Sponsored

Gear Ratio Swaps

mpeugeot

Outer Banks
Well-Known Member
First Name
Mark
Joined
May 14, 2021
Threads
18
Messages
7,409
Reaction score
13,792
Location
Texas
Vehicle(s)
97 Ferrari F355, 11 Ford F-150, 21 OBX 2D
Your Bronco Model
Outer Banks
Actually the number 1 factor in fuel economy in any vehicle is the driver, I say that as a 35+ year professional driver. But yes the auto in the Bronco has plenty of overdrive to maximize economy. I can also say the Bronco would do better in a wind tunnel test than you might think based on it's looks. Square lines don't always mean poor aerodynamics and round lines don't always mean good aerodynamics.
I thought about making an easy to remove air-dam to see if it would improve mileage.
Sponsored

 

1970AMCAMX

Base
Well-Known Member
First Name
Robert
Joined
Jul 22, 2021
Threads
17
Messages
739
Reaction score
1,665
Location
Titusville, FL
Vehicle(s)
F150, AMC AMX, DF Goblin
Your Bronco Model
Base
If you really want to change the gears and are mechanically inclined, I recommend offering to swap someone that has an automatic bronco with 3.73 gears. I'm sure you could find someone that would trade front and rear axles with you.

I would bet that your mileage will not be any better and may even be worse after the change.
 

okbob

Badlands
Well-Known Member
Joined
Feb 25, 2016
Threads
9
Messages
1,443
Reaction score
3,186
Location
North of the Red
Vehicle(s)
71' u15, 66' u14, 66' u14
Your Bronco Model
Badlands
Clubs
 
It would take you a considerable amount of time and fuel to pay off the cost of the swap, and there's no guarantee that your milage would increase that much. Our 2D Badlands with Sasq is getting 18.7-20.4 highway in eco mode unless we're into a head wind.
 

BigMeatsBronco

First Edition
Well-Known Member
Base Sponsor (Level 1)
First Name
Allan
Joined
Nov 25, 2021
Threads
38
Messages
2,360
Reaction score
6,669
Location
97301
Vehicle(s)
2021 FE 2 door
Your Bronco Model
First Edition
Clubs
 
Actually the number 1 factor in fuel economy in any vehicle is the driver, I say that as a 35+ year professional driver. But yes the auto in the Bronco has plenty of overdrive to maximize economy. I can also say the Bronco would do better in a wind tunnel test than you might think based on it's looks. Square lines don't always mean poor aerodynamics and round lines don't always mean good aerodynamics.
I agree, most people don't realize the ass end of the Bronco is nearly 3" narrower than the front!!! This alone makes a huge aerodynamic improvement.
 

gryphon1231

Well-Known Member
First Name
dj
Joined
Jul 14, 2020
Threads
4
Messages
1,288
Reaction score
2,017
Location
Miami FL
Vehicle(s)
na
Your Bronco Model
Undecided
Clubs
 
So waiting for my new Bronco as we’ve all experienced and fuel prices climbing we begin to think about the choices we’ve made. Now I wont be driving my Bronco every day but often enough that Ive wondered how to improve its fuel economy already. My daily commute is 110 miles and heavy traffic. So I try to ride my motorcycles when weather permits. First I ordered the BD because it does come with a somewhat narrower tire. But the gearing is 4:46 I wonder how much trouble it would be to go to 3:55s but mostly how that would work for the front differential… And in the long run would you be better off doing a gear vendors overdrive setup…. Anyone swap gears yet in these?
You'd probably break even if you're lucky. Especially if ride your motorcycles most of the time

Looking down the road it will probably lower the trade in value as well.
 

Sponsored

HoosierDaddy

Badlands
Well-Known Member
First Name
Eric
Joined
Mar 6, 2016
Threads
37
Messages
5,421
Reaction score
13,848
Location
Indiana
Vehicle(s)
68&69 Broncos, 21 AMB Base 2dr, 23 VB BL 4dr
Your Bronco Model
Badlands
Clubs
 
It's funny how many people do not trust the Ford engineers to get the gearing right.

Even though the Bronco gets pretty good mileage for what it is, if you run the numbers, you may still be able to make a high MPG car pay for itself if you have a big commute.
I've done that in the past. I bought a used Outback , made the payment, fueled it, etc etc for less money monthly than the F250 (paid off) was using in fuel each month.

I tend to work at or travel through areas that are very rough on vehicles, so another thing I learned was how nice it was to drive a car that you did not care about at all ... no more worries about door dings , rock chips, whether it is clean enough or not ... etc etc
The one you worried about was at home in the garage.
If I worked overtime on the weekends, I'd treat myself by taking the truck to work those days.
It worked for me.
 

mpeugeot

Outer Banks
Well-Known Member
First Name
Mark
Joined
May 14, 2021
Threads
18
Messages
7,409
Reaction score
13,792
Location
Texas
Vehicle(s)
97 Ferrari F355, 11 Ford F-150, 21 OBX 2D
Your Bronco Model
Outer Banks
At the end of the day, all of the locking rear Broncos and the base have essentially the same overall gearing when you include wheels and tires. What is interesting is that the 2.3 and 2.7 have the same gearing.
 

