3.55 gears on 37's question - Ford Powerstroke Diesel Forum
6.4L Performance Parts Discussion What has or has not worked for you?

Powerstroke.org is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Like Tree1Likes
Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-24-2014, 03:28 PM
Powerstroke.org Rookie
 

Join Date: Feb 2014
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Question 3.55 gears on 37's question

New to the diesel world and this forum.

I have an '09 FX4 with
* Fab-Tech 6" basic system lift
* Bilstein 5160 on all four corners
* Dick Cepeck 37X12.5X20 Fun Counrty
* H&S Minni Maxx
* Gearhead 6.4 Tune by Matt
* S&B Si stage 2
* 5" Flow-Pro
* 3" Pipe from Intercooler
HP should be about 550 @ the rear wheels and about 1050 ft lb of torque.

I ordered the truck with 3.55 gears when I bought it new along with the 18" wheels.
I have just put on the 37's and Matt re-did my tune for the new tire size.
5TH gear TC will activate at 60 MPH.
@ 65 MPH, RPM's are just over 1500.

With all that said, my hand calculated mileage is 15.5. I thought I would get
a little better fuel mileage. 15.5 is what I was getting with my previous tires which were 35X12.5X20 MT ATZ's.
Before making the leap to a higher gear, I wanted ask for some knowledgeable opinions.
Do I need more HP/Trq to turn the 37's with 3.55's or is 4.10's the way to go.
I'm planning on going with a Jr. High-Power Compounds set turbos from Elite Diesel which is said to make about 700 RW HP with stock injectors and upwards of 800 RW HP with larger nozzles.
Although the 37' look real good with the 6" lift, I may go back down to 35's depending on the research.
What do you think.
Thanks
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 02-24-2014, 04:48 PM
Powerstroke.org Fanatic
 

Join Date: Feb 2010
Posts: 97
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Ive been running the Icon 7" lift with 37's sine day 1 in 09. I put 4.10 gears and never looked back. I don't get very good milaege like 15 highway. I have SCT Offroad tuner w/ dpf delete. Hope that helps. Mine came w/ 17's and 3.23 gears
Reply With Quote Quick reply to this message
  #3  
Old 02-24-2014, 04:57 PM
Compression Ignition Addict
 

Join Date: Sep 2010
Posts: 1,706
Thanks: 1
Thanked 16 Times in 16 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by HotRodDiesel View Post
Ive been running the Icon 7" lift with 37's sine day 1 in 09. I put 4.10 gears and never looked back. I don't get very good milaege like 15 highway. I have SCT Offroad tuner w/ dpf delete. Hope that helps. Mine came w/ 17's and 3.23 gears
3.23????? First I have ever heard of a 6.4 with any lower than 3.55. Even the 6.7s only come down to a 3.31
Reply With Quote Quick reply to this message
  #4  
Old 02-24-2014, 05:36 PM
Powerstroke.org Rookie
 

Join Date: Feb 2014
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
HRD
Thanks for your input.
For what it's worth, my lye-o-meter is kind of accurate. On a tank full of mix
driving, in and around Houston i average 15.5. If I'm on a Beltway trip with over passes
cross town it comes up to about 19.

Should I just be content with that or can it get better?

This is my DD and I keep a light foot 99% of the time.
Reply With Quote Quick reply to this message
  #5  
Old 02-24-2014, 06:59 PM
Compression Ignition Addict
 

Join Date: Sep 2010
Posts: 1,706
Thanks: 1
Thanked 16 Times in 16 Posts
Feedback Score: 0 reviews
I say you should be content with that. I wouldn't do nothing to my truck if it got that kind of fuel mileage. I drove around 300 miles or so the other day and I kept it at around 71mph 3.55s on 35s and averaged around 15.5mpg hand calculated IIRC. Doesn't matter what tune I run whether its from Gearhead or IDP.. I don't even see people on stock size wheels and tires getting the fuel mileage you are claiming much so I would go to sleep and wake up smiling like a jackass if I were you
floorboy likes this.
Reply With Quote Quick reply to this message
  #6  
Old 02-24-2014, 08:01 PM
Powerstroke.org Rookie
 

Join Date: Feb 2014
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
WB
"Thank you Sir...May I have another"...JK

That sound like I'll be saving me some money.
One more question. I was thinking of getting a Detroit Trutrak rear dif installed for stronger and better tracktion control as apposed to my stock Limited Slip.

Yes...No...
Reply With Quote Quick reply to this message
  #7  
Old 02-25-2014, 03:56 AM
Compression Ignition Addict
 

Join Date: Sep 2010
Posts: 1,706
Thanks: 1
Thanked 16 Times in 16 Posts
Feedback Score: 0 reviews
I don't have a Trutrak, but I have seen a lot of guys that are running it that seem happy with it. The factory limited slip sucks to say the least
Reply With Quote Quick reply to this message
  #8  
Old 02-25-2014, 02:59 PM
Powerstroke.org Fanatic
 

Join Date: Feb 2010
Posts: 97
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
oops I was wrong 3.31 was my gear ratio. 2010 6.4 w/ 3.31
Reply With Quote Quick reply to this message
  #9  
Old 02-25-2014, 03:14 PM
Compression Ignition Addict
 

Join Date: Sep 2010
Posts: 1,706
Thanks: 1
Thanked 16 Times in 16 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by HotRodDiesel View Post
oops I was wrong 3.31 was my gear ratio. 2010 6.4 w/ 3.31
Ive never heard of 3.31 in a 6.4..... 3.73 was the lowest offered until 2009 and then the 3.55 became an option for 2009 and 2010
Reply With Quote Quick reply to this message
  #10  
Old 02-25-2014, 04:34 PM
Powerstroke.org Fanatic
 

Join Date: Feb 2013
Location: Merritt BC
Posts: 99
Thanks: 0
Thanked 8 Times in 8 Posts
Feedback Score: 0 reviews
3.55 was standard for 2010, with 3.31 optional. Factory was trying to improve fuel mileage.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Powerstroke Diesel 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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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:

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 -8. The time now is 02:20 PM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.1
Garage Plus, Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

vB.Sponsors