Shorter final drive swap for better MPG? - Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum
Ford Focus Forum
HomeContact UsAbout UsGalleryDiscussion ForumsMarketplace


Go Back   Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum > Ford Focus Tech Discussions > Engine & Transmission Swap

Engine & Transmission Swap The place to chat about any engine and transmission swap.

Search This Forum | Image Search | Advanced Search    
FocusFest FocusFanatics Merchandise

Reply
 
LinkBack Thread Tools Display Modes
Old 06-03-2011, 01:29 PM   #1
Focus Addict
 
Join Date: Jan 2006
Fan#: 31234
Location: Fowlerville, MI
What I Drive: 2006 Silver ST w/SAP#1

Posts: 1,079
Points 2,855, Level 32
Points: 2,855, Level: 32 Points: 2,855, Level: 32 Points: 2,855, Level: 32
Level Up 70% Completed
Level up: 70% Level up: 70% Level up: 70%
Forum Activity 1%
Activity: 1% Activity: 1% Activity: 1%
FF Reputation: 14 gokart2 Great Standing Member
Buy-Sell-Trade Rating: (0)
Shorter final drive swap for better MPG?

Anyone swap out the 3.8 final for the older, shorter one (cant remember the size) for better highway fuel economy? If so, what was the gain. I have it calculated to drop ~ 325 rpm @ 80mph, so I'd assume maybe 3 mpg gain? I don't know. I'm getting avg 30 mpg right now on mainly highway driving. The only reason I'm considering it is cause I drive roughly 650 miles per week. Just curious to see who's done it and what the gain was. Basically if it's worth it. I'm wanting an LSD as well for the lovely Michigan winters, figured I'd do it all.


__________________
ST Crew #90
My wife---><----Me
gokart2 is offline  
    Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 06-07-2011, 01:39 AM   #2
Focus Enthusiast
 
Join Date: Mar 2011
Fan#: 84300
Location: Canton, MI
What I Drive: 2011 Ford Focus SES

Posts: 430
Points 463, Level 9
Points: 463, Level: 9 Points: 463, Level: 9 Points: 463, Level: 9
Level Up 26% Completed
Level up: 26% Level up: 26% Level up: 26%
Forum Activity 2%
Activity: 2% Activity: 2% Activity: 2%
FF Reputation: 1 Outlaw5.0 Good Standing Member
Buy-Sell-Trade Rating: (0)
Shorter means more gear, as in from 3.73 to 4.10

Taller means less gear, as in from 4.10 to 3.73.

Yes less gear will usually result in increased fuel mileage, but the speedo will need to be recalibrated. Also its possible the processor may need some changes for shift points depending on if it goes off of mph or rpm.
Outlaw5.0 is offline  
    Reply With Quote Quick reply to this message
Old 06-07-2011, 08:36 AM   #3
br/o/stang
 
Buickboy's Avatar
 
Join Date: Oct 2005
Fan#: 28542
Location: Stratford, CT
What I Drive: '95 Neeeeon, '12 Mustang

Posts: 5,314
Points 28,754, Level 99
Points: 28,754, Level: 99 Points: 28,754, Level: 99 Points: 28,754, Level: 99
Level Up 25% Completed
Level up: 25% Level up: 25% Level up: 25%
Forum Activity 9%
Activity: 9% Activity: 9% Activity: 9%
FF Reputation: 39 Buickboy Great Standing Member
Buy-Sell-Trade Rating: (29)
03-04 2.3l cars had a 3.42 final, which id imagine would do something but I havent heard of anyone going down, only up to a 3.82 or 4.06
__________________
==2012 Kona Blue Mustang V6==
==1995 Light Iris Neon Coupe==
Sold but not forgotten: 2001 ZX3, 2007 ZX3, 1972 Skylark
Buickboy is online now  
    Reply With Quote Quick reply to this message
Old 06-07-2011, 09:06 AM   #4
un1corn
 
ehancock's Avatar
 
Join Date: Feb 2008
Fan#: 53353
Location: Farmington Hills, MI, MI
What I Drive: 2004 Twilight Blue D23 ZX5

