4L80E Tuning Assistance

[Devon24/7]

I have a 06 avalanche I've done a 80E swap to, and I'd like y'all to look over my tune file and see where I could improve. At the moment shift pressures feel like they're fine, shift desired time I'm still tweaking. I'm trying to see if they're is anything I can do to improve the performance of the stall I installed/improve downshift response. I have a circle d 3200-3400 stall triple disc, red clutches, HD2 shift kit, and the motor is stock other than a intake and a cat-back exhaust. Anyone have a triple disc Circle D converter? if so what's y'alls min/max duty cycle? I'm trying to learn and little nervous changing things lol, but I bet we all start there.

Also does HP Tuners allow you to lock the converter in 1st WOT?

[TransGo Robert]

I have a 06 avalanche I've done a 80E swap to, and I'd like y'all to look over my tune file and see where I could improve. At the moment shift pressures feel like they're fine, shift desired time I'm still tweaking. I'm trying to see if they're is anything I can do to improve the performance of the stall I installed/improve downshift response. I have a circle d 3200-3400 stall triple disc, red clutches, HD2 shift kit, and the motor is stock other than a intake and a cat-back exhaust. Anyone have a triple disc Circle D converter? if so what's y'alls min/max duty cycle? I'm trying to learn and little nervous changing things lol, but I bet we all start there.

Also does HP Tuners allow you to lock the converter in 1st WOT?

There is no oil going to the TCC solenoid in first gear so there is no way to get lock-up in first no matter what you do with the computer command.

[04silverado6.0]

Shift scheduling-d1 urban- 1-2 shift i would set to 255 across the row. Shift times look fine, you might lower the 3-4 time to around .200-.150. Make sure you arent slipping the verter clutches depending on the material. I would disable converter shift lock personally as well.

[blindsquirrel]

There is no oil going to the TCC solenoid in first gear so there is no way to get lock-up in first no matter what you do with the computer command.

And if you could do it, all you'd be doing is killing all the torque multiplication from the converter. I don't understand why people repeatedly keep thinking this is something you'd want.

[Devon24/7]

I agree it's just what I've read. The only way to see if they're is really any difference is on a dyno. I just was lead to believe at X point there is a loss in multiplication that locking up could fix, and 1:1 rpm which would allow for more MPH?

[Devon24/7]

I'll try doing that thanks. What makes you think I should turn off the shift lock? Just wondering? I'm Assuming because of what blindsquirrel replied? Also what is the lowest shift time you can command safely on a 80E? I believe shift pressures play into this as well.

[kingtal0n]

Shift time is for adaptives of a stock unit. Once you modified the 4l80e and use a higher stall converter the shift times may not be reported properly in the ECU and this could lead to over-adaption (crazy pressure adjustments automatically).

Generally disable adaption and ignore shift time for modified units.

The right way to adjust shift pressure is using a pressure gauge on the unit. 180PSI is considered good WOT pressure for perhaps 800rwhp or less (its not the power output of the engine that matters when it comes to trans pressure but this is how many people prefer to relate the pressure to output situations). Some will use 200psi. It depends on many factors including how the unit has been modified (OEM boost valve or?) and what type of leverage (gearing) and tire types are used. More sticky tires, less leverage, more torque output, more pressure needed to prevent general slip, not just shift slip.

If the unit has lube to line modification it will influence baseline pressure / duty (mA of current to EPC solenoid needs to be reduced across the board to maintain even stock pressure)
Shiftlock will increase wear and tear overall of the unit and is generally not desirable.
Torque management can drastically improve the lifespan of the unit and should be used as much as possible IMO
Most common mod is duel fed direct drum (did you also remove the seal in the direct drum? I do not remove this seal) but many also prefer to add a bleed hole under direct piston which will also require a bump in baseline pressure like the lube to line modification

I do not recommend locking the converter at WOT no matter what type of converter. Yes if the unit is triple disc it can hold a WOT and make some little extra MPH but the trade off is reduced life span. Its fine if you are racing or making a king dyno pass once or twice. But I would not do it for normal operation daily driver stuff.

