LACK OF TORQUE IN 4TH & 5TH \ TIRE SIZE, GEAR CHANGE? - Ford Powerstroke Diesel Forum
Powerstroke.org is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-14-2011, 03:35 PM
Compression Ignition Addict
 

Join Date: Oct 2010
Location: NC
Posts: 258
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
LACK OF TORQUE IN 4TH & 5TH \ TIRE SIZE, GEAR CHANGE?

I have a 2005 CC F250, 3.73, auto 4x4 and running 34" tires or 275/65R20 and the truck seems to pull really free and easy till around 40 mph or I'm guessing till 4th gear. I have put a tune on it and it is really quick and strong when getting into it but it just seems to be torque less under normal acceleration with or without a load. This is my first diesel truck and I was just expecting it to maintain speed when pulling a hill better than it does. I have a hill that I regularly go up that's probably 1\2 mi at 3-4% grade and running empty it really takes a lot of throttle and many times a down shift to maintain 55mph going up it. My friend had a 2002 7.3 with 3.73 and 35" tires and he drove mine the other day and said it felt totally different than his, claimed it was probably faster off the line but from a roll on at 50 mph he said the 7.3 he had would accelerate quicker and with no down shifts.


Been thinking of going to a 32-33" tire or if within reason changing to 4.10 gears, anyone feel the same about these trucks or played with the tire size and gears?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 02-14-2011, 03:53 PM
Compression Ignition Addict
 

Join Date: Jan 2010
Posts: 256
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
My truck had the same problem. I have a 1000' elevation change in 12 min to do every day on my commute. Some parts are very steep and it seemed like I had to go full throttle just to get up the dam thing doing 80km/h. SCT and custom tunes and now the truck doesn't even shift out of high gear on the steep stuff and I can hold 90 km/h no prob.
My sct x2 used was $100, and three tunes from matt, including SRL which is a great DD was annother $100. Glowshift EGT gauge $100

A heck of a lot cheaper than tires/gears, and way more fun
Reply With Quote Quick reply to this message
  #3  
Old 02-14-2011, 04:17 PM
Compression Ignition Addict
 

Join Date: Oct 2010
Location: NC
Posts: 258
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by HawaiiBake View Post
My truck had the same problem. I have a 1000' elevation change in 12 min to do every day on my commute. Some parts are very steep and it seemed like I had to go full throttle just to get up the dam thing doing 80km/h. SCT and custom tunes and now the truck doesn't even shift out of high gear on the steep stuff and I can hold 90 km/h no prob.
My sct x2 used was $100, and three tunes from matt, including SRL which is a great DD was annother $100. Glowshift EGT gauge $100

A heck of a lot cheaper than tires/gears, and way more fun
I too am running a SCT with the SRL+ tune from Matt and it makes great power but it just feels like the truck doesn't have enough gear to me. If you drive it hard now it will go but I'm looking for it to run a little easier under normal acceleration. When driving easy it will accerlerate up to about 40 mph with little throttle but from there to get it to increase speed your really have to push down on the pedal.
Reply With Quote Quick reply to this message
  #4  
Old 02-14-2011, 04:31 PM
Powerstroke Techie

 

Join Date: Aug 2010
Location: Sassamansville, Pa
Posts: 9,674
Thanks: 86
Thanked 184 Times in 148 Posts
Feedback Score: 3 reviews
You need to find out when the converter locks. Eric's x-street locks the converter after 40mph. And his x-race locks in at 2nd gear.
Reply With Quote Quick reply to this message
  #5  
Old 02-14-2011, 04:44 PM
Compression Ignition Addict
 

Join Date: Jan 2010
Posts: 256
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
My understanding of why these trucks don't seem to perfor well ati higher speeds is the wind resistance becomes a real issue. At higher speeds you utilize the hp morethan the tq. Our trucks tuned dint have any more hp than a dodge hemi pushing a 2000lb lighter truck
Reply With Quote Quick reply to this message
  #6  
Old 02-14-2011, 04:45 PM
Compression Ignition Addict
 

Join Date: Oct 2010
Location: NC
Posts: 258
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by Lilpooh View Post
You need to find out when the converter locks. Eric's x-street locks the converter after 40mph. And his x-race locks in at 2nd gear.
I guess when the converter locks up then you would have to give it more throttle to accelerate as the RPM's would drop off along with the torque, am I on the right train of thought?
Reply With Quote Quick reply to this message
  #7  
Old 02-14-2011, 05:04 PM
Compression Ignition Addict
 

Join Date: Oct 2010
Location: NC
Posts: 258
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
I think ideally lowering the 4th and 5th gear ratios in the transmission would be great but I don't think that would be very cost effective

I was pulling a tractor on trailer combo weighing around 10K the other day and it gets that load moving fairly easy, with little throttle input, up to 35-40mph but after that I really had to give it the throttle to get an increase in speed form there, makes me worry a little about taking a trip to the mountains with a 6K load, I'll probably get about the same MPG as I did driving my friends Chevy 6.0L gasser, 7.6MPG
Reply With Quote Quick reply to this message
  #8  
Old 02-14-2011, 05:09 PM
Compression Ignition Addict
 

Join Date: Nov 2008
Location: California
Posts: 4,260
Thanks: 0
Thanked 1 Time in 1 Post
Feedback Score: 0 reviews
Some people(not me) increase the rpm limit so that when the truck shifts, there will not be as much power loss because the drop in rpms are not at the lower levels.
Reply With Quote Quick reply to this message
  #9  
Old 02-14-2011, 05:15 PM
Powerstroke.org Fanatic
 

Join Date: May 2010
Posts: 126
Thanks: 0
Thanked 1 Time in 1 Post
Feedback Score: 0 reviews
I am in the same boat 35" tires with 3:73 gears and its tuned and runs great up to about45/ 50 mph after that its all down hill. We need gears I am thinking around 4:88's to 5:13's just look at your RPM's when your cruising at 55 mph you should be at about 2100 RPM's but I am sure you are at about 1600 to 1800 RPM's
Reply With Quote Quick reply to this message
  #10  
Old 02-14-2011, 05:20 PM
Compression Ignition Addict
 

Join Date: Oct 2010
Location: NC
Posts: 258
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by smokersteve View Post
Some people(not me) increase the rpm limit so that when the truck shifts, there will not be as much power loss because the drop in rpms are not at the lower levels.
I just sent Gearhead an e-mail and maybe there can be a little tuning to improve this but I think there could be a better gearing setup to make these trucks run a little freeier without having to throw more fuel to it, talking normal acceleration here, sometime more fuel is fun but that's reducing with this $3.55\gal fuel
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 01:29 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