Posts: 2,703
FF Reputation: 14 ehancock Great Standing Member
Buy-Sell-Trade Rating: (7)
I swapped out my 3.42(1?) for a 3.82 right before driving to Florida last year and I honestly didn't really notice any difference in my gas mileage. I know that I should have seen some decrease in gas mileage but if it's there it's not very noticeable. My point is that there should be a gain in mpg but probably not a lot. Unless you do the labor yourself I think by the time you source the taller final drive and swap it in it's not going to be worth it from a $$ point of view. It would take a long time to make up that amount of money in mpg savings. That and the pzev gears are loooooooong.
ehancock is offline  
    Reply With Quote Quick reply to this message
Old 06-07-2011, 06:18 PM   #5
br/o/stang
 
Buickboy's Avatar
 
Join Date: Oct 2005
Fan#: 28542
Location: Stratford, CT
What I Drive: '95 Neeeeon, '12 Mustang

Posts: 5,314
Points 28,754, Level 99
Points: 28,754, Level: 99 Points: 28,754, Level: 99 Points: 28,754, Level: 99
Level Up 25% Completed
Level up: 25% Level up: 25% Level up: 25%
Forum Activity 9%
Activity: 9% Activity: 9% Activity: 9%
FF Reputation: 39 Buickboy Great Standing Member
Buy-Sell-Trade Rating: (29)
Probably is a 3.41, my bad.
__________________
==2012 Kona Blue Mustang V6==
==1995 Light Iris Neon Coupe==
Sold but not forgotten: 2001 ZX3, 2007 ZX3, 1972 Skylark
Buickboy is online now  
    Reply With Quote Quick reply to this message
Old 06-08-2011, 07:41 PM   #6
Focus Addict
 
Join Date: Jan 2006
Fan#: 31234
Location: Fowlerville, MI
What I Drive: 2006 Silver ST w/SAP#1

Posts: 1,079
Points 2,855, Level 32
Points: 2,855, Level: 32 Points: 2,855, Level: 32 Points: 2,855, Level: 32
Level Up 70% Completed
Level up: 70% Level up: 70% Level up: 70%
Forum Activity 1%
Activity: 1% Activity: 1% Activity: 1%
FF Reputation: 14 gokart2 Great Standing Member
Buy-Sell-Trade Rating: (0)
I have a manual trans and a xcal3 so programmings no problem. I would do it myself. I calculate my mpg everytime I fill up, and at three times a week for that matter. IDK, like I said.... I calculated it out to roughly 325rpm difference. So that comes out to roughly 97500 rpm's a week my car won't have to spin, hence less fuel used. I'm sure u didnt notice a mpg difference because ur not driving 1 million miles a week, and checking ur mpg every 15min.
__________________
ST Crew #90
My wife---><----Me
gokart2 is offline  
    Reply With Quote Quick reply to this message
Reply

Bookmarks & Social Networks

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
What I Drive
Year, color, and model of your car. Example: 2003 Pitch Black ZX3
Name
Your real name.
City
State
Country
Insurance
Please select your insurance company (Optional)

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 09:11 PM.


Copyright 2002-2015 FocusFanatics.com. All Rights Reserved : Privacy Policy : Advertise Information

Focus Fanatics Ford Focus Forum offers many fun ways for you to engage with other Ford Focus Owners from across the world. Whether it be about the aftermarket performance modifications, technical how-to's, European tuned suspension or awesome fuel economy similar to the Mazda CX-3, Audi S3, Mazda MX-5 Miata and Acura TLX. You can find all Ford Focus, Focus ST and Focus RS related information here. Join our Ford Focus discussion forums and chat with local Focus enthusiasts in your area. If you own other makes have a look at Challenger Hellcat Forum, Charger Hellcat Forum, Cadillac ATS-V Forum, Cadillac ATS Forum, Cadillac CTS-V Forum, Lexus RC-F Forum, Lexus GS-F Forum, Mercedes GLA Forum, Mercedes GLE Forum, Civic Type-R Forum and Volvo XC90 Forum.





Search Engine Optimization by vBSEO 3.6.1