[ns158sl]

Duty Cycle min should be around 90. Those clutches are not meant to slip. Its going to be firm, but thats what a triple disc supposed to do. To soften the feel, you can push the lockup MPH later so it doesnt feel like such a shift, granted with a medium stall like that, there is nothing you can do about it. Shift lock is not going to do you any favors. Power to weight ratio is the key player there. Try 1000hp and 4500lbs and shift lock was still slower in the quarter mile. There is a ton of info on tuning a 4l80 on this forum. A lot might not be in the trans forum.

[kingtal0n]

I've always wondered what sonnax is talking about here with this
notes_on_pwm.jpg


From what I can tell the converter pressure is a release thing, not an apply thing. I asked YANK and Dave said it would take a lot of pressure to damage a converter (clutch?) and that he doesn't think hes ever seen it in the 4l80e.

So what do they mean "aftermarket programming" 100% duty cycle cause converter pressure to exceed intended values? Isn't there a converter limit valve which limits the max pressure anyways?

But... Sonnax. I don't get it. And that warning about thrust worries me.

[ns158sl]

My guess is something hardcoded in the ECM. 100 percent must give it full line pressure? never checked. Main thing is leave max 99 or 98 and min around 90ish

[TransGo Robert]

I've always wondered what sonnax is talking about here with this
notes_on_pwm.jpg


From what I can tell the converter pressure is a release thing, not an apply thing. I asked YANK and Dave said it would take a lot of pressure to damage a converter (clutch?) and that he doesn't think hes ever seen it in the 4l80e.

So what do they mean "aftermarket programming" 100% duty cycle cause converter pressure to exceed intended values? Isn't there a converter limit valve which limits the max pressure anyways?

But... Sonnax. I don't get it. And that warning about thrust worries me.

When the lock-up is commanded OFF in a two path converter, converter charge is the pressure and flow keeping the clutch off against the apply pressure. Once lock-up is commanded ON the flow reverse and now your converter charge pressure is what applies the clutch. You must limit this pressure or else the lock-up apply piston will bow and end up looking like a bowl of soup since there is nothing in the center in the back to prevent it from moving.

[kingtal0n]

When the lock-up is commanded OFF in a two path converter, converter charge is the pressure and flow keeping the clutch off against the apply pressure. Once lock-up is commanded ON the flow reverse and now your converter charge pressure is what applies the clutch. You must limit this pressure or else the lock-up apply piston will bow and end up looking like a bowl of soup since there is nothing in the center in the back to prevent it from moving.

Okay, but how do we tell or measure how much pressure vs duty cycle of the PWM TCC solenoid? It isn't line pressure like from the side of the transmission. Its limited by the TCC limit valve, so is it even possible to provide too much pressure and if so how can anybody tell, you put 90% duty cycle or 95% or 98% or what is the magic number ? Most people use 100% and that is what this sonnax is warning about

[TransGo Robert]

Okay, but how do we tell or measure how much pressure vs duty cycle of the PWM TCC solenoid? It isn't line pressure like from the side of the transmission. Its limited by the TCC limit valve, so is it even possible to provide too much pressure and if so how can anybody tell, you put 90% duty cycle or 95% or 98% or what is the magic number ? Most people use 100% and that is what this sonnax is warning about

There is no such thing as a TCC limit valve in a 4L80E, all you have is a TC Limit valve that limits the pressure going to the converter when the lock-up is commanded OFF. Once the lock-up is commanded ON that valve then limits cooler pressure and has no connection with the converter pressures at all. What controls the apply pressure is the on time duty cycle % of the
TCC solenoid, the TCC regulator valve spring force and line pressure which feeds the solenoid. However the solenoid is not able to output the same as line when it is really high. You cannot measure that pressure without going to the trouble of plumbing the valve body for a gauge or transducer. Best thing is to just keep it stock sincere is no need to raise it above factory pressure (usually about 120 psi max for factory stamp steel piston) since it applies only where there is very little load. Raising the apply pressure will just damage thing without possibly giving you any benefits. However you could raise the ramp up time to shorten the time is slips during the apply. Or you could install our valve and for the optional one-off modification binding you direct apply with regulation protection against over pressure. https://transgo.com/product-details/4l80-tcc-regulator/

[kingtal0n]

