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Thread: Why does no one care about WOT TCC Lockup?

  1. #21
    I made a few more runs last night. I didn’t have the tcc learn turned off and thought it might be the cause of my inconsistency’s. It is still very inconsistent. One time it applies pressure mid 3rd. Next time in 2nd then off for 3rd then back on for 4th. Another time it applies pressure on 2nd and keeps it applied. Even when applied at what appears to be the max pressure of 113psi it slips 200-300rpm at wot.

    I hot wired it last night and it seems to work. No codes, no limp mode and full lock up. I have a pic but this site won’t let me upload a pic from my phone.

    The diagram shows 2 tcc noids with a green white to one and a yellow brown to the other. I found those wires in the passenger wheel well. I put a volt meter on them and looked for a change when applying the tcc with bidirectional control. The green/white didn’t seem to change. The yellow/brown went from 13volts down to 5.5volts indicating the noid has 7.5volts across it. I wanted to simulate this so I used an old school sliding resistor and shorted that yellow brown to ground through the resistor and adjusted the resistance until I saw the same 5.5volts. It ended up at 4ohms.

    After confirming that this was working in the garage I hooked up a control circuit and went for a spin. By grounding that yellow/brown(through a 4ohm resistor) I can get full lock up and am not setting any codes. The shifts are crisp but not the least bit harsh. I will be making some back to back runs at the track to see if it makes it any quicker or faster.
    2017 camaro ss a8 with low mount twins

  2. #22
    I have a pwm output available on my controller. It can go from 10-250hz. I am curious if I can get rid of the resistor and hook it up directly to the output with a duty cycle. 250hz seems kinda low. I might scope the factory output and see if it is pwm and if so at what frequency.
    2017 camaro ss a8 with low mount twins

  3. #23
    Advanced Tuner
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    Quote Originally Posted by parish8 View Post
    I have a pwm output available on my controller. It can go from 10-250hz. I am curious if I can get rid of the resistor and hook it up directly to the output with a duty cycle. 250hz seems kinda low. I might scope the factory output and see if it is pwm and if so at what frequency.
    I have to take back what I said about the ramp rate table not doing anything, it does seem to have a very small effect, but like you are thinking we must still be in some sort of adapt mode where it is trying to use slip as a feedback and its not straight up just locking. It is now seeming like its trying to lock at the end of second but it won't hit zero slip until about 5800 rpms.

    I am going to try tonight what happens when I lock it up with bi-directional controls if its not wet out.

    Does anyone know how much slip at WOT they are seeing with circle D's? Or any other aftermarket converters? Not sure who else does stuff for the 8L90?

  4. #24
    With the scan tool showing 113psi of tcc pressure I was seeing 200-300rpm Of slip with about 600hp. I have a circle d multi disk.

    With the bidirectional control I see 0 slip(+or- 20rpm on the scan tool). Not sure If I ever made a full run.

    Now with my direct control it went to 0 slip with a small bump of slip at each shift and then started showing a steady increase in slip from about 115mph to 135mph in 5th topping out with about 80rpm up there. It is such a steady ramp from 20-80 I kinda wonder if it is just a sensor thing.
    2017 camaro ss a8 with low mount twins

  5. #25
    I did call circle d today and ask how much hp I can expect that clutch to hold. He told me 1200-1300hp.

    lock up.jpg
    Last edited by parish8; 07-21-2020 at 07:47 PM.
    2017 camaro ss a8 with low mount twins

  6. #26
    Quote Originally Posted by parish8 View Post
    I did call circle d today and ask how much hp I can expect that clutch to hold. He told me 1200-1300hp.

    lock up.jpg


    Ok im going to try the hotwire trick. Did you cut the yellow brown and run a switch between it and the resistor then to ground? Im assuming

  7. #27
    There is more than one yellow/brown in that bundle, you have to check the voltage on that wire and trigger the lock up and see if it changes. You have to get it up to speed to do that.

    I did not cut the yellow/brown. Just striped it back a little and connected to it. Then to a resistor and then to the switch and then to ground. The resistor I used is a large ceramic wound resistor. The load is something like 22 watts if you use a 4 ohm resistor.

    I have a couple of video clips I can send ya. Friend me on Facebook and I will message them to ya. Jim Neuenfeldt

    My next plan is to scope it and see what the factory is doing/ if they are just pwm it then I will remove the resistor and do the same.
    2017 camaro ss a8 with low mount twins

  8. #28
    Quote Originally Posted by parish8 View Post
    There is more than one yellow/brown in that bundle, you have to check the voltage on that wire and trigger the lock up and see if it changes. You have to get it up to speed to do that.

