loss of torque...wtf? - Ford Powerstroke Diesel Forum
User Tag List

 
LinkBack Thread Tools Display Modes
post #1 of 7 Old 07-14-2014, 07:59 PM Thread Starter
Member
 
twitchcvma's Avatar
 
Join Date: Oct 2011
Posts: 57
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
loss of torque...wtf?

'97 crew cab, 4wd, 4:10 gears, 168K miles, 3" down pipe
last year I completely gutted my cat. then I got a 4" exhaust from the (gutted) cat back. Nice turbo whistle. tons of low end torque...i thought.
I don't tow much. Sold my big *** boat a couple of years of ago, kept the truck. I had the opportunity to tow about 2K pounds yesterday up and down some 7 and 8 percent grades in the Colorado mountains. In town she runs fine. Very little smoke. She just runs.
Going up the mountains (empty at this time) she was struggling to stay at speed, constantly down shifting, up shifting, then back again. And tons of smoke.
When I hooked up to the trailer and 2 ATV's it got worse. The truck fought even harder to just get going. At one point going up an 8 percent grade, she only managed to hit 45 mph and I was in it. I pushed in the tow/haul button and when she down shifted the EGT's hit 11,000, even more black smoke, and just barely moved. I let off the accelerator til the EGT's backed off. By this time we had crested the top of the pass. Going down hill the EGT's were normal (well, yeah, no load) and going up the next hill I had momentum carrying the truck and trailer so she did OK, but once momentum was gone and I had to accelerate, she lugged hard with a **** ton of black smoke.
Once we were out of the mountains and back on flat ground she did fine. A couple of hills here and there but nothing to speak of.
I noticed a lack of high end torque as soon as i gutted the cat last year. And then a bit more when I got the 4" exhaust. So what happened? Do I need some back pressure? Should I get a performance muffler to add some back pressure? That would be a hell of lot cheaper than a new cat. I really don't want to go back to a cat...unless that is what is needed.
I just want to know what happened and how to correct it. These trucks are capable of towing an incredible amount, but I was having trouble with only about 2000 lb's. Please advise.
Thank y'all so very much
T
twitchcvma is offline  
post #2 of 7 Old 07-14-2014, 08:40 PM
Compression Ignition Addict
 
Join Date: May 2012
Posts: 172
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Thanks: 1
Thanked 5 Times in 5 Posts
Feedback Score: 0 reviews
Sounds like you were not getting any boost. Do you have a boost gauge? Check for exhaust and boost leaks.

1997 Crew Cab Long Bed 4X4 SRW Auto. 280K miles
Stainless Irate Bellowed Up Pipes
Fresh Turbo with 1.0 Housing & Wicked Wheel 2, 3" downpipe with 4" exhaust, Intercooled, 6.0 Fan, 39 gal rear fuel tank + 70 gal Transfer Flow in the bed, Hydroboost, Completely New Suspension (Springs, Shocks, Bushings),Baby Swamps, Hydra Chip with Swamps Tunes, and Swamps IDM,Dually Swap,Tru-Trac locker in the rear

ChallengerRV is offline  
post #3 of 7 Old 07-15-2014, 01:29 AM
DERAIL MOD!!!


 
351fifty's Avatar
 
Join Date: May 2011
Location: Canton and kennesaw
Posts: 23,174
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 34
Thanked 206 Times in 194 Posts
Feedback Score: 4 reviews
^^^ this sounds exactly like your problem, check the impeller wheel too

-Kris-
2011 f150 ecoboost 4x4 323/452 on php dyno 11/16/13
1995 CCLB DRW 324K
2001 CCLB DRW 319K
Dp tuner infinity, exhaust, intake, chipped, tricked, and wrecked


Quote:
Originally Posted by marine5811
The stock downpipe in an OBS is flat because I'm a ginger.
Quote:
Originally Posted by alberta 7.3
Finding a decent woman is like shopping for a used truck. You spend most of your time picking through the money pits, wrecks, and basket cases until you find one that you can tolerate
Quote:
Originally Posted by JJFLASH
Well at least you caught the loose bolts before they cause any damage. Nothing worse than a sloppy hole
351fifty is offline  
post #4 of 7 Old 07-15-2014, 03:53 AM
Compression Ignition Addict
 
Join Date: Nov 2013
Location: Calgary, Ab
Posts: 353
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Thanks: 13
Thanked 29 Times in 29 Posts
Feedback Score: 0 reviews
It's not the cat. I took mine right out 2 weeks ago (no inspection up here) and the change was more, not less power. The factory cats on these trucks are a joke....

Do you have access to a scanner?
Syndicated_cdn is offline  
post #5 of 7 Old 07-15-2014, 03:54 AM
the baconator

 
terryknight's Avatar
 
Join Date: May 2009
Location: Easton MD 21601
Posts: 12,562
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 83 Post(s)
Thanks: 10
Thanked 118 Times in 113 Posts
Feedback Score: 2 reviews
i will third the boost/exhaust leak

94.5 F250 Reg Cab 4x4 5 speed 4.10 276000 plus miles

97 F350 Crew Cab LB 4x4 5 speed 3.55 320000 plus miles (parts truck)



Quote:
Originally Posted by alberta 7.3 View Post
YouTube: Providing idiots everywhere a podium to share their stupidity
terryknight is online now  
post #6 of 7 Old 07-15-2014, 04:58 AM Thread Starter
Member
 
twitchcvma's Avatar
 
Join Date: Oct 2011
Posts: 57
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
I do have a boost gauge. I was so intent on keep my eye on the EGT's I didn't even look at the boost. I thought about that very thing after I got home that night? So having an open exhaust system would not make it harder to pull? It's not back pressure, it may the turbo?
Can I pull a vacuum and check for leaks?
Thanks to all. I really appreciate it
twitchcvma is offline  
post #7 of 7 Old 07-15-2014, 10:28 AM
Compression Ignition Addict
 
Join Date: Feb 2014
Posts: 274
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 0
Thanked 11 Times in 11 Posts
Feedback Score: 0 reviews
Post-turbo back pressure is bad, and will reduce power. You definitely don't need to add more restriction to the exhaust.

It sounds as though you're not getting much boost. There are several common things that can cause this.

- Do a boost leak test. You can get a little adapter gizmo (or make one with some PVC pipe) that goes over the turbo and pressurizes the intake system. Due to sucking oil through the crankcase vent, the various boots tend to get oily and stop sealing. I can almost guarantee you have boost leaks, since that's the default state of these trucks...
- Look for exhaust leaks pre-turbo. Exhaust getting out before the turbo means it won't spin the turbo as fast.
- While you have the boot off for pressurizing the intake system, inspect the turbo compressor wheel. It shouldn't be missing chunks or rounded off.
Syonyk is offline  
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:
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:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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

 
For the best viewing experience please update your browser to Google Chrome