HoosierDaddy

Badlands
Well-Known Member
First Name
Eric
Joined
Mar 6, 2016
Threads
37
Messages
5,421
Reaction score
13,848
Location
Indiana
Vehicle(s)
68&69 Broncos, 21 AMB Base 2dr, 23 VB BL 4dr
Your Bronco Model
Badlands
Clubs
 
What is interesting is that the 2.3 and 2.7 have the same gearing.
Shooting for the same power band rpm wise ... one just measures higher on the charts!! LOL

Also interesting that the test drivers, even the ones not on Fords payroll, do not mark a big difference between the two, When offroad said they couldn't really tell the difference.
 

ctandc

Big Bend
Well-Known Member
Joined
Dec 2, 2021
Threads
12
Messages
470
Reaction score
876
Location
VA
Vehicle(s)
'22/23 Bronco, 96 EB Bronco
Your Bronco Model
Big Bend
Clubs
 
The rear gear swap wouldn’t be bad, if you can do it yourself or at least remove the rear axle assm and take it to someone. Odds are you would need to make changes via FORSCAN for the new ratio. $700-900 in parts. Thing is you can buy the complete rear axle assm, ready to bolt in for $2k. Or score one from a wrecked Ranger. Replacement front diff assm’s are already out there.
Thing is? I doubt you’d Really gain any appreciable difference in MPG.

For the money, you’d be better off buying lighter aftermarket wheels to go with a smaller tire with less of an AT or MT tread.

I am sure Ford engineers spent a ton of time working on the Bronco’s aerodynamics to eek out more efficiency, but it was always going to be a retro type (boxy) vehicle.

Alot of people seem totally focused with RPM when talking about fuel efficiency, but I have noticed that when running ECO or normal at highway cruising speeds, using cruise control, the engine tends to go into boost alot more than when using Sport. mode.
 

mpeugeot

Outer Banks
Well-Known Member
First Name
Mark
Joined
May 14, 2021
Threads
18
Messages
7,409
Reaction score
13,792
Location
Texas
Vehicle(s)
97 Ferrari F355, 11 Ford F-150, 21 OBX 2D
Your Bronco Model
Outer Banks
The rear gear swap wouldn’t be bad, if you can do it yourself or at least remove the rear axle assm and take it to someone. Odds are you would need to make changes via FORSCAN for the new ratio. $700-900 in parts. Thing is you can buy the complete rear axle assm, ready to bolt in for $2k. Or score one from a wrecked Ranger. Replacement front diff assm’s are already out there.
Thing is? I doubt you’d Really gain any appreciable difference in MPG.

For the money, you’d be better off buying lighter aftermarket wheels to go with a smaller tire with less of an AT or MT tread.

I am sure Ford engineers spent a ton of time working on the Bronco’s aerodynamics to eek out more efficiency, but it was always going to be a retro type (boxy) vehicle.

Alot of people seem totally focused with RPM when talking about fuel efficiency, but I have noticed that when running ECO or normal at highway cruising speeds, using cruise control, the engine tends to go into boost alot more than when using Sport. mode.
I have tried to game the RPM vs boost with regards to fuel economy, but without significant results so far. While sport mode tends to accelerate a little more assertively than eco or normal, I have yet to see substantial differences in highway mileage. As a result, I just run it in sport mode 4A all the time. I would be interesting to see what happened if I did 50 miles in 2H Baja mode for laughs.

I wonder how that might affect mileage. 4L in Baja on the beach is just a blast, it's just straining to be unleashed.
 

Sponsored

ctandc

Big Bend
Well-Known Member
Joined
Dec 2, 2021
Threads
12
Messages
470
Reaction score
876
Location
VA
Vehicle(s)
'22/23 Bronco, 96 EB Bronco
Your Bronco Model
Big Bend
Clubs
 
I have tried to game the RPM vs boost with regards to fuel economy, but without significant results so far. While sport mode tends to accelerate a little more assertively than eco or normal, I have yet to see substantial differences in highway mileage. As a result, I just run it in sport mode 4A all the time. I would be interesting to see what happened if I did 50 miles in 2H Baja mode for laughs.

I wonder how that might affect mileage. 4L in Baja on the beach is just a blast, it's just straining to be unleashed.

Yeah, it's likely negligible either way over normal driving, but I noticed a difference on a decent highway stretch. We're heading on a 350 mile each way road trip hopefully in June. I'm going to give it a go then and see what happens.

In all honesty, Sport in 2H is so much more enjoyable in everyday driving, I personally wouldn't care if it cost me a bit in gas.
 

Snacktime

Black Diamond
Well-Known Member
First Name
Nate
Joined
Jul 14, 2020
Threads
54
Messages
2,690
Reaction score
5,845
Location
Sac-a-tomatoes
Vehicle(s)
Bronco, F150
Your Bronco Model
Black Diamond
Clubs
 
I feel like I get the most MPG at 2-3psi of boost. I have played with manual mode on the freeway with cruse control. People tend to forget that a turbo generates increase in efficiency so you have to run some boost to see the benefit. Best way would be to monitor the duty cycle on the injectors vs boost/rpm.

I do believe the 2.3 is happier with higher cruse rpms.
 

JT58Bronc

Base
Well-Known Member
First Name
JT
Joined
Jul 14, 2020
Threads
18
Messages
1,196
Reaction score
1,468
Location
Fl
Vehicle(s)
2022 Bronco, 2021 Miata track Edition
Your Bronco Model
Base
4WD vehicles like Jeeps and Broncos will never get really good fuel economy. Gearing is important so that you have the right gears with the tire size of your choice or your fuel economy will suffer even more. Better to order and get the gears/tire size you want from the factory.

I hear ya on the fuel economy thing. Gas just keeps going up and there's no end in sight. I remember driving my 70's Broncos and my 79 CJ5 everywhere and anywhere. Gas was so cheap back then- never a concern for cost of gas- you just put it in- even when I worked only part time and was in college. My wife and I love our Sas Bronco and have to split the gas bill to drive it on weekends. I can't afford to drive it to work with my 90 mile round trip per day so unfortunately it just sits in the garage. I have to drive my 53 MPG Jetta. 2 months and only 600 miles on the Sas. It is what it is.....
Sponsored

 
 


Top