There is no such thing as a TCC limit valve in a 4L80E, all you have is a TC Limit valve that limits the pressure going to the converter when the lock-up is commanded OFF. Once the lock-up is commanded ON that valve then limits cooler pressure and has no connection with the converter pressures at all. What controls the apply pressure is the on time duty cycle % of the
TCC solenoid, the TCC regulator valve spring force and line pressure which feeds the solenoid. However the solenoid is not able to output the same as line when it is really high. You cannot measure that pressure without going to the trouble of plumbing the valve body for a gauge or transducer. Best thing is to just keep it stock sincere is no need to raise it above factory pressure (usually about 120 psi max for factory stamp steel piston) since it applies only where there is very little load. Raising the apply pressure will just damage thing without possibly giving you any benefits. However you could raise the ramp up time to shorten the time is slips during the apply. Or you could install our valve and for the optional one-off modification binding you direct apply with regulation protection against over pressure. https://transgo.com/product-details/4l80-tcc-regulator/

For people like me who have a triple clutch lockup converter, ex. I use Yank 3200 SS triple clutch, I though we need the pressure to apply at wide open throttle if necessary. I don't personally apply at WOT but I think many do.

So I wonder how can we 'not use 100% TCC duty cycle' while also 'using the most pressure possible to lock the triple clutch discs' and how this interplays with the issue of crank thrust and pump wear.

Is the "On/Off" modification suitable for triple clutch lockup converters? How does the 'on / off ' regulate pressure whereas turning the solenoid "on" directly (PWM 100% using a switch) cannot, some exhaust fluid and a spring perhaps?

[TransGo Robert]

For people like me who have a triple clutch lockup converter, ex. I use Yank 3200 SS triple clutch, I though we need the pressure to apply at wide open throttle if necessary. I don't personally apply at WOT but I think many do.

So I wonder how can we 'not use 100% TCC duty cycle' while also 'using the most pressure possible to lock the triple clutch discs' and how this interplays with the issue of crank thrust and pump wear.

Is the "On/Off" modification suitable for triple clutch lockup converters? How does the 'on / off ' regulate pressure whereas turning the solenoid "on" directly (PWM 100% using a switch) cannot, some exhaust fluid and a spring perhaps?

The thrust bearing issue of the engine is a red Herring, you can ignore that nonsense. As for the aftermarket converter with tipple clutch they normally used billet piston so they can handle the pressure no problem unlike the OE piston designed to flex to work hand in hand with its tapper. I would be very surprised if there was an issue on those ramping it up to 100%. As for how our kit does it we modify the separator plate and then to take the PWM part out of the equation and use a spring to regulate the apply. It would be a bit too complex to try to explain how we do it here.

[kingtal0n]

Very interesting. Thank you, you have answered some questions that I have had for quite a while and I feel confident I did the right thing in my tune file using 99% duty cycle PWM for the triple disc. It never slipped and I was only worried about crankshaft thrust. I put about 50k miles on it so far and I used a test engine- a free LM7 to see how long it would last. No problems to speak of yet. I am getting anxious to drop in the L33 I have sitting here. I bet this test engine goes 100k @ 600rwhp (300k total miles) and comes apart with a mint set of bearings and hopefully good looking thrust washers and I will proceed.

[TransGo Robert]

Very interesting. Thank you, you have answered some questions that I have had for quite a while and I feel confident I did the right thing in my tune file using 99% duty cycle PWM for the triple disc. It never slipped and I was only worried about crankshaft thrust. I put about 50k miles on it so far and I used a test engine- a free LM7 to see how long it would last. No problems to speak of yet. I am getting anxious to drop in the L33 I have sitting here. I bet this test engine goes 100k @ 600rwhp (300k total miles) and comes apart with a mint set of bearings and hopefully good looking thrust washers and I will proceed.

Always remember when it comes to crankshaft thrust that in order to push on something you also have to push against something on the opposite direction side. So the same force applied to the crank will be applied to the pump. The pump just cast iron and can't take much force, it will get destroyed wayyyyyy before the crankshaft thrust bearings could ever get hurt. Here's a good video covering this subject quite well by Dennis Madden at ATRA https://youtu.be/3Uy65ttomn8?si=eD5mC1RfZmZmJuQM which is for the most part correct. That should put your mind at ease about this common crankshaft thrust scare.