    I did not cut the yellow/brown. Just striped it back a little and connected to it. Then to a resistor and then to the switch and then to ground. The resistor I used is a large ceramic wound resistor. The load is something like 22 watts if you use a 4 ohm resistor.

    I have a couple of video clips I can send ya. Friend me on Facebook and I will message them to ya. Jim Neuenfeldt

    My next plan is to scope it and see what the factory is doing/ if they are just pwm it then I will remove the resistor and do the same.

    I added you. I will probably tap in close to the tcm end of the harness since i have a sierra i bet my wires run differently than a camaro. So you tapped the wire. Then unlocked the tc in all gears in the tune?

  9. #29
    I did not turn off the lock up in the tune but I probably should at least at wot where this device is kicking in.
    2017 camaro ss a8 with low mount twins

  10. #30
    Quote Originally Posted by parish8 View Post
    I did not turn off the lock up in the tune but I probably should at least at wot where this device is kicking in.
    Ok so in the first vid you sent that was you controlling the output to the resistor correct?

  11. #31
    Yes. I can use anything I want to trip that output, currently it is set at over 85% tps and over 45mph.
    2017 camaro ss a8 with low mount twins

  12. #32
    Quote Originally Posted by parish8 View Post
    Yes. I can use anything I want to trip that output, currently it is set at over 85% tps and over 45mph.

    What is that setup your running?

  13. #33
    I am running a ms3pro ultimate for a pile of extra features. Port fuel, ignition, speed based dome boost control, traction control, 2step, 3step, aux fuel pump control, intercooler pump control, dash gauges, af/fuel pressure safety’s and logging everything under the sun. Now tcc lock up.

    It is a real bargain if you ask me.
    2017 camaro ss a8 with low mount twins

  14. #34
    Quote Originally Posted by parish8 View Post
    I am running a ms3pro ultimate for a pile of extra features. Port fuel, ignition, speed based dome boost control, traction control, 2step, 3step, aux fuel pump control, intercooler pump control, dash gauges, af/fuel pressure safety?s and logging everything under the sun. Now tcc lock up.

    It is a real bargain if you ask me.

    Your running this in addition to the e92? Is there a breakout harness that makes this plug and play or did you tap into the factory harness? Thanks

  15. #35
    Quote Originally Posted by DENALI62 View Post
    Your running this in addition to the e92? Is there a breakout harness that makes this plug and play or did you tap into the factory harness? Thanks
    There is no break out harness. Wires needed to be tapped in each of the 3 connectors to the ecm. I tapped everything right near the ecm. I was able to double tap most things. Cam, crank, tps(from pedal), flex fuel, map, maf, power. Had to install a 2nd iat sensor and my own speed sensors but I feel like there should be a way for the squirt to read the abs sensors.
    2017 camaro ss a8 with low mount twins

  16. #36
    More about the tcc lock up. I hooked up a scope and with bidirectional control the scope shows 63% dc and 3000hz. I can only get to 250hz with my controller. I think the resistor approach is going to be more like factory for that noid than a 250hz pulse.
    2017 camaro ss a8 with low mount twins

  17. #37
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    It was mentioned before, but worth mentioning again...HP Tuners doesn't have everything defined in the software. They often have to sift through the hex the hard way to produce the calibratables they have now. But there's a ton of stuff executed behind the scenes for a number of reasons. Typically, arbitration for control of hardware goes passenger safety>hardware safety>EPA requirements>driver comfort>performance. Passenger safety doesn't come into play much with a torque converter, so it comes down to mostly hardware safety and EPA's say-so. Low transmission line pressure due to low engine RPM/transmission pump speed is a big player - locking up a converter under high torque that isn't meant for it (single disc and the like) without enough pressure on the clutch will roast it. On the other hand, having an excess amount of pressure in the trans at all times to handle low RPM torque is bad for fuel economy. Pressure means torque loss, so the less the better in that case. The happy medium is to slip the converter clutch a bit to reduce energy loss to heat. There are also other software features in other modules on the CAN that can request TCC slip under certain conditions. AFM is one of them...during situations where torque request is higher than engine torque capacity, AFM itself can request TCC slip to increase transmission input torque to meet driver demand.

