What kind of mileage are you getting with a Hemi and 3.92 gears?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

CanuckRam1313

Senior Member
Joined
Aug 29, 2022
Posts
1,294
Reaction score
2,855
Location
Ontario Canada
Ram Year
2023 Warlock SLT
Engine
5.7
Not as good as I did with my 19' Classic HEMI with 3.21 gears ;)

I just bought a new 2023 Classic Warlock with the 3.92's a few weeks ago.

Love the 4th Gens, and while I do notice more fuel consumption, it's not too bad.

At 120KM/H with 3.21's I was at about 1400/1500 rpm's
At 120KM/H with 3.92's I am at about 2000 rpm's

Also, with new engines, they require 5,000 to 6,000 miles to really break in well and settle in before you'll see its optimal fuel economy capabilities.

However, how you drive it also greatly affects your consumption as the 3.92's like to jump off the line like a jack rabbit with a heavier foot.

I'd also recommend a good synthetic oil when you start changing it, and quality fuel, too.
These things also help with efficiency and with longevity of your HEMI as well.
 

Daviddnv

Junior Member
Joined
Nov 10, 2021
Posts
28
Reaction score
18
Location
Orlando/Daytona Beach, FL
Ram Year
2022
Engine
Hemi 5.7
Lots of mileage posts on here... I have 22 bighorn, quad cad, 4x4 with 3.92. This was a trip I took just over a year ago, mostly flat FL highway mileage. This was with 89 gas. Around town I get about 16 to 17. I use 93 gas now, I think I get a better percent increase in mileage then the percent increase in cost per gallon.

1710958305464.png

--David
 

TotallyHucked

Senior Member
Joined
Feb 23, 2023
Posts
409
Reaction score
739
Location
Gainesville, Ga
Ram Year
2017 Sport CCLWB
Engine
5.7
'17 CC 6.4' bed (i.e. heavier) 4x4 Sport with everything but a sunroof, Hemi 8-speed 3.92s. With a 2" level and E-load stock sized tires got 17-19 mixed, 19-21 on the hwy. Now with 35x11.50s and a 3" level, 15-16 mixed (also winter fuel could be a factor, might gain 1mpg back with summer fuel) and haven't been on the hwy long enough yet to know.
 

Burla

Senior Member
Military
Joined
Apr 28, 2012
Posts
23,561
Reaction score
45,931
Ram Year
2010 Hemi Reg Cab 4x4
Engine
Hemi
It's all related to rpm, you can get the same mileage as 3.21's if you have it in lower rpm's, as in drive a little slower on the freeway. The good news is you cant adjust 3.21's to give you the benefit of 3,92's. Can handle larger tires and loads. They are very desirable imo.
 

CanuckRam1313

Senior Member
Joined
Aug 29, 2022
Posts
1,294
Reaction score
2,855
Location
Ontario Canada
Ram Year
2023 Warlock SLT
Engine
5.7
It's all related to rpm, you can get the same mileage as 3.21's if you have it in lower rpm's, as in drive a little slower on the freeway. The good news is you cant adjust 3.21's to give you the benefit of 3,92's. Can handle larger tires and loads. They are very desirable imo.
Agreed.

What I'm noticing with the 3.92's is that on the highway I'm not continually shifting in and out of 7th & 8th gears like I did with the 3.21's.

This is a huge bonus for me in terms of driving comfort and reduced wear and tear on my transmission.

I'll gladly sacrifice some fuel for a happier truck. I'm also looking forward to when I put my 35's on soon, too.
 
Last edited:
OP
OP
W

Weekiman

Member
Joined
Mar 7, 2024
Posts
89
Reaction score
46
Location
WEEKI WACHEE
Ram Year
2023,2024
Engine
5.7 Hemi
Lots of mileage posts on here... I have 22 bighorn, quad cad, 4x4 with 3.92. This was a trip I took just over a year ago, mostly flat FL highway mileage. This was with 89 gas. Around town I get about 16 to 17. I use 93 gas now, I think I get a better percent increase in mileage then the percent increase in cost per gallon.

View attachment 539739

--David
Nice, I'm also in Florida. I'm sure there is many posts. Thanks for the reply!
 

