1500 MPG highway

[cheerdude63]

Hey peeps,  I have a 15 GMC sierra 1500, it has the max tow package, with a 5.3, 6l80e, and 3.73 gears.  What kind of fuel mileage are people getting with the same set up.  I have some buddies that have similar rides, both 15 GMC's one has 3.08 gears a 5.3 with a  speed and the other is 6.2 and an 8 speed with 3.42 they both get over 24 mpg.  Anyone out there getting 19-20 on the highway like mine?

[goeb34]

2014 6.2 Denali, long tube headers, 3” exhaust bilstein shocks, not sure of gears, 400 mile trip mostly cruise control at 75 mph and got 18 mpg with an avg of 45 mph due to backroads and what not

[RMR]

17 Sierra 5.3, 6L80, 3.42s.  21-22 at 70mph on trips. Mid 18s in town. CAI, Catback Borla and custom HP tune.

[Donstar]

36 minutes ago, cheerdude63 said:

Hey peeps,  I have a 15 GMC sierra 1500, it has the max tow package, with a 5.3, 6l80e, and 3.73 gears.  What kind of fuel mileage are people getting with the same set up.  I have some buddies that have similar rides, both 15 GMC's one has 3.08 gears a 5.3 with a  speed and the other is 6.2 and an 8 speed with 3.42 they both get over 24 mpg.  Anyone out there getting 19-20 on the highway like mine?

Everything else being equal, yours is the best combination in my opinion.  The towing capability is outstanding and you use regular gas. Driving habits  greatly impact mpg's but nothing wrong with 19-20 mpg's! 

[mookdoc6]

10 minutes ago, Donstar said:

Everything else being equal, yours is the best combination in my opinion.  The towing capability is outstanding and you use regular gas. Driving habits  greatly impact mpg's but nothing wrong with 19-20 mpg's! 

It probably is/was!

[cheerdude63]

52 minutes ago, goeb34 said:

2014 6.2 Denali, long tube headers, 3” exhaust bilstein shocks, not sure of gears, 400 mile trip mostly cruise control at 75 mph and got 18 mpg with an avg of 45 mph due to backroads and what not

Are you 3 inch all the way back? Dual or Single?

[goeb34]

Are you 3 inch all the way back? Dual or Single?

3” duals from collector back to 5” tips, dynomax mini race bullet mufflers

[Paintor]

I get over 19mpg with a performance tune, Zone body lift, 2” leveling kit to raise the front, front air dam sawzalled in half..and V4 disabled.

 

Computer lies and says I get 16mpg. Tire size is stock but a different brand.

 

Don’t trust the computer. It lies, 

Speed signs along highway match dash display.

[Jacoby]

If you’re all stock the 20’s shouldn’t be an issue. Once you start lifting and changing tire size then say goodbye to those mpgs 

[dsatwork]

I have 2015 Silverado 500, with the max tow package, 5.3, 6L90, and 3.73 gears.My mileage dropped considerably after I added larger E Rated 10 PLY tires for towing my 27" airstream trailer. Computer shows it went from over 20 consistently to 17 to 18 MPG highway miles.

[300 Blackout]

1500 CCSB 5.3 6L80 4.56 long tubes w/ dual 3” exhaust and x pipe. Sitting on 275/65R20 STT Pro and a front level. AFM disabled. 12mpg around town and 17-18 on the highway. Direct correlation between how thirsty she is and how heavy my foot feels. :-)

[martinto]

Trip from SC to northern OH.  2016 Sierra 6.2 8 speed, MAX tow pkg, 3.42 gear.  Consistently hit 24 MPG highway once out of the Smokies.  Last 400 miles heading home and through the Smokies...21.8 MPG.  Of course when I pull 6500lb TT, it’s 10-12 MPG.  I got no complaints.

[SkiDooNick700]

I can provide you realistic numbers.

 

I average between 19 to 20, closer to 19 on the highway going 75mph and even some 80mph.

 

I average 16-17.5 in the suburbs commute to work and back,  with speed limits anywhere from 25mph to 45mph and stop lights every mile.  

 

Your buddies that get over 24mpg are either

1) being misinformed by computer display

2) lying

3) have an ideal commute of 50 to 60mph with minimal stops everywhere they drive

 

6.2l 8 speed with 3.42s, max tow package. 

[ES44AC]

My Stepfather's 2018 5.3 gets about 20 mpg @70 mph , no idea what gear.

 

My 2018 6.2 w/3.42 gets 22 mpg or a little more sometimes around 70 mph. 

[martinto]

On 7/11/2019 at 9:33 PM, SkiDooNick700 said:

I can provide you realistic numbers.

 

I average between 19 to 20, closer to 19 on the highway going 75mph and even some 80mph.

 

I average 16-17.5 in the suburbs commute to work and back,  with speed limits anywhere from 25mph to 45mph and stop lights every mile.  

 

Your buddies that get over 24mpg are either

1) being misinformed by computer display

2) lying

3) have an ideal commute of 50 to 60mph with minimal stops everywhere they drive

 

6.2l 8 speed with 3.42s, max tow package. 

I’ll go with door #1...but “misinformed” is a stretch.  Of course the algorithm that calculates the MPG has a plus/minus tolerance, but it’s probably in the range of 2-4%.  Your 16-17.5 is consistent with my mileage in the suburbs.  A limited 24MPG is not uncommon in good conditions at highway speeds.