MPG: 6.2 with 8 speed

ConnRadd · April 8, 2015

I'm sure there are several postings on MPG, i understand if this post needs to get redirected.

Having more 6.2s with 8 speed tranny on the streets now, what's real world expectations?

I'm impressed on what the factory claims, but I'm sure 99% of us don't drive in there testing conditions.

I know on my 2012 Avalanche, I averaged 17 with factory tires. Then dropped 2 mpg once I put the Coopers on.

Stoddard · April 8, 2015

I have one. '15 crew cab regular box. I have 305 55 r20 all terrains and pull about 13 city, 14-16 highway. Highway speeds 70-85mph. The slower I go the better it is. Mostly flat ground. I know the bigger tires hurt it some and have under 4k miles on it. Been running 91 up here in SD.

In my opinion kinda crappy for what they claim.

CounterMeasure · April 8, 2015

I get ~15.5mpg, which is a mix of city and some highway driving. I've gotten closer to 17 if I baby it around, but that defeats my purpose of getting a 6.2. It does really good on the highway at 70 if I don't have a headwind. I've averaged 21-23 on certain highway drives. Although, it falls off quickly if I go above 70.

ConnRadd · April 8, 2015

I get ~15.5mpg, which is a mix of city and some highway driving. I've gotten closer to 17 if I baby it around, but that defeats my purpose of getting a 6.2. It does really good on the highway at 70 if I don't have a headwind. I've averaged 21-23 on certain highway drives. Although, it falls off quickly if I go above 70.

You have any upgrades or is it stock?

Dunc · April 8, 2015

I have a crew cab, standard bed, 4wd. I get anywhere between 15.6-17.7mpg with a mix of highway and city. My best was 22.1, but I would say the average is closer to 15-16mpg. I have two 14 hour trips coming up this summer. Will be interesting to see what I can get with 100% highway driving.

EDIT: I should also add that I use the remote start everyday. The truck is usually idling for 5-10 minutes before I get in and start going so my average might be a tad lower than it could be.

P-Funk · April 8, 2015

My average is 18mpg since I got it. Fairly even mix of city and highway.

ConnRadd · April 8, 2015

I have a crew cab, standard bed, 4wd. I get anywhere between 15.6-17.7mpg with a mix of highway and city. My best was 22.1, but I would say the average is closer to 15-16mpg. I have two 14 hour trips coming up this summer. Will be interesting to see what I can get with 100% highway driving.

What octane do you use?

CounterMeasure · April 8, 2015

You have any upgrades or is it stock?

Other than a catch can and Michelin LTX M/S2 tires, its stock.

redwngr · April 8, 2015

Like most vehicles, it depends how it is being used.

Mine is lifetime 18 over 4447 miles.

Current tank is 19 over 208 miles

Best 25 is 24.8.

It's relatively flat around here.

Often take 50 mile trip combining freeway and rural. Easily runs over 20 doing that trip.

BluByU14 · April 8, 2015

When I had my 6.2L 8-Speed I averaged around 18 MPG lifetime over 4000 miles. On a 2500 mile road trip which was mostly highway, but did have stop/go traffic, some secondary street, and an average highway speed of 74-80, I averaged over 20 MPG's.

Bill_F · April 8, 2015

I am normally showing my last 25 at between 14-14.5 - I drive only 4 miles to work, and it is all city, so this doesnt really bother me any.

Best 25 is 25.4 MPG which was on a trip to Galveston from Houston. I am only at ~1025 miles, so, it will probably rise a tad, but not much given my normal commute is all city.

Check fuelly, you will get figures in time. I think it skews a tad high though, because if you are tracking it, i think you tend to be conscious of how you drive. Currently there are only 2 of us reporting FE numbers out of 4 total 6.2 Sierras, there is only 1 Silverado, but he has no fuel ups, so I am not bothering to link to it.

http://www.fuelly.com/car/gmc/sierra_1500/2015/all?engineconfig_id=9308&bodystyleconfig_id=&submodel_id=

DallasZ71 · April 8, 2015

I've been averaging between 16-17 MPG per tank (by math) driving back and forth to work which I would classify as mostly city driving with a few stretches without stop lights. On a recent 500 mile road trip I averaged 22mpg one way and 19 mpg coming home. Driving to work there isn't a lot of room to get on it much, but I do when I can.

My Truck is a 6.2 4wd Denali Crew short bed all stock. I have around 1700 miles on it as of now.

Overall I am pleased with what I am getting considering the 5.3 2wd SLT crew demo I had for 2 weeks prior to my truck arriving was only averaging 17 mpg driving the same routine.

CounterMeasure · April 8, 2015

Best 25 is 25.4 MPG which was on a trip to Galveston from Houston.

Gulf coast tailwind FTW!

Edit: Wait, you said Houston to Galveston, which would have been a headwind normally. If you got that good going there, you should have had even better numbers heading back to Houston.

Bill_F · April 8, 2015

Nope, more traffic on the way home. That was on the way there, maybe the elevation drop from like 30 ft to 7 played in LOL.

My last car was a diesel golf, I averaged 47 lifetime in it (rated at 30 city / 42 highway). So I am pretty good at getting it up there if I try. I had a full TANK hit 51.4 in that car.

Best simple hyper-milling trick to live with, is just get off the gas earlier (this is the only trick I still use in the truck).

When you know you have to stop, just get off the gas. Let the truck engine brake as long as it can... no fuel use, and it saves your brakes, plus, the light is more likely to turn green before you get there, so you get to save additional fuel by getting a rolling start from 10 instead of starting from a stop. Same applies for traffic, if you know you are going to have stop due to traffic, just let off the gas earlier, take advantage of the engine brake as long as you can.

CounterMeasure · April 8, 2015

Best simple hyper-milling trick to live with, is just get off the gas earlier (this is the only trick I still use in the truck).

When you know you have to stop, just get off the gas. Let the truck engine brake as long as it can... no fuel use, and it saves your brakes, plus, the light is more likely to turn green before you get there, so you get to save additional fuel by getting a rolling start from 10 instead of starting from a stop. Same applies for traffic, if you know you are going to have stop due to traffic, just let off the gas earlier, take advantage of the engine brake as long as you can.

I am surprised you can get away doing that in Houston driving culture. While Austin area isn't much better, my experience in Houston is if you leave 6 inches between you and the person in front of you, someone will fill immediately that gap.