[kingtal0n]

Always remember when it comes to crankshaft thrust that in order to push on something you also have to push against something on the opposite direction side. So the same force applied to the crank will be applied to the pump. The pump just cast iron and can't take much force, it will get destroyed wayyyyyy before the crankshaft thrust bearings could ever get hurt. Here's a good video covering this subject quite well by Dennis Madden at ATRA https://youtu.be/3Uy65ttomn8?si=eD5mC1RfZmZmJuQM which is for the most part correct. That should put your mind at ease about this common crankshaft thrust scare.

I review the video and I thought about it. It is helpful but I think there are overlooked issues that I cannot easily determine. I am not a converter designer or front pump designer I have only the textbook references and I don't want to get too deep into published documents for this simple issue. I just wish to review the situation and pick out some details.

First, in the video there is pressure/area calculation typical for hydraulic on center hub. However the bolt area of the flex plate is neglected and the distance from the center hub to bolt area which is a moment and potentially inertial issue at first glance, imagine pressing into all of the bolt area on the flex plate there is a force times length applied to the hub in same axis. I think that will be pressure over area for the hub plus bolt area, plus force times length for the bolt to center moment plus inertial force. By inertia I mean the mass of the portion of the engine, crankshaft and flexplate as it is pulled or pushed over some time, not the moment of inertia of the drivetrain or engine components being accelerated/decel.

Next, the fluid forces seem obscure as the pressure of the converter inlet does not seem to be equal or relevant with respect to the fluid pressure supplied by a pump. For example the pump may supply 205PSI of line pressure but the converter only has 80psi of that. I cannot calculate the pressure applied to the pump- equal and opposite, sure, but what is the hydraulic apply area internal to the pump where pressure originates and how is that referenced with the total line pressure supplied by the pump? In other words, the converter has a physical attachment to the engine in the X-axis (inline with bolt direction on the flex plate) but it has
1. apparent orifice regulation and
2. no physical attachment in the x-axis to the pump, There is a space between the converter and pump called converter pull out.
Therefore the only way to apply force to the pump in the x-axis must be via fluid pressure, and fluids apply over some area, therefore it could be a very small area as with any other hydraulic system a small area, small force on the pump side could result with a large force over large area on the flex plate side, like a jack raising a car for example. That tells me the pump could exert tremendous force on the crankshaft while experiencing very little force itself.

Finally the cooler flow influence on converter pressure really makes me wonder about a great deal of potential issues there due to the aforementioned friction component. If the converter flow is regulated by pressure then adding longer lines, more friction, will decrease final pressure and total flow, it can't raise the converter pressure, only starve the lube circuit gradually, just like pressure regulated oil pump. However the 4l80e may not be regulated during lockup condition, I believe it was mentioned the limit valve only functions during unlocked. Nevertheless 100% PWM or DC signal is 'all its got', but I believe that only stands for a portion of total line pressure. In other words 100% PWM TCC for 80PSI vs 150PSI of line pressure is two completely different converter pressures despite both having 100% PWM TCC signal. The regulating feature appears to be the line pressure during lockup as opposed to a limiter valve unlocked. If this is correct then the main issue appears to be regulating PWM for WOT condition to some sane value of converter:line pressure ratio, not part throttle or cruise when the line pressure is low, which appears to be dependent on the cooler flow (while locked) because of lack of regulating valve. My troubling thought is that, while monitoring transmission fluid temperature while locked, cruising, if the temperture remains very low could it be that the converter flow rate is too low, and the converter is over heating while the fluid in the trans is staying cold? The cooler flow being so slow that it has plenty of cooling ability before returning to the pan while fluid leaving extremely hot and slowly from the converter? That is my troubling conditional thinking.

[TransGo Robert]

First, in the video there is pressure/area calculation typical for hydraulic on center hub. However the bolt area of the flex plate is neglected and the distance from the center hub to bolt area which is a moment and potentially inertial issue at first glance, imagine pressing into all of the bolt area on the flex plate there is a force times length applied to the hub in same axis.

You are thinking of this as if it was torque using a rotating lever. There is no leverage here as there is no pivot point or fulcrum, the thrust force applied in the center is the same as what is applied further out.

