Predicted Engine Torque Source = Trans?

[GrannySShifting]

ECM 12820 is the table number.

Is there a way to search in Editor to find tables, say type that number in and table pops up

[johnny_boii]

Is there a way to search in Editor to find tables, say type that number in and table pops up

Edit > Navigator > Type in the number

[pathosflux]

Reviving this thread for a bit. I'm seeing the same problem with my 2017 Corvette grandsport A8. Whenever torque gets over a certain value the Predicted Engine Torque Source switches from axle to trans and starts to close the TPS. I have access to table #12820, which is all set to 8192. Is there a similar, but different table in the A8? I've looked through the ECM and don't see anything else that would be limiting me in this way. I can post logs if this helps, but figuring someone else might know the answer here.

[veee8]

Max torque per gear vs. RPM in the A8 TCM.

[pathosflux]

Ah... unfortunately the 2017 A8 TCM is locked. Does this mean I need to send my unit into HP tuners to get it unlocked? Can you show me a screenshot of this table?

[lt1z350]

Yes we “2017 up crowd” have to mail them the tcm pay to get it unlocked then pay for 4 credits to tune it. At around 700whp on my bolt on zl1 the only thing I have noticed is its slow to open from a dig or if I let the car down shift on its own. But if I manually down shift bring the rpm up like a roll race and nail it the tps will follow my foot. This is a guess on my hp but I was out of fuel on 93 alone and running quite a bit of meth just to run E35 so feel like 700 whp is being conservative considering the car can trap the 140 range in the summer Florida heat. By redoing my e85 virtual torque I have the trans shifting faster then ever with out touching the tcm. So unless I can get 100 percent tps from a dig I see no point in paying all that money right now. I would like it to automatically shift at a higher rpm but for now will use paddles to make the 6600-6700 rpm shifts I have been doing. I just slap it at 6500 and it takes a good 100-200 rpm to happen as pulling so hard.

[cmitchell17a]

Yes we ?2017 up crowd? have to mail them the tcm pay to get it unlocked then pay for 4 credits to tune it. At around 700whp on my bolt on zl1 the only thing I have noticed is its slow to open from a dig or if I let the car down shift on its own. But if I manually down shift bring the rpm up like a roll race and nail it the tps will follow my foot. This is a guess on my hp but I was out of fuel on 93 alone and running quite a bit of meth just to run E35 so feel like 700 whp is being conservative considering the car can trap the 140 range in the summer Florida heat. By redoing my e85 virtual torque I have the trans shifting faster then ever with out touching the tcm. So unless I can get 100 percent tps from a dig I see no point in paying all that money right now. I would like it to automatically shift at a higher rpm but for now will use paddles to make the 6600-6700 rpm shifts I have been doing. I just slap it at 6500 and it takes a good 100-200 rpm to happen as pulling so hard.

Could you elaborate on what you have done with the E85 virtual torque and how that has helped it shift better?

[lt1z350]

Could you elaborate on what you have done with the E85 virtual torque and how that has helped it shift better?

sorry just saw this. The car when it went over to the e85 maps was very lazy to shift way too soft under regular driving and lazy under wot. I figured it was the virtual torque possibly wasn't tuned due to not being a factory flex vehicle. So I used the edit function for virtual torque and pulled up the tables and matched them to my normal gas ones and they were low. So I looked at what was going to get them the same then added to them So don't remember exactly but think I raised the airmass by 25 percent and the map by 20 percent. If you raise them equally it will raise the delivered torque the same as the max torque and its possible to make it limit the throttle that is if it isn't already. I logged my virtual torque on the car then compared what I put in the table and went through and hand picked through it to make it match a little better on what the car though it should be making. Then smoothed it all and it has worked out very well on making the 10 speed rock the shifts even better now on flex then on gas.
You can go too high it gives this dead pedal feeling to it you nail it and get a flat feeling I have a log somewhere with it doing it but you can tell right away its too high as I did 30 percent at first and then added some to that without logging and changing. If you start in the 15 percent range it will be fine and not over shoot what it should be. I have a really good set of channels and layout for it all with the xml for virtual torque and virtual hp if needed. Needless to say I have all this and still cannot get my idle timing back up to 12-16 degrees with my larger throttle body on the car now and been stuck at 2-6 degrees and has a lazy idle now I cannot tune out.

