Page 1 of 2 12 LastLast
Results 1 to 15 of 19

Thread: 4L60E tuning in $0D

  1. #1
    Fuel Injected! Roadknee's Avatar
    Join Date
    Dec 2013
    Location
    North Central Washington
    Age
    54
    Posts
    245

    4L60E tuning in $0D

    I'm seeking insight into how the following tables under 4L60E line pressure parameters affect transmission operation in $0D:

    Pressure ramp delay time vs tps vs shift (sec)
    Extended ramping pressure time vs tps vs shift (sec)
    Initial ramping pressure vs tps vs shift (psi/sec)
    Ramping pressure vs tps vs shift (psi/sec)
    Post shift ramp time vs tps vs shift (sec)

    In the stock bin for my 1995 K1500, these tables are mostly unpopulated. There are some negative values (psi/sec) in the ramping pressure vs tps vs shift for the 1-2 shift. There is also a 0.5 second value in the corresponding cells in the pressure ramp delay time vs tps vs shift.

    I assume these tables modify line pressure during the line pressure modulation time during an upshift, but don't understand exactly how they function. I'd appreciate any guidance.

  2. #2
    Fuel Injected! Roadknee's Avatar
    Join Date
    Dec 2013
    Location
    North Central Washington
    Age
    54
    Posts
    245
    I looked through several of the $0D bins. In general the V8 bins are similar and the 4.3 V6 bins are similar to one another. Unfortunately there was not a performance application that used $0D for me to try and learn from. I spent a little bit of time experimenting with the above tables, but not enough to draw any conclusions. More on that later.

    I've made several changes to upshift/downshift mph vs tps vs gear tables and the TCC lock and unlock tables. I have it rev a little higher before upshift, downshift sooner, engage TCC later and disengage TCC sooner for a more performance oriented feel. Much of this is personal preference.

    The biggest improvement was locking the TCC in third gear. With the stock BJYL tune, the trans upshifts to 4th at 29 mph under light throttle and never locks the TCC in third. The TC slips considerably when running around town at 35 mph in fourth gear. I delayed upshift to 4th under light throttle to 44 mph and engage TCC in third at 32 mph. It feels a lot better now and takes considerably less throttle running around town.

    I also set the Lower Low Speed TPS and Upper Low Speed TPS to Prevent TCC Cycling to 0% to keep the TCC locked on deceleration at 0% TPS. As long as MPH is below the MPH for Using Low Speed TPS Thresholds the TCC will remain locked. I temporarily set the Low MPH to 84 and high MPH to 86 for a test. The TCC would remain locked on deceleration in fourth gear, and it behaves like a manual trans. In third gear, the TCC appears to remain locked, but the trans shifts to 4th at 0% TPS. It loses a little rpm on deceleration. As soon as I touch the throttle it returns to 3rd gear TCC locked rpm. If I pull the shift lever into third gear, it stays in third and the TCC stays locked on deceleration, and it behaves like a manual trans. I searched through the BIN, but couldn't find any way to keep the trans in 3rd gear during deceleration with the selector in fourth gear.

    There are a second set of parameters, High Speed TPS to Prevent Repeated TCC Cycling. As long as these are populated with positive numbers, the TCC will disengage on deceleration when the actual vehicle speed is above the Upper and Lower MPH for Using Low Speed TPS thresholds. I set these to 46 and 44 mph, respectively. Thus, in 4th gear and above 46 mph, the TCC unlocks on deceleration. I didn't care for the feel with it locked in fourth during DFCO. It really slows the truck down.
    Last edited by Roadknee; 03-22-2014 at 03:38 AM.

  3. #3
    billygraves
    Guest
    ..............
    Last edited by billygraves; 06-30-2019 at 06:19 PM.

  4. #4
    Fuel Injected! Roadknee's Avatar
    Join Date
    Dec 2013
    Location
    North Central Washington
    Age
    54
    Posts
    245
    I zero'd the negative numbers in the 1-2 ramping pressure tables. It was inconclusive whether it made any difference. So I turned to the 0-64 mph and 64-128 mph pressure tables. I compared these to the 1994 Cadillac V4P which is said to shift pretty well. My K1500 pressures were higher below 50% TPS and the V4P tables were higher 50% and above. I copied the V4P values 50% TPS and above into my K1500 tables. The top several rows in the V4P tables go to 90 psi where my K1500 pressures peak at 59 psi.

