Peak Torque vs Driver Demand

[MarkTucker]

Should Peak Torque always be higher than Driver Demand?

Example: Stock 2021 Camaro SS, manual (photos below)
Stock Peak Torque Values.png
Stock Driver Demand Values.png
Peak Torque vs Driver Demand.png

From the screenshots, you can see that almost the entire Peak Torque table is higher than the 100% row of the Driver Demand table.

So when adjusting the Peak Torque table after modifications are made to the vehicle that has increased the power output, should the Peak Torque table always be higher than the Driver Demand to follow how the stock calibration is? I have seen people state to make the 100% row of the Driver Demand table the same as the adjusted Peak Torque table (at least the highest value from this table). And then I have seen other's that have the 100% row of the Driver Demand table set higher than the Peak Torque table.

What is correct?

[TriPinTaZ]

Driver Demand is a request for torque. On some cars, Driver Demand is actually newton meters and not ft-lbs. Same with the Virtual Torque table. That said The Peak Engine Torque table is not a limiter for Driver Demand from what I have found. Meaning you can request Driver Demand to be higher than the Peak Torque table, but that doesn't mean the Engine can give it to you. Peak Torque is more of a limiter for calculated torque from airflow. Multiple things can influence calculated torque.

Is there an issue you are having?

[Alvin]

Should Peak Torque always be higher than Driver Demand?

Example: Stock 2021 Camaro SS, manual (photos below)
Stock Peak Torque Values.png
Stock Driver Demand Values.png
Peak Torque vs Driver Demand.png

From the screenshots, you can see that almost the entire Peak Torque table is higher than the 100% row of the Driver Demand table.

So when adjusting the Peak Torque table after modifications are made to the vehicle that has increased the power output, should the Peak Torque table always be higher than the Driver Demand to follow how the stock calibration is? I have seen people state to make the 100% row of the Driver Demand table the same as the adjusted Peak Torque table (at least the highest value from this table). And then I have seen other's that have the 100% row of the Driver Demand table set higher than the Peak Torque table.

What is correct?

I think that its done this way to ensure the ECM is trying to get everything possible at wide open throttle. If your asking for less than what peak torque is set to than throttle and advance might be modulated. if your asking for more than whats in the peak torque table and torque model for that matter your ensuring full advance/throttle.

Seems like good practice to always ask for more than what the modules/peak torque are set to.

[TriPinTaZ]

In a nutshell, if you increase the airflow which in turn increases the calculated torque, you will need to increase the peak torque. In turn you will then need to increase the Driver Demand so that you actually request the newly available increased torque(calculated from airmass). You can request more than available which won't cause any issues but may make the throttle too jumpy. On the flip side you could adjust Virtual Torque to trick the ECU into thinking its making less torque, then the stock Driver Demand and Peak Torque tables will not be out of range. In some scenarios and setups, you would actually do the opposite of what I just said because calculated torque drops below stock values. This is one of the ways the Automatic Transmissions start having issues with shifting and strange behaviors.

If your car is indeed stock and you are looking for better throttle response, just do some minor increases to the Driver Demand table. There is no need to touch peak torque. It won't do anything.

[MarkTucker]

Thank you both Jason and Alvin for the information and experience.

I do not have any current issues with this vehicle. Only asking to understand better. As I have seen it done each way (PT lower than DD, PT same as DD and PT higher than DD) and wanted to hear which is correct.

As far as the DD table referencing Nm instead of ft-lb. How did you determine the unit of measurement? As if you hover on the table with your curser, it just shows the min/max allow values (-500,000 to 500,000) without unit of measurement.

[Alvin]

Be aware that peak torque table influences when PE is activated (% torque)

Its a common mistake to max that table.. then the ECM will never go into PE

[MarkTucker]

Alvin,

Good tip.

I have been told not to simply max the peak torque tables.
My common practice has been to increase the areas typically above 2,000/2,500 rpm (leaving the areas around idle stock values) by a certain percentage based on the modifications and expected power gains from said modifications. But I have also have been increasing the top end of the driver demand tables by the same percentage, which most of the time does not put the driver demand table higher than the peak torque tables.

So with your advice from above, I will experiment with increasing the driver demand tables to a higher value than the peak torque tables and compare the results.

[TriPinTaZ]

Thank you both Jason and Alvin for the information and experience.

I do not have any current issues with this vehicle. Only asking to understand better. As I have seen it done each way (PT lower than DD, PT same as DD and PT higher than DD) and wanted to hear which is correct.

As far as the DD table referencing Nm instead of ft-lb. How did you determine the unit of measurement? As if you hover on the table with your curser, it just shows the min/max allow values (-500,000 to 500,000) without unit of measurement.

Virtual Torque Tables are referenced in Newton Meters. I don't know why Driver Demand and VT is in NM but other stuff is in FT-LB. In Automatics the Driver Demand is measured in torque at the Axle vs the Engine. It is what it is.

There is no "correct" way I suppose. When you start tuning complicated setups, sometimes you have to trick some areas to play nice with others. Generally you want to keep things in line. The main driver of modifying torque settings anywhere is airflow/airmass. Since the ECU calculates torque from actual and/or estimated airflow.

[02402ramair]

Virtual Torque Tables are referenced in Newton Meters. I don't know why Driver Demand and VT is in NM but other stuff is in FT-LB. In Automatics the Driver Demand is measured in torque at the Axle vs the Engine. It is what it is.

There is no "correct" way I suppose. When you start tuning complicated setups, sometimes you have to trick some areas to play nice with others. Generally you want to keep things in line. The main driver of modifying torque settings anywhere is airflow/airmass. Since the ECU calculates torque from actual and/or estimated airflow.

I can change the units in Virtual Torque from NM to FT-LB. Am I missing something here?

[Tunercharged]

I’ve just upped my DD table by 1.25 for middle 4 rows and by 1.5 for the rest, leaving the lower ones stock. It has made it more responsive to throttle which I can feel. I’ll have to scan some pulls to see what differences there actually are. Except for tuning, my engine is stock.

[TriPinTaZ]

I can change the units in Virtual Torque from NM to FT-LB. Am I missing something here?

Nope, pretty sure most of us switch Virtual Torque to ft-lb to make everything easier and match up with everything else.

[TriPinTaZ]

I’ve just upped my DD table by 1.25 for middle 4 rows and by 1.5 for the rest, leaving the lower ones stock. It has made it more responsive to throttle which I can feel. I’ll have to scan some pulls to see what differences there actually are. Except for tuning, my engine is stock.

That is what increasing Driver Demand does. If you increase the numbers, the throttle blades will open sooner/faster starts at lower gas pedal positions to provide what it thinks is the driver is asking. The car will not be any faster at WOT and nothing else will change.