage than if I take it super easy and try to save gas. So far, that’s been the case at least.

I can can tell you as it breaks in I’m definitely starting to feel more and more power. I love this engine so far.

Carolina · February 13, 2020

36 minutes ago, Limelight said:

I’m finding if I drive it “normally” I get better fuel mileage than if I take it super easy and try to save gas. So far, that’s been the case at least.

I can can tell you as it breaks in I’m definitely starting to feel more and more power. I love this engine so far.

It’s the first vehicle I’ve had that seems to get better on cruise versus manually driving it . We’ve had heavy winds all week too . I expect it to do better when the weather calms down

Edited February 13, 2020 by Carolina

texasnavy05 · March 26, 2020

Posting an update with a few more fill-ups.
Truck is daily driver. 80% highway 20% urban. I hook up a 24ft livestock trailer or a 35ft flat deck about 2-3 times per month.

My DIC is consistently 1-2 mpg higher than the real mileage and my "best avg" numbers are way higher than anything I've ever gotten on a tank.

Anybody else using fuelly care to share?

Sent from my SM-G892A using Tapatalk

kenny_r · March 26, 2020

So it basically get the same as a 6.0 if not worse.lol.

I guess on the flip side it is making more hp/tq but it’s also using 3.73’s instead of 4.10’s. Seems like more coulda been brought to the table.

Luke Palmer · May 28, 2020

I just picked up my 2500 gas. In the manual it states to use 93 octane (premium) for best engine performance and best MPG. Ive read this whole thread and I am confused on if majority are using reg unleaded (87 octane) or premium. Pricing here in Cincinnati is on avg 1.99/ gal vs 2.39/gal. Obviously if i am towing i would use 93, I am just wondering if reg is ok or comparable in performance.

ShotgunZ71 · May 28, 2020

On 5/28/2020 at 10:21 AM, Luke Palmer said:

I just picked up my 2500 gas. In the manual it states to use 93 octane (premium) for best engine performance and best MPG. Ive read this whole thread and I am confused on if majority are using reg unleaded (87 octane) or premium. Pricing here in Cincinnati is on avg 1.99/ gal vs 2.39/gal. Obviously if i am towing i would use 93, I am just wondering if reg is ok or comparable in performance.

My truck has almost 9000 miles on it, over 2000 of them towing my 42', 14,300 lb fifth wheel. The only thing I have put in it so far is 87 octane. I'm averaging 7.3 towing, 16 highway and 11.7 overall. Can't say if 93 makes a difference or not when towing, though. Perhaps others up here can shed more light on that aspect. Congrats on the new truck and enjoy!

Edited May 29, 2020 by ShotgunZ71