Results 1 to 9 of 9

Thread: Need an opinion and help on the pressures/ slip of new tranny. Files attached

  1. #1
    New Member mjmenke1's Avatar
    Join Date
    Jan 2016
    Posts
    9

    Default Need an opinion and help on the pressures/ slip of new tranny. Files attached

    I'm in the process of learning tranny tuning. I've just installed a new completely built 4l65 in my car and attached is my first log driving it along with the tune. I'm confused about some of the data. How do Input shaft revolution and output shaft revolution work, mine seem to differ in the 1100 at WOT in second and showing 175 to 200 TCC Slip @ 5500 rpm. Is the offset in input to output the gearing difference for 2nd?

    I believe I've read < 10% slip is good? Is that a good figure to use?

    The highest I see my Pressure Control Solenoid Pressure go to is 90 psi I thought it could go to 96 psi. Do I have something adjusted wrong in the tune?

    Is there a PID or way to Log Line Pressure can't seem to find that.

    The car has been scaled 20% to stay under the g/sec limit. I understand this can mess with the torque calculations for tranny pressure.

    The log shows a short WOT run at 360 and a longer one at 5400

    Thanks for the help
    Attached Files Attached Files

  2. #2
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    TCC slip depends on when the TCC is locked.

    TIS/TOS will have a different ratio depending on the current gear.


    We need to see these pids:
    GM.TCCMODE
    GM.GEAR

    Also, add this pid:
    GM.SHIFTLAST

    You can then drop these pids:
    GM.SHIFT12
    GM.SHIFT23
    GM.SHIFT34
    GM.TCMSLIP <--- ( keep GM.TCCSLIP )
    GM.TFMCUR
    GM.TFMDES
    Last edited by joecar; May 1st, 2017 at 12:43 PM.

  3. #3
    New Member mjmenke1's Avatar
    Join Date
    Jan 2016
    Posts
    9

    Default

    Thanks for the help, I'm going to the track this weekend and will add the PIDs you suggested. I'll follow up with some logs.

  4. #4
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Try those pids on the street first, before you go to the track.

    ~ posted by phone ~

  5. #5
    New Member mjmenke1's Avatar
    Join Date
    Jan 2016
    Posts
    9

    Default

    At the 1/2 mile race this past weekend I made a few runs with my converter unlocked and 1 locking it in 4th at 150. MPH were about 3-4 higher unlocked in the 1/2, I can't attribute that necessarily to the locking because my 1/4 mph was slower on the locked run by about 4 mph (the 150 lock speed came after the 1/4 distance) and I played with tire pressure and timing a few degrees each run.

    Locking the converter did take my rpm from about 5750 down to about 4750. That caused my MAP to go from 219 kpa to 182 kpa or I lost about 5lbs of boost as soon as it locked. From what I see in the log, the converter locked solid right away.

    I did not try locking it again after looking at the boost I lost given I had limited runs. I would have liked to try locking in 3rd and 4th, maybe next race. I was concerned about the shift from 3rd to 4th being locked, I don't know enough about tranny tuning to be certain how that would work, is there enough time to unlock before it shifts to 4th...

    I have attached logs of 3 runs, Inputs and thoughts appreciated.


    180.7229 half 145.8198 qtr 1 run.efi

    These 2 were back to back
    173.3436 half 142.9479 qtr run 5.efi
    Locked Converter 169.6833 half 138.8032 qtr run 4.efi

  6. #6
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Torque converters have the attribute that when they slip they multiply the torque going in (so the torque coming out is greater!) and they let the engine spin at a higher rpm (so that it runs closer to peak torque)... so basically at the dragstrip you can do better with the TC unlocked.

  7. #7
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    BTW: If you're tuning with two widebands, I can setup a pid to dynamically select the leanest bank (i.e. so your BEN correction will be for the leanest bank).



    If you edited your calc_pids.txt post it here so I can add that.
    Last edited by joecar; May 11th, 2017 at 11:41 AM.

  8. #8
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Ok, on your next runs, I want to increase the scantool's frame rate (i.e. keep pid channel count to 24 or less) because I want to see in more detail some of the waveform changes...

    so drop these pids:
    - GM.FTC
    - GM.TFMDC
    - GM.IAC
    - GM.TRQENG
    - GM.TRQTRANS

  9. #9
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Those are good logs, they show the TC couples nicely (i.e. while it is unlocked) and they show it locking solidly (as you said).


    Click image for larger version. 

Name:	000036.png 
Views:	240 
Size:	143.6 KB 
ID:	21063
    Click image for larger version. 

Name:	000037.png 
Views:	229 
Size:	144.3 KB 
ID:	21064
    Click image for larger version. 

Name:	000038.png 
Views:	233 
Size:	143.9 KB 
ID:	21065

Similar Threads

  1. Opinion
    By Gwoody in forum Cummins 5.9L
    Replies: 6
    Last Post: April 23rd, 2015, 10:47 PM
  2. Replies: 13
    Last Post: February 19th, 2014, 05:03 PM
  3. Problem with my Head/Cam 98 LS1 camaro - files attached
    By blackflag in forum Gen III V8 Specific
    Replies: 157
    Last Post: May 10th, 2011, 04:27 PM
  4. BIG Auto VE problem - Tune files attached
    By Kevin Doe in forum General (Petrol, Gas, Ethanol)
    Replies: 15
    Last Post: October 14th, 2007, 01:57 PM
  5. Need the opinion of others ;)
    By Tordne in forum General (Petrol, Gas, Ethanol)
    Replies: 14
    Last Post: April 19th, 2006, 07:01 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •