Page 1 of 2 12 LastLast
Results 1 to 20 of 25

Thread: 6R80 6F55 - Over-revving / commanded shift points??

  1. #1
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772

    6R80 6F55 - Over-revving / commanded shift points??

    Anyone else with a 6R80 or 6F55 from a 2015-up notice that the WOT tables don't really do anything? For example, in the two WOT tables, I have the 1-2 and 2-3 set for 6250 RPM. I adjust the Base / Sport shift schedules so the OSS at WOT pedals corresponds to the right engine RPM. However, during actual WOT shifting, it either bangs against the revlimiter or hangs at around 6500+ RPM. So I dropped the OSS for 1-2 and 2-3 down to values that correspond to about 5900 RPM and the 1-2 is now much better but the 2-3 still hangs at 6500 RPM. My first guess is that the 1-2 and 2-3 rev up higher than expected due to not having the TC locked up causing it to spin up too fast for the commanded shift point? I first noticed this awhile ago when I used the factory settings for this N/A 3.5 engine (6750 RPM commanded, 7100 RPM stock revlimiter) and saw the WOT 1-2 and 2-3 consistently bang against the 7100 RPM limiter and hang for about 1 second. Keep in mind this is straight from the factory.

  2. #2
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    755
    WOT shift tables works as advertised but they need to be adjusted correctly.

    It all depend on what you have in your OSS shift schedule.
    Last edited by veeefour; 1 Week Ago at 12:25 PM.

  3. #3
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772
    In my 2014 SHO, I never touched the OSS shift schedule and adjusted the WOT tables with success. On the newer vehicles, even ones with the same trans and ECU, how would you define correctly adjusting the WOT tables? I set them to 6250 RPM and it is shifting at 6500 RPM, even when the OSS tables are adjusted accordingly. I'm thinking the newer TCMs behave differently?

    I had to back down the OSS tables by like 400 RPM+ versus where it should have been, and still need to drop it for the 2-3

  4. #4
    Tuner JaegerWrenching's Avatar
    Join Date
    Jun 2018
    Location
    Albuquerque New Mexico
    Posts
    138
    Quote Originally Posted by metroplex View Post
    Anyone else with a 6R80 or 6F55 from a 2015-up notice that the WOT tables don't really do anything? For example, in the two WOT tables, I have the 1-2 and 2-3 set for 6250 RPM. I adjust the Base / Sport shift schedules so the OSS at WOT pedals corresponds to the right engine RPM. However, during actual WOT shifting, it either bangs against the revlimiter or hangs at around 6500+ RPM. So I dropped the OSS for 1-2 and 2-3 down to values that correspond to about 5900 RPM and the 1-2 is now much better but the 2-3 still hangs at 6500 RPM. My first guess is that the 1-2 and 2-3 rev up higher than expected due to not having the TC locked up causing it to spin up too fast for the commanded shift point? I first noticed this awhile ago when I used the factory settings for this N/A 3.5 engine (6750 RPM commanded, 7100 RPM stock revlimiter) and saw the WOT 1-2 and 2-3 consistently bang against the 7100 RPM limiter and hang for about 1 second. Keep in mind this is straight from the factory.
    I have this same issue on my 2018 f250 with a 6r140, I can't log the required tables to know if my changes are doing as intended because the 6r140 is not nearly as supported as the 6r80... and i haven't spent any time on anything besides a 6r140 so i don't have prior knowledge to use on this trans. So far I think it has more to do with line pressure and clutch fill times than anything else. I think you should set your OSS tables correctly, then start to mess with increasing line pressure sooner. Then play with dialing in clutch fill times until it's shifting as desired. This generates quicker shifts as well, which is something i saw you were interested in a while back. Can you post your file so i can see what it looks like?

  5. #5
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    755
    A lot of things can slow the WOT response, over shoot or short shift - tip in logic is a PITA for example.

    WOT table has to be adjusted to OSS - one will not work without another. RPM anticipation plays a role as well.

    TCC schedule is also very important - again has to be adjusted correctly. Also how fast TCC locks since there will be no time to complete the sift with TCC being modulated

    Nothing easy in those tunes hence some tuners charging 300-ish for locked tunes and won't send you any unlocked tunes even for 5 grand.

    Took me moths to figure it out. Shifting at 8300:
    https://www.youtube.com/watch?v=ItQWB95lh6M

    Shifting at 7800:
    https://www.facebook.com/veee.perfor...1573562899618/

  6. #6
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772
    Well the SHO just needed a bit more pressure and that was it. WOT tables alone controlled the shift points.

    I can see the over Rev from 1 to 2 because there is no TCC lockup. But 2 to 3 should have the TCC lockup. The 3-4 is almost always fine except on the Explorer which over rwvvs and bangs the limiter from the factory. Ford didn't even have the right shift schedule programmed for 2016 and newer and even on the Police Interceptors.

    The newer cars shifted improperly straight from the factory. Over revving and banging against the limiter at WOT straight from the factory. I managed to get the same trans in the Fusion Sport to do what I wanted. But now on a lower performance vehicle it over revs. I used the same pressure and clutch fill times to no avail. Making the OSS values lower seemed to work on this vehicle. Factory shifting was 6750 RPM but I actually want it lower. What's frustrating is that the same transmissions are reacting very differently. No rhyme or reason.

  7. #7
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    755
    Try to play with converter lock-up rate for example and see if WOT shits are affected by any means.

  8. #8
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772
    I've done that and it works fine for the higher gears where the rev up isn't as fast. I'm not sure if the TCC is locking up as quickly for 2nd gear since the gear ratio is fairly tall.

  9. #9
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    755
    1-2 shift will always short shift - as mentioned it's due the nature of unlocked TCC plus tall 1st gear ratio. There are ways to fix this.

  10. #10
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772
    I wanted that type of shifting. It's not short shifting as it is finally doing it at the RPM I want. It's the 2-3 hang and bang into the limiter that I am trying to eliminate.

  11. #11
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    755
    Quote Originally Posted by metroplex View Post
    I wanted that type of shifting. It's not short shifting as it is finally doing it at the RPM I want. It's the 2-3 hang and bang into the limiter that I am trying to eliminate.
    Increase clutch fill time and report back.

  12. #12

  13. #13
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772
    I'm out of town so I can't post the stock tune. But everything I've read and heard indicates that the clutch fill times aren't what you really want to command, but rather the actual/approximate fill times for the clutch. I did read that huge 6R80 guide on this forum and experimented with decent results on the Fusion Sport - but these were ineffective on the 2018 Explorer XLT N/A 3.5. I remember playing with them (increasing them, lowering them) with zero effect on the newer 6F55. Stock WOT tables are set for 6750 RPM for 1-2, 2-3, and 3-4. Actual shift RPMs were something like 7100 RPM (the stock revlimiter) for WOT 1-2 and 2-3, but they were sloppy - banging against the revlimiter with a lot of lurch/delay before engaging the next gear. I understand that 2-3 and beyond are clutch-clutch. I was finally able to get WOT 1-2 down to what I wanted by lowering the OSS tables lower than what I estimated (I have a spreadsheet that plots the shift points/RPMs/OSS by gear). Increasing oncoming/offgoing shift pressure helped a lot on one application, but not so much on this one. For my 2014 SHO, all I did was adjust the WOT tables and never ever touched the OSS tables. I even tried copying the 2014 SHO settings over to the newer 6F55s and it made zero difference.

    I will look at clutch fill time again once I get back, but I have a feeling I'll end up lowering OSS tables even more to get the right shift point. The WOT tables were ineffective on this application, basically dummy values that the ECU/TCM ignores on these vehicles.
    Last edited by metroplex; 1 Week Ago at 12:45 PM.

  14. #14
    Tuner JaegerWrenching's Avatar
    Join Date
    Jun 2018
    Location
    Albuquerque New Mexico
    Posts
    138
    Quote Originally Posted by veeefour View Post
    A lot of things can slow the WOT response, over shoot or short shift - tip in logic is a PITA for example.

    WOT table has to be adjusted to OSS - one will not work without another. RPM anticipation plays a role as well.

    TCC schedule is also very important - again has to be adjusted correctly. Also how fast TCC locks since there will be no time to complete the sift with TCC being modulated

    Nothing easy in those tunes hence some tuners charging 300-ish for locked tunes and won't send you any unlocked tunes even for 5 grand.

    Took me moths to figure it out. Shifting at 8300:
    https://www.youtube.com/watch?v=ItQWB95lh6M

    Shifting at 7800:
    https://www.facebook.com/veee.perfor...1573562899618/
    In these videos do you have torque reduction enabled still but set to a torque limit it won't reach or do you have it disabled?Torque Reduction.PNG

  15. #15
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    755
    Quote Originally Posted by JaegerWrenching View Post
    In these videos do you have torque reduction enabled still but set to a torque limit it won't reach or do you have it disabled?Torque Reduction.PNG
    I never disable torque reductions. Spark cut is present in those shifts.

  16. #16
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772
    Cool vids, seems like normal shifting to me. That's how my SHO shifted from the factory. But not how the newer 6F55s shift straight from the factory. I'll get a chance to tweak it some more tomorrow.

    For the OSS tables, is the output shaft speed the Engine RPM divided by gear ratio?

  17. #17
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    755
    Quote Originally Posted by metroplex View Post
    For the OSS tables, is the output shaft speed the Engine RPM divided by gear ratio?
    Nope, RPM is not taken into consideration besides anticipation logic.

    OSS = turbine speed(ISS-inpust speed shaft)/gear ratio

  18. #18
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772
    Is that turbine speed multiplied by input shaft speed in your above formula?
    Last edited by metroplex; 1 Week Ago at 08:45 AM.

  19. #19
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    755
    Not sure which parameter has a priority and comes into equation first but there are 3: ISS, OSS and Gear ratio.

  20. #20
    Advanced Tuner metroplex's Avatar
    Join Date
    Apr 2013
    Location
    Detroit, MI
    Posts
    772
    So, OSS= (Turbine Speed * ISS ) / Gear Ratio?