    I don't think you'll have a problem driving the TCC solenoid directly. There should be enough resistance in the coil in addition to being bathed in transmission fluid to prevent it from heating up too much. I used to lock up my converter with a ground switch in the cab because the HPT didn't have the knobs available to disable high throttle unlock. Wouldn't be a bad idea to use a latched relay circuit though, in case you forget to unlock it with an on/off switch.

  18. #38
    Quote Originally Posted by parish8 View Post
    More about the tcc lock up. I hooked up a scope and with bidirectional control the scope shows 63% dc and 3000hz. I can only get to 250hz with my controller. I think the resistor approach is going to be more like factory for that noid than a 250hz pulse.

    I really appreciate all thia research you are doing im sure there are others that will benefit as well. I am thinking about building a box that will function simarly without the added complexity of running an entire standalone.

  19. #39
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    Quote Originally Posted by smokeshow View Post
    It was mentioned before, but worth mentioning again...HP Tuners doesn't have everything defined in the software. They often have to sift through the hex the hard way to produce the calibratables they have now. But there's a ton of stuff executed behind the scenes for a number of reasons. Typically, arbitration for control of hardware goes passenger safety>hardware safety>EPA requirements>driver comfort>performance. Passenger safety doesn't come into play much with a torque converter, so it comes down to mostly hardware safety and EPA's say-so. Low transmission line pressure due to low engine RPM/transmission pump speed is a big player - locking up a converter under high torque that isn't meant for it (single disc and the like) without enough pressure on the clutch will roast it. On the other hand, having an excess amount of pressure in the trans at all times to handle low RPM torque is bad for fuel economy. Pressure means torque loss, so the less the better in that case. The happy medium is to slip the converter clutch a bit to reduce energy loss to heat. There are also other software features in other modules on the CAN that can request TCC slip under certain conditions. AFM is one of them...during situations where torque request is higher than engine torque capacity, AFM itself can request TCC slip to increase transmission input torque to meet driver demand.

    I don't think you'll have a problem driving the TCC solenoid directly. There should be enough resistance in the coil in addition to being bathed in transmission fluid to prevent it from heating up too much. I used to lock up my converter with a ground switch in the cab because the HPT didn't have the knobs available to disable high throttle unlock. Wouldn't be a bad idea to use a latched relay circuit though, in case you forget to unlock it with an on/off switch.
    Thanks for the info, it has always baffled me how transmissions can instantly increase hydraulic pressure to respond to a fast ramp up in engine torque, especially say at low rpms (where the engine is making almost full torque at part throttle). It seems to me there would be slippage in the clutch packs when that happens but then again I guess all the volumes are filled when the clutch packs are properly applied and it should theoretically be able to "instantaneously" increase the pressure before the engine can increase torque given the delay of when the TB sees the increase air versus when it gets to the cylinder?

  20. #40
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    Quote Originally Posted by cmitchell17 View Post
    Thanks for the info, it has always baffled me how transmissions can instantly increase hydraulic pressure to respond to a fast ramp up in engine torque, especially say at low rpms (where the engine is making almost full torque at part throttle). It seems to me there would be slippage in the clutch packs when that happens but then again I guess all the volumes are filled when the clutch packs are properly applied and it should theoretically be able to "instantaneously" increase the pressure before the engine can increase torque given the delay of when the TB sees the increase air versus when it gets to the cylinder?
    Nothing happens instantaneously. But yes, when you have a dead head style clutch pack/clutch drum where the inlet also serves as the primary fluid outlet, pressure rise can be very rapid. However it may not be rapid enough in many cases so the big manufacturers all have tons of adaptive control strategies in their arsenal to improve all aspects of the powertrain. These strategies are anything from feedback/reactive learning controls to purely predictive control. For example, the predictive airflow model GM uses alongside dynamic airflow; throttle position, throttle opening rate, MAP, a modeled or measured upstream pressure and a manifold volume are all used to generate a cylinder airmass prediction and inject fuel based on that prediction before the actual measurement of airflow even takes place. If there is an actuator or physical aspect of the system that you can anticipate will have an effect elsewhere, even if only slightly, you can bet there is software that attempts to get ahead of the game and be ready to accommodate transient or nonlinear behavior. Modern transmissions are no different - if you stab the throttle quickly in a new vehicle with an automatic, most manufacturers have incorporated software features that will anticipate aggressive driving and change how the transmission shifts. I used to design that software for hybrid powertrain, really cool stuff - it's pretty wild the depth that the OEs go to in order to build even plain jane vehicles.