MPG on 5.7 Hemi

[Fatbob Frank]

I got mine on Sunday and have 100 miles on it, 3.21 4x4 and I’m getting like 11 miles to the gallon, how do you get that?

Highway miles.
My city miles are around 10-12.
Even after I went with bigger (and much heavier) tires I can usually see 20mpgs if I'm road tripping.
My weekly average of mixed town/highway is 16-17 mpgs.
Less if slow moving roadhogs force me to mat the pedal and pass 2 or 3 of them at a shot...

 

[Sportznut]

I have a 2019 - 3.92/5.7 all stock w/13,000 miles

I sold my 2014 3.21/5.7 all stock w/55, 000 miles.


The 2014 w/3.21 consistently got 10% better mpg on the hwy but about the same in city.

87 Octane, driving normal (5 mph over on hwy), hand calculated. Dropped in a can of Seafoam 2X per year.

Both trucks had tonneau covers & carried very little weight. No towing/hauling.

2019 - 15/19
2014 - 15/21

I preferred the 3.21 because it ran lower RPMs on hwy and I drive a lot more hwy miles.

Seemed like the 3.21 was more relaxed at highway speeds because it wasn't working as hard...but I do really like my 3.92 as well. Both ride/rode super smooth.

3.21 was a Big Horn std. suspension. But I did replace the OEM shocks with Bilstein 5100 miles at 40k. Changed to Michelin tires. Much better ride.

3.92 is a Laramie w/really smooth OEM air ride.

I found the mpg on both trucks got a little better after broken in (5-6,000 miles).


Sent from my SM-N960U using Tapatalk

 

[Animus72]

You don't have enough miles on your truck to be concerned just yet. What kind of driving are you doing, city, highway, hills, etc.?

I do a mix of around town and highway, I live in Southern California and its my daily driver.

 

[brian42]

My mileage improved over time but, even then, I was still only in the mid-14s. I'm at 10,000 miles now.

I recently took my truck in for the V71 recall (airbag module). I told them about my mileage and they flashed an update to my PCM (TSB 18-038-19 REV-B for radiator fan on too long and poor fuel economy). I'm getting about 1 mpg better overall now (mid-15s).

I have the 3.21 rear and no eTorque. It's my daily driver but does a lot of highway miles. I usually drive 65-70 mph on the highway.

 

[Glenn54]

This is the best computer MPG I have seen yet. It dropped to 21.x after hauling an air compressor that was higher than the cab for a hundred+ miles, added wind resistance.

 

[Fatbob Frank]

I just hauled my RZR on a 7x12 heavy duty utility trailer and averaged 14 mpgs. That was 2 hours up and 2 back on 2 lanes mostly.
On the trip up I used the tow/haul mode.
On the way back I tried it without using T/H and actually liked it better.
I think I'll reserve that mode for heavier loads...

 

[Gottabdcheese]

Just crossed 3,000 miles.
3.21 w/etorque, mixed driving conditions, stock Big Horn 1500 Crew Cab with the exception of nerf bars. 15-16mpg. 87 octane fuel. Was expecting better.

 

[brian42]

15-16mpg. 87 octane fuel. Was expecting better.

I ran a couple of tanks of 87 octane to try it out and the truck felt a little down on power and my economy was at least 1 MPG lower overall (if not more).

 

[Gottabdcheese]

I ran a couple of tanks of 87 octane to try it out and the truck felt a little down on power and my economy was at least 1 MPG lower overall (if not more).

Been waiting for gas to come down a little before testing 89. Plus Costco only has regular and super premium here.

 

[dano66]

2017 Sport 3.92, 16.8 mpg mixed Shell premium.

 

[brian42]

Costco only has regular and super premium here.

I think that's everywhere. I usually fill up with 91 at Costco unless I need some fuel in between (hard to carve out the time to wait in line during the week). 91 at Costco is about 15 cents a gallon cheaper than 89 at Top Tier stations around me.