RamInfo

Senior Member
Joined
Nov 6, 2015
Posts
324
Reaction score
329
Location
Utah
Ram Year
2016
Engine
5.7L HEMI
My 2016 on the highway ranges from a hand-calculated high of 21 to a low of 16. It all depends upon wind, weather, speed, terrain and whether I’ve filled with 88 or 91(pure) as I’m usually running empty or with a very light load. And I do run a tonneau cover, which helps with mileage. The drop in mileage from the 392s is worth it to me for those times when I really, really need to get up to speed in a hurry…

Best,
dg
 
OP
OP
W

Weekiman

Member
Joined
Mar 7, 2024
Posts
89
Reaction score
46
Location
WEEKI WACHEE
Ram Year
2023,2024
Engine
5.7 Hemi
Agreed.

What I'm noticing with the 3.92's is that on the highway I'm not continually shifting in and out of 7th & 8th gears like I did with the 3.21's.

This is a huge bonus for me in terms of driving comfort and reduced wear and tear on my transmission.

I'll gladly sacrifice some fuel for a happier truck. I'm also looking forward to when I put my 35's on soon, too.
What width rims are you thinking about?
 

runamuck

Senior Member
Military
Joined
Sep 4, 2018
Posts
1,729
Reaction score
2,199
Location
dfw
Ram Year
2022
Engine
6.7 dsl
on my '19 laramie 1500 4x4 ccsb hemi 3.92 rear end I usually got around 20 on the highway at 70 typically. 75 or more I would normally get 19. I only burned regular.
 

indept

Senior Member
Joined
Sep 10, 2017
Posts
3,230
Reaction score
4,784
Location
South Jersey
Ram Year
2017
Engine
Hemi 5.7L
2017 1500 CC short bed 4x4 with 3.92's.
I get 17 -19 mpg local ( stop & go 25 - 45 mph)
On level ground going 55 mph I get 24 mpg.
A few years ago we went to Florida & back to NJ, about 2500 miles total. 2200 hwy, rest local and got just over 16 mpg. All highway miles were 70 -85 mph average speed. Mpg was hand calculated. Lie-o-meter read .4 mpg more than hand calc. Lower speed gets better miles / gal, higher speed gets better smiles / skinny pedal push. :D

:cheers:
 

Jeepwalker

Senior Member
Joined
Sep 8, 2017
Posts
3,462
Reaction score
3,767
Location
WI
Ram Year
2012 Reg Cab, 4x4
Engine
5.7 Hemi
You might experience a decrease of 1-2 mpg's when you put the 35's on. Just more rolling resistance. Not against 35's..just sayin. Also depends how/where you drive too. And tire type of course.

Who was it?? Some forum member said they lost 1mpg for every mod they did... lol
 
OP
OP
W

Weekiman

Member
Joined
Mar 7, 2024
Posts
89
Reaction score
46
Location
WEEKI WACHEE
Ram Year
2023,2024
Engine
5.7 Hemi
You might experience a decrease of 1-2 mpg's when you put the 35's on. Just more rolling resistance. Not against 35's..just sayin. Also depends how/where you drive too. And tire type of course.

Who was it?? Some forum member said they lost 1mpg for every mod they did... lol
Good info thanks, yea the wife mentioned 35's. I already have a Chevelle that sucks gas. It's going to be more her truck then mine.
 

Jeepwalker

Senior Member
Joined
Sep 8, 2017
Posts
3,462
Reaction score
3,767
Location
WI
Ram Year
2012 Reg Cab, 4x4
Engine
5.7 Hemi
After a number of 'mods' bumpers/lifts, etc a lot of Ram owners over the yrs have grumbled how they're down to 12-13-14mpg...lol (average ..hand calculated). If/when gas hits $4.50 it's going be a bummer. Hopefully it won't but you know how that goes.

Best to hand-calculate your actual daily aver mpg over a month. The way you/she drives. That gives a better picture. Esp before you do the mods. Then compare afterwards. Well known that the trip computer doesn't always get it right. But at least with 3.92's it won't "kill" your fuel consumption as much as numerically lower gears. And of course, you know..you can (and should) go into the 'computer' and change the truck's tire size to one that better matches your new size after you get them installed.
 
Top