6.6 Gas MPG

brendon444 · September 8, 2019

What are guys getting for MPG with the new 6.6 Gas? The MPG is what has held me back from purchasing a 6.0 2500 in the past. Currently tow 8600lbs with my 1/2 sierra , but also daily drive my truck so yes MPG does matter to me.

ShotgunZ71 · September 8, 2019

Went on a trip yesterday about 300 miles total. Half was interstate going 65-75 and the other was rural. The trip odometer was at 16.7 mpg when we got home. Pulling my 36', 9500# TT last weekend, I got 8.6 mpg overall. Only 1200 miles on it, so time will tell if it increases any with a few more miles.

kenny_r · September 8, 2019

So basically the same numbers as the 6.0. Only thing I can see different is the in town driving. Not too bad considering it has 40 more hp’s and 80 more ftlbs. You also gotta factor the 3.73’s.

brendon444 · September 8, 2019

That considerably better than a 6.0. All my work 6.0 get 12mpg unloaded

Pastusak.t · September 8, 2019

My average tank on my 6.0 is 11.2 and it’s mostly in town. I’d say 80% in town. But even on the hwy unloaded I’d be lucky to see 14/14.5 mpg. So 16.7 sounds a lot better.

kenny_r · September 9, 2019

My average on stocks at this moment is 15-17 on hwy doing roughly 65-70mph and 11-12 town. Average bout 8 towing our toyhauler. So that 6.6 on the hwy and towing seems to be on par with the 6.0.

With bigger wheels/tires I’m roughly 10-11 town, 14-15 hwy, nearly the same towing as with stocks which is odd.lol.

SierraHD17 · September 9, 2019

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....

brendon444 · September 9, 2019

11 hours ago, 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....

I’m sure that’s in perfect conditions. Reality is the 6.0 gets bad mileage. I’ve had 7 of them up to 2014.

Might squeeze 14 on highway but usually 12 average

cmysstailights · September 9, 2019

Can the 6.6 run e85, have not found it anywhere. My 15 6.0 I see 7mpg towing 10k lbs, 8city and 12.5 hwy

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Booger T · September 9, 2019

1 hour ago, cmysstailights said:

Can the 6.6 run e85

No e85, my wife is currently getting about 12 mpg to and from work and 16-17 highway with her new 6.6. Haven't towed travel trailer with it yet. Currently have 900 miles on it. Her old truck which was a 2007 6.0 would usually get 15-16 highway, towing trailer around 8 mpg

Donstar · September 9, 2019

On 9/8/2019 at 2:47 AM, brendon444 said:

What are guys getting for MPG with the new 6.6 Gas? The MPG is what has held me back from purchasing a 6.0 2500 in the past. Currently tow 8600lbs with my 1/2 sierra , but also daily drive my truck so yes MPG does matter to me.

The mpg's of the current 2500 equipped with the 6.0 is not horrible and remind me of the pre Vortec, fuel hungry 1/2 tons. However, I agree they are bad enough though to seriously consider whether using a 2500 as a DD makes sense. There was a time when it was a viable option for me to have a second vehicle to absorb some of those daily driver duties. The amount and type of driving you do will determine whether a second commuter car is worthwhile, but it worked in my situation. Arguably, the $'s saved may not have made owning an extra car lucrative but seeing the miles stay low on my truck was truly a bonus!

protovack · September 10, 2019

its looking like people are able to get 16-17mpg out of it, which is not bad and definitely better than the 6.0. Might even improve by 1mpg after 10,000 miles or so.

Edited September 10, 2019 by protovack

SierraHD17 · September 10, 2019

17 hours ago, brendon444 said:

I’m sure that’s in perfect conditions. Reality is the 6.0 gets bad mileage. I’ve had 7 of them up to 2014.

Might squeeze 14 on highway but usually 12 average

Nope... that's called driving down the highway. If you knew anything about where I live you would realize quickly "perfect" conditions are a fantasy. This 17 is my 6th 6 liter truck and gets better mpg than my others... My old trucks with 4L80e's were worse... I don't even remember what my 09 got lol.

Edited September 10, 2019 by SierraHD17

brendon444 · September 10, 2019

6 minutes ago, SierraHD17 said:

Nope... that's called driving down the highway. If you knew anything about where I live you would realize quickly "perfect" conditions are a fantasy. This 17 is my 6th 6 liter truck and gets better mpg than my others... My old trucks with 4L80e's were worse... I don't even remember what my 09 got lol.

My experience is with the 06-13 trucks. Mine were all in that year. dependable but not great on fuel lol.

bg1988 · September 10, 2019

On 9/8/2019 at 4:46 PM, brendon444 said:

That considerably better than a 6.0. All my work 6.0 get 12mpg unloaded

I win i get

22city-25MPG highway

next time buy the hybrid 6.0L engine 379HP @5100RPM 472ft-lb torque @4100 rpm

the minimum torque is 320 @ any RPM even with v4

she will spin the wheels at a dead stop even done it in front of a police officer (happened accidentally while turning) i did not get a ticket since the officer was too busy giving a ticket to someone else!

Edited September 10, 2019 by bg1988