271 mile rd trip to Poconos today, averaged 19.9 mpg

GRN69CHV · October 26, 2016

Thought that was pretty good. Very heavy traffic early this morning and on the way home this evening, a lot of stop and go getting to/from PA476 and 45 mph speeds at the construction zones. Once was able to run open highway, set the cruise at 70 mph, truck was very happy on the rolling hills in 6th gear, never down shifted. Considering I have AFM disabled, I think this is admirable.

Dnt · October 26, 2016

Pretty Good.

2016 Denali 6.2 8spd 3.23 Only changes from factory are a Hypertech premium fuel tune with AFM only active above 50mph / Peragon bed cover / GM Borla catback dual exhaust. Right at 8500 miles so far with average at 20.7mpg . The pic below was from a recent trip to Chicago. I think it will do a bit better after it has gotten completely broken in. Only got around 24mpg coming back but hit the speed limiter (98mph) at least a half dozen times LOL

You would think a 5.3 with 3.08 gears would be closer to 30mpg rather than 20mpg?

wuznme · October 27, 2016

My blown 6.2 few weeks ago 260 mile trip got 19.6

Dnt · October 27, 2016

Mileage on these 6.2 8spd's is crazy good.

Man I want a Whipple supercharger soooooooo bad........... wuznme is our test bed to see how the Whipple holds up long term LOL

wuznme · October 27, 2016

I'm for sure testing it!! Smaller pulley on the way too.

Sean Neilan · October 27, 2016

My lifetime average for my 2015 5.3L Sierra at 23k miles is 16 =\. But I'm in Long Island and until a few months ago lived in a town that had 36 traffic lights in a 3 mile stretch of road sk 60% of your time was spent idling at red lights.

tnchevy · October 27, 2016

The last time I checked my spreadsheet I am at 19.2 mpg hand calculated (trip B which has never been reset says 19.8 mpg). This is 2 years and 1 month and 15k miles. All stock except for removing the air dam last November. I will let you guys know my avg's from 1 year with the air dam on and 1 year with it off but so far the difference is only 0.2 mpg less. When my 5 year warranty is up I plan on getting one of the tuners and turning AFM off and finally putting on an exhaust where I don't have to hear the crappy sound when in V4 with the gas barely pressed.

ShamrockShooter · October 28, 2016

First post was that avg computer or hand Calc? My computer display is always .7 to .8 MPG higher than I get long hand. Probably because of the 10% ethanol fuel

tnchevy · October 28, 2016

First post was that avg computer or hand Calc? My computer display is always .7 to .8 MPG higher than I get long hand. Probably because of the 10% ethanol fuel

Not because of the ethanol, just about every vehicle over estimates the mpg's compared to doing it by hand. My Jeep is always 1.2 mpg off, my silverado is usually 0.8 mpg off, my Ford work truck is 1.1 mpg off, and my motorcycle is almost 2 mpg off. I keep spreadsheets for fuel mileage on all my vehicles so it eventually averages out with the use of different pumps, temps, etc.

BigBadSierra · October 28, 2016

It's way better the n the 8 to 10 mpg I get towing the camper ha ha.

Sean Neilan · October 28, 2016

First post was that avg computer or hand Calc? My computer display is always .7 to .8 MPG higher than I get long hand. Probably because of the 10% ethanol fuel

I use calculate by hand as well and compare it to my computer and the computer was spot on every time. I don't know if the lifetime is as accurate, but by the tank I've had no differences.