    What a difference. The WOT 1-2 shift is firm. It doesn't bang; just a nice firm shift. The 2-3 shift actually hit a little too hard, so I reduced the pressures either side of 60 mph in the proximity of the WOT 2-3 shift to 78 psi. This made the 2-3 shift feel like the 1-2 shift. When datalogging, the WOT shift times are about 0.3 seconds, compared to 0.5 seconds with the stock K1500 tables. Downshifts feel a lot better too. Nothing hits hard; just feels like a daily driven performance trans should.

    Earlier I modified the appropriate table to lock the TCC in third gear. One thing I did not like was the way it unlocked prior to the 3-4 shift. Prior to the shift it would unlock and the motor would rev up for several seconds, then shift with an rpm drop. Not a big deal; just kinda annoying. I unchecked a flag to unlock TSS during upshift. I was a bit nervous about this thinking the shift would bang with the TCC locked, but its fine. The 3-4 shift now feels similar to how the TCC locks in OD. One interesting observation about the code is that in order for the TCC to remain locked during upshift, the 4th gear TCC release speed must be less than the 3-4 upshift speed. If the 4th gear TCC release speed is higher than the 3-4 shift speed, the TCC will unlock prior to upshift.

    I haven't had a chance to feel a 3-4 upshift with the TCC locked at higher speed (say 75 mph) and higher TPS. I'll have to see if it hits too hard. I did program the shift points to prevent 3-4 shifts above 50% TPS so I think it will be fine since the shift pressures are relatively low. Will report back if its an issue.

  5. #5
    billygraves
    Guest
    ..............
    Last edited by billygraves; 06-30-2019 at 06:19 PM.

  6. #6
    Fuel Injected! Roadknee's Avatar
    Join Date
    Dec 2013
    Location
    North Central Washington
    Age
    54
    Posts
    245
    Quote Originally Posted by billygraves View Post
    All I can tell you is Good Luck and if you cook a set of clutches, I hope you don't mind pulling it out to overhaul it. It usually gets expensive. If I had an L60 all I would change is the steady state pressure to increase it, increase the upshift pressures and really add some PTS to the TCC ON in 4th.
    If you think the 10 pack of the 3-4 clutch is a good set up, you are mistaken. The clutch design was NOT THOUGHLY thought out. This is why GM ran test after test on all of these and did NOT change to them. They seem like a good idea but do not hold up with any HEAT. The clutches are very thin and will NOT tolerate HEAT and there is not enough capacity in the steels to carry the heat from the shift to the oil without going over the temp of the clutch material or bonding agents. I would use the OEM 7 cl 3-4 set up thickness. Never tow or run a L60 in 4th with TCC on at low Engine RPM. It will burn the 3-4 cl. Best of luck to ya.
    Thanks for the feedback Billy. I post (1) to share my observations with others and (2) obtain feedback if something in my tuning methodology may cause issues. I won't even pretend to have a thorough understanding of the mechanics of the 4L60E. Thus, for the benefit of myself and others that may read this, could you please describe what specifically in my tune puts the 3-4 clutches at risk? Also, does my OEM 1995 trans have the 10-clutch 3-4 pack? Thanks.

  7. #7
    billygraves
    Guest
    .........
    Last edited by billygraves; 06-30-2019 at 06:19 PM.

  8. #8
    Fuel Injected! Roadknee's Avatar
    Join Date
    Dec 2013
    Location
    North Central Washington
    Age
    54
    Posts
    245
    I set up a monitor to datalog TPS, trans temp, torque signal pressure and RPM and experimented with the following tables:

    Pressure ramp delay time vs tps vs shift (sec)
    Extended ramping pressure time vs tps vs shift (sec)
    Initial ramping pressure vs tps vs shift (psi/sec)
    Ramping pressure vs tps vs shift (psi/sec)
    Post shift ramp time vs tps vs shift (sec)

    Preliminary findings are summarized below. These are preliminary because I failed to save the datalog, and am going off memory what I observed. Note my son was driving the truck while I worked the laptop.

    1) Ramping pressure (psi/sec) increases or decreases line pressure for the actual time (sec) taken to complete the shift.

    2) Pressure ramp delay time (sec) delays the initiation of ramping pressure. For example, if delay time is set for 0.5 second, the shift will begin, and continue for 0.5 second until the onset of any ramping pressure change.

    3) Initial ramping pressure (psi/sec) works in conjunction with the pressure ramp delay time. Some stock 4.3V6 tunes have 0.3 second delay time, positive initial ramping pressure and negative ramping pressure. Line pressure is increased at the initial ramping pressure rate for 0.3 seconds, and then reduced at the ramping pressure rate for the duration of the shift. (Note: It appeared in the data monitor that the initial ramping pressure took effect before any engine RPM reduction from the shift. However, I lost the datalog and will need to retest and verify this later.)