[TriPinTaZ]

sorry just saw this. The car when it went over to the e85 maps was very lazy to shift way too soft under regular driving and lazy under wot. I figured it was the virtual torque possibly wasn't tuned due to not being a factory flex vehicle. So I used the edit function for virtual torque and pulled up the tables and matched them to my normal gas ones and they were low. So I looked at what was going to get them the same then added to them So don't remember exactly but think I raised the airmass by 25 percent and the map by 20 percent. If you raise them equally it will raise the delivered torque the same as the max torque and its possible to make it limit the throttle that is if it isn't already. I logged my virtual torque on the car then compared what I put in the table and went through and hand picked through it to make it match a little better on what the car though it should be making. Then smoothed it all and it has worked out very well on making the 10 speed rock the shifts even better now on flex then on gas.
You can go too high it gives this dead pedal feeling to it you nail it and get a flat feeling I have a log somewhere with it doing it but you can tell right away its too high as I did 30 percent at first and then added some to that without logging and changing. If you start in the 15 percent range it will be fine and not over shoot what it should be. I have a really good set of channels and layout for it all with the xml for virtual torque and virtual hp if needed. Needless to say I have all this and still cannot get my idle timing back up to 12-16 degrees with my larger throttle body on the car now and been stuck at 2-6 degrees and has a lazy idle now I cannot tune out.

Are you saying any increase in Airmass Virtual Torque increases Maximum Torque? And increases in MAP Virtual Torque increases delivered torque?

[HeavyChevy305]

Are you saying any increase in Airmass Virtual Torque increases Maximum Torque? And increases in MAP Virtual Torque increases delivered torque?

Engine<Torque management<Engine<Torque coefficients<EQ Ratio Based. That's the table I messed with to get the torque models to line up better.

[TriPinTaZ]

Engine<Torque management<Engine<Torque coefficients<EQ Ratio Based. That's the table I messed with to get the torque models to line up better.

Which torque PID does that affect? Delivered and Predicted TQ?

[HeavyChevy305]

Which torque PID does that affect? Delivered and Predicted TQ?

All of them. That table tells the ecm how much of the coefficients to actually use to calculate.

[TriPinTaZ]

All of them. That table tells the ecm how much of the coefficients to actually use to calculate.

I'm still curious what was so out of line to need to adjust this that Virtual Torque, DD, and torque limits wouldn't fix? Or did you just want the reported torque to be more accurate in your logs?

[HeavyChevy305]

I'm still curious what was so out of line to need to adjust this that Virtual Torque, DD, and torque limits wouldn't fix? Or did you just want the reported torque to be more accurate in your logs?

My commanded torques were always a bit under (-6/7ft.lbs) my delivered even though my air models are correct. Lining them all up helps my auto tranny more than anything.

Reason I went this route is because I honestly have no clue how the virtual torque table edit works. My torque models all follow each other, just -6/7 ft.lbs low. I just told the ecm to use 2% more of the coefficient calculation at lambda and WOT because it uses less than 1.0000 from the factory.

[s57_s2k]

What does it means when Predicted Engine Torque Source switches from "axle" to "chassis" at the end of a run ? I turned off the traction control and the problem went away

[TriPinTaZ]

What does it means when Predicted Engine Torque Source switches from "axle" to "chassis" at the end of a run ? I turned off the traction control and the problem went away

I think that means the chassis control module is intervening with the delivered torque value. Could be traction control kicking in or your torque model could be off and exceeding the traction control torque limit.

[lt1z350]

I have a good write up on the virtual torque but it?s easy once you know what the values mean. Log your cam data so know where the retard it at during wot that goes in the cam box. Your timing I would tune 0-40 tables and the airmass at the top. If your boosted your over 1000. If n/a just put 0 in first cell and 1000 in second the value is cylinder airmass like your timing table. Just not using the decimal. That will give you full range to adjust on them for the vehicle. I could give you a channel list you send me a log and I could most likely tell you what?s going on.

[cmitchell17a]

I have a good write up on the virtual torque but it?s easy once you know what the values mean. Log your cam data so know where the retard it at during wot that goes in the cam box. Your timing I would tune 0-40 tables and the airmass at the top. If your boosted your over 1000. If n/a just put 0 in first cell and 1000 in second the value is cylinder airmass like your timing table. Just not using the decimal. That will give you full range to adjust on them for the vehicle. I could give you a channel list you send me a log and I could most likely tell you what?s going on.

Thanks for the info! I just relooked at my torque tables and they are actually identical for E85 on both MAP and Airmass based. I was thinking they were different but I guess I was wrong, but I didn't thoroughly check every point. So I figure the official GM power rating on E85 is 8% higher, I'm assuming the torque calculation linearly interpolates based on the alcohol percentage to calculate the extra torque for blends. So I just multiplied the torque for all the cam advance and spark range by 1.08 and I'm going to see what happens. I was really thinking they were different between E85 and gas stock but I was wrong. I'm not sure if GM actually calibrated the LT1 for E85 I wouldn't think so, but I want to check the 5.3 truck tune and see what is different between the gas and E85. Sometimes when you look at what GM has done with the tunes you just get more confused when none of their changes make any sense.