Throttle closing, final throttle torque requested '18 Camaro SS

[Craig18SSA8]

Hey there everyone, i am having some issues with torque that i cant seem to wrap my head around.

When VTT tuning i was getting things dialed in when i began to get throttle closing as well as what looks like KR but torque management timing is at 0.0deg during the pulls.

I noticed that at the top of the pull where it closes the throttle and knocks that the "Final throttle torque requested" PID is dropping significantly while the care is trying to make more torque. For example that PID will say 383 and i will be making 444tq delivered.

What table adjusts this parameter? I would like to prevent any throttle closure during a pull as i will be finishing up my nitrous system soon and throttle closure during the pull can cause some issues.

TorqueLogThrottle close.hpl

496.9 peak TQ 4600 548.6 peak HP 6436 no ext load up 10 in low new tq 2 idle offset.hpt

[Craig18SSA8]

Anyone?? I can not figure this specific problem out.

[cmitchell17]

Can you get another log with the immediate and predicted torque source PID's logged? I am not convinced that is the usual throttle closure from driver demand being too low for airflow. You can try increasing drive demand torque at this RPM (or all RPMs I don't think there is really a ceiling you can hit that will screw up the ECM or flag anything). And I've tried to piece together all the torque PID's and what they mean and how they interact. I don't believe whoever named these had total understanding of the system either. They are not SAE PID's but proprietary GM PID's which we probably don't have the names of. I need to look on my imitation GDS tool to see what available maybe that would help cross reference what we can log in HPT, but either way this stuff is a nightmare of frustration and unknown timing/throttle reduction.

[Joshinator99]

I ran your entire pull and your TPS was 91.8 the whole time you had the pedal down, where during the run is your throttle closing? Sorry if I'm missing it.

[Craig18SSA8]

Time stamp is at 2:45:22

The throttle is absolutely closing. There are several TPS PIDs. The accel pedal, which is locked at 99.6, the TPS and tps desired both drop to %75 in this log. I bumped up the VTT tables a little more and the problem got worse. Final throttle torque requested is not changing in relation to the VTT changes. All other torque PIDs i have been able to get a result. This is really not making sense to me.

TM engine side is nearly completely disabled.

[Craig18SSA8]

Here is another log that shows how it is after bumping up the VTT more.

TorqueLogThrottle close 2.hpl

cmitchell17
Can you get another log with the immediate and predicted torque source PID's logged? I am not convinced that is the usual throttle closure from driver demand being too low for airflow. You can try increasing drive demand torque at this RPM (or all RPMs I don't think there is really a ceiling you can hit that will screw up the ECM or flag anything). And I've tried to piece together all the torque PID's and what they mean and how they interact. I don't believe whoever named these had total understanding of the system either. They are not SAE PID's but proprietary GM PID's which we probably don't have the names of. I need to look on my imitation GDS tool to see what available maybe that would help cross reference what we can log in HPT, but either way this stuff is a nightmare of frustration and unknown timing/throttle reduction.

I will add in more torque PIDs to see if there is something i am missing.

[luisdavid11]

increase your driver demand. the vss axis is in KM/h not MPH, that confused me and made it so difficult to tune but once I figured out it was in KM it was a breeze. Try it out

[Craig18SSA8]

Do I want to increase it in specific speeds? So far I usually grab all the cells in the 100 by x percentage, then the last two rows then the last three.

[Craig18SSA8]

Here is a log with all available torque PIDs
TorqueLogThrottle close 3.hpl

[cmitchell17]

I just increase the rows by a percentage thats constant across the speed axis, thats how the GMPP tune for the hot cam LT1 does it too. I see where the immediate and predicted torque request aren't changing on the throttle pull, but this kind of unknown torque reduction happens on GEN V's all the time and there's no explanation for it unfortunately. I would still increase driver demand tables and maybe try increasing the max torque tables too.

[luisdavid11]

yes wherever the throttles closing, check what speed in KM/h you were going and multiply that portion by say 20% or so and just smooth the rest

[Ben Charles]

The answer is NOT to just go in and blindly add a percentage to the DD... more to it then that. Can it work, yep! Does it make it right? NOPE!

[TriPinTaZ]

I don't see your Driver Demand Axle Torque Request being lower than Actual Axle Torque or Commanded Axle Torque, which would make me think it is not Driver Demand related.

Are you spraying nitrous when the throttle closes?

[Craig18SSA8]

I don't see your Driver Demand Axle Torque Request being lower than Actual Axle Torque or Commanded Axle Torque, which would make me think it is not Driver Demand related.

Are you spraying nitrous when the throttle closes?

The answer is NOT to just go in and blindly add a percentage to the DD... more to it then that. Can it work, yep! Does it make it right? NOPE!

I have not yet hit it with spray, hoping to solve this issue beforehand.

I did bump up DD a little bit more and was able to prevent it closing most of the time. However, it is still not perfect.

I did not have this issue until I bumped up VTT, I do not want to return to stock VTT as I absolutely had power on the table with stock torque tables. Any help from you guys is greatly appreciated.

[TriPinTaZ]

I have not yet hit it with spray, hoping to solve this issue beforehand.

I did bump up DD a little bit more and was able to prevent it closing most of the time. However, it is still not perfect.

I did not have this issue until I bumped up VTT, I do not want to return to stock VTT as I absolutely had power on the table with stock torque tables. Any help from you guys is greatly appreciated.

So the area where you changed your VTT means that it now references a different area of your Virtual Torque Tables. You need to go look at the values in VT where it USED to reference before you made the change, and then look at the values in VT in the new area that is referencing. Are the values in VT after the change higher or lower? This will likely be your answer. You need the NEW area to have values closer to the OLD area in VT so that the toque model lines up.