    4) Extended ramping pressure time (sec) continues to increase or decrease pressure after the shift is completed at the ramping pressure rate. Pressure cannot exceed 90 psi (maximum in the BJYL tune) or fall below 0 psi.

    5) Post shift ramp time (sec) was inconclusive. I'll need to do more testing. I assume this is the amount of time to return line pressure to "normal" after the shift is completed.

    It also appears that the total time for shift pressure ramping can not exceed the line pressure modulation time in the 4L60E Line Pressure Parameters (1.2 seconds for all upshifts in the BJYL tune).

    And the good news is trans temps stayed cool and I don't appear to have burnt any clutches.
    Last edited by Roadknee; 03-24-2014 at 04:38 PM.

  9. #9
    billygraves
    Guest
    ..............
    Last edited by billygraves; 06-30-2019 at 06:19 PM.

  10. #10
    RIP EagleMark's Avatar
    Join Date
    Feb 2011
    Location
    North Idaho
    Age
    63
    Posts
    10,477
    Quote Originally Posted by billygraves View Post
    If you start to decrease pressure in a L60 and it feels better or softer, then more than likely you are slipping some of them during the shift. Keep in mind that the L60 calibrated pressures on the low side to help with fuel economy where L80 error on the durability side and added 40 to 50% additional.
    Given a stock 4L60E calibration... what pressure or pressures would you adjust? For overall durability. Not for economy or for gentle shifts which GM called sales shifts, you know the big 1,2,3 sssslllluuuusssshhhh feel of a Caddilac. I like to feel a trans shift. But I do not like to feel it bang. I'm not asking for shift feel, I'm asking for overall safe improvements!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  11. #11
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    Euless, TX
    Posts
    2,305
    Quote Originally Posted by EagleMark View Post
    Given a stock 4L60E calibration... what pressure or pressures would you adjust? For overall durability. Not for economy or for gentle shifts which GM called sales shifts, you know the big 1,2,3 sssslllluuuusssshhhh feel of a Caddilac. I like to feel a trans shift. But I do not like to feel it bang. I'm not asking for shift feel, I'm asking for overall safe improvements!
    On the otherhand I like how my 4L80E shifts with authority. Tends to break the tires loose anywhere over 1/2 throttle on the 1-2 shift.

  12. #12
    Fuel Injected!
    Join Date
    Aug 2014
    Age
    74
    Posts
    62
    Quote Originally Posted by EagleMark View Post
    Given a stock 4L60E calibration... what pressure or pressures would you adjust? For overall durability. Not for economy or for gentle shifts which GM called sales shifts, you know the big 1,2,3 sssslllluuuusssshhhh feel of a Caddilac. I like to feel a trans shift. But I do not like to feel it bang. I'm not asking for shift feel, I'm asking for overall safe improvements!
    Was there ever a reply to this question? I, too, would like some advice on safe pressures for safe, firm shifts.

  13. #13
    billygraves
    Guest
    ................
    Last edited by billygraves; 06-30-2019 at 06:20 PM.

  14. #14
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    1,022
    Taking a quick look it appears the tables saying psi are wrong in this xdf like it is in other definitions. The 4L60e operates at 200psi plus so how can 90psi make sense for a maximum line pressure? With the max pressure scalar left set at 90psi, the code will take the main pressure table and then add any modifier table values before looking the answer up in the force motor table and applying that current to the line pressure. The "psi" adding the tables together is basically divided by the max pressure scalar so increasing the max pressure and increasing the tables would actually do nothing useful.
    Last edited by lionelhutz; 08-28-2014 at 09:59 PM.

  15. #15
    billygraves
    Guest
    .........
    Last edited by billygraves; 06-30-2019 at 06:20 PM.

Similar Threads

  1. Replies: 22
    Last Post: 10-25-2021, 05:19 AM
  2. 4L60E is out and 4L80E about to go in.
    By Fast355 in forum OBDII Tuning
    Replies: 40
    Last Post: 09-27-2013, 12:10 AM
  3. 4L60E making noise
    By chris in forum Gear Heads
    Replies: 2
    Last Post: 09-13-2013, 02:47 AM
  4. 350 TPI with a 4L60E, What ECM will control both?
    By HotRodV6 in forum GM EFI Systems
    Replies: 4
    Last Post: 09-08-2013, 10:00 PM
  5. VSS from Speedo to ECM or DRAC/VSSB 4L60E
    By Nasty-Z in forum GM EFI Systems
    Replies: 23
    Last Post: 02-15-2012, 07:33 AM

Bookmarks

Posting Permissions

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