Next, the fluid forces seem obscure as the pressure of the converter inlet does not seem to be equal or relevant with respect to the fluid pressure supplied by a pump. For example the pump may supply 205PSI of line pressure but the converter only has 80psi of that.

Yes, two completely different pressures. Line is what the pressure regulator valve sends to the clutches and brakes in the transmission, while the converter charge pressure is what is sent to the converter. It is much lower than line and limited by the actuator feed limit pressure.

no physical attachment in the x-axis to the pump, [/B] There is a space between the converter and pump called converter pull out.
Therefore the only way to apply force to the pump in the x-axis must be via fluid pressure, and fluids apply over some area, therefore it could be a very small area as with any other hydraulic system a small area, small force on the pump side could result with a large force over large area on the flex plate side, like a jack raising a car for example. That tells me the pump could exert tremendous force on the crankshaft while experiencing very little force itself.

Now you are thinking of different ratio of apply area of the hydraulic force like in a press or an hydraulic jack. The hydraulic pressure here is applied over the exact same area towards the pump as it is towards the crankshaft. The area of the converter bigger than he hub is under the same pressure but confined where it pushes against the interior walls of the converter trying to make the converter itself grow bigger, but it does not generate any thrust force against the transmission or the engine.

I believe that only stands for a portion of total line pressure. In other words 100% PWM TCC for 80PSI vs 150PSI of line pressure is two completely different converter pressures despite both having 100% PWM TCC signal.

The TCC solenoid is fed full line pressure, however it cannot flow enough due to its port sizes even at 100% duty cycle to output more than 120 psi. The OE spring on the TCC regulator valve cancels the first 33 psi from that, so the max pressure the TCC regulator valve can send to the converter when in lock-up is limited to roughly 87 psi from factory.

…which appears to be dependent on the cooler flow (while locked) because of lack of regulating valve.

Cooler flow is not affecting converter pressure once in lock-up, that’s now two separate circuits.

[kingtal0n]

You are thinking of this as if it was torque using a rotating lever. There is no leverage here as there is no pivot point or fulcrum, the thrust force applied in the center is the same as what is applied further out.

Yes, two completely different pressures. Line is what the pressure regulator valve sends to the clutches and brakes in the transmission, while the converter charge pressure is what is sent to the converter. It is much lower than line and limited by the actuator feed limit pressure.

Now you are thinking of different ratio of apply area of the hydraulic force like in a press or an hydraulic jack. The hydraulic pressure here is applied over the exact same area towards the pump as it is towards the crankshaft. The area of the converter bigger than he hub is under the same pressure but confined where it pushes against the interior walls of the converter trying to make the converter itself grow bigger, but it does not generate any thrust force against the transmission or the engine.

The TCC solenoid is fed full line pressure, however it cannot flow enough due to its port sizes even at 100% duty cycle to output more than 120 psi. The OE spring on the TCC regulator valve cancels the first 33 psi from that, so the max pressure the TCC regulator valve can send to the converter when in lock-up is limited to roughly 87 psi from factory.

Cooler flow is not affecting converter pressure once in lock-up, that’s now two separate circuits.

Well I feel a little better at least. I should spend more time reviewing the fluid pathways, I completely forgot about the AFL. I am still not sure about the flex-plate bolt area though. The hub of the converter kind of slips into the flex plate- the holes match size. That doesn't really seem like a major pressure apply area to me. Instead the bolt area where the converter bolts to the flexplate is the stationary connectivity at my first glance. And the distance from the bolt area to the hub is the bending or torque apply force, e.g. when the bolts are farther away from the center of the flex plate, there is more bending or torque applied at the center.

Actually I found what I Was looking for I think this is what I am imagining
atesteo-blog-flexplate-concept-vehicle-equipment-design1-960x540-1.jpg
https://www.atesteo.com/en/flexplate/

Anyways. It sounds like I can apply full TCC PWM or *on/off* without too much concern. Which is my main concern. Thanks you have no idea how long I've worried about that thrust. I actually put a test engine in the car to see how long the thrust would last- so far 55,000 miles and 6 years no issues. Maybe its time to put the real engine in.