what parameters control Max Engine Torque values?

[cesar]

^^ This. And then you have to raise the Peak Torque Table and mess with Driver Demand as well. Max Torque is also affected by Max Torque Timing.

I know because it happened to me. I managed to increase the max eng tq BUT the predicted engine tq increased by the same factor so it's as if nothing happened everything just increased torque by a certain percentage even tho the airflow was the same. So the max eng tq by itself. What controls that?

[Higgs Boson]

here is a thread I started in 2015 on this topic....

Is this Limiting

[TriPinTaZ]

I know because it happened to me. I managed to increase the max eng tq BUT the predicted engine tq increased by the same factor so it's as if nothing happened everything just increased torque by a certain percentage even tho the airflow was the same. So the max eng tq by itself. What controls that?

There is no "separate" control to just make Max Engine Torque higher and nothing else. Max Engine Torque is directly affected by your Virtual Torque(Torque Coefficients) adjustments. I think you are missing the whole torque based logic. If you increase the Virtual Torque, then you have to increase the Peak Torque and then you have to make sure your Driver Demand Tables are commanding the right torque and line everything up so that nothing is limiting power and also that you are requesting enough power.

[cesar]

Then the tuning schools approach is completely and utterly redundant. They argue that the max eng tq shouldn't be exceeded by immediate commanded torque by any means. I can take a picture if needed.

[cesar]

To add to the discussion, what is the point of max eng tq if it's not a limiter?

[lt1z350]

I can tell you max engine torque is a hard limit. Tune a 2.0t camaro or ats. If the delivered engine torque crosses the max engine torque say good bye to your boost or watch the throttle close to at least 50 percent. To get a split on the max engine torque and delivered torque you have to raise both the airmass and map virtual torque. I raise one 15 percent and the other by 20 percent and that depending on vehicle split up the max from delivered more then if only raise one or raise both the same. I have had to play with this a lot on the 2017 and up turbo stuff to get my commanded boost to stay up which is directly related to max torque value on that car. So Im sure the same thing applies to others I haven't messed with yet.

[lt1z350]

also what I noticed in that other thread tps isn't being logged I have logs with etc at 100 percent and tps is at 68 percent. So that is a limit on the throttle if the tps isn't in the 92 percent and higher range. This all seems to be worse on anything that is boosted also. I never see any of these issues on anything n/a.

[TriPinTaZ]

To add to the discussion, what is the point of max eng tq if it's not a limiter?

Max Engine Torque must always be higher than Engine Torque or it is a limiter. Peak Engine Torque must always be higher than Max Engine Torque or it is a limiter.

That said, Driver Demand Requested Torque must always be higher than Immediate AXLE Torque Commanded and Actual AXLE Torque or it is a limiter.

The trick is getting these all lined up properly. If you increase the Virtual Torque which increases Max Engine Torque, then you have to increase your Peak Engine Torque to be higher than Max Engine Torque. Then you have to increase Driver Demand so that Driver Demand Requested Torque does not equal or drop below Immediate Torque Commanded or Actual Torque. If you plot these PIDs on a chart it becomes very obvious if something is limiting.

[cesar]

straight from BOB

"Just to bring you up to speed, the engine torque value you are speaking about does not necessarily have to be higher than the delivered torque (or even as high). I would recommend you only raise the virtual torque to the point that it's making the correct torque output and not worry about the engine torque. We are seeing some guys continuing to raise the virtual torque too high looking to get the engine torque up (even though it stops raising up). There are other limiters which prevent the engine torque from raising all the way up, but if you see the TPS staying open and the Spark at what you command, it's not an issue. The best bet is to ensure the virtual torque is raised only until the point that it is accurate for engine output - not crazy high.

Thanks,
Bob
The Tuning School Support Team"

Before VTT modification
before modifying VTT.PNG


After VTT modification
after modifying VTT.PNG

The MAX eng tq is less than the eng tq yet theres no pulling timing, or closing the throttle. Thats why I am confused. I attached 2 logs, before and after VTT modification. In both instances the max eng tq gets exceeded around same spots.

@lt1z350

I have read almost every single thread, and have seen your posts here and there. I am well aware of what struggles you have seen, I am assuming it is with that ATS turbo vehicle right? I noticed the pcm pulled boost AND timing if i remember correctly when max eng tq was exceeded in a screen shot of the log you had posted. So this is why I am trying to build on this discussion.
I have also noticed that modifying certain coefficients such as the MAP or airmass yields drastic changes even with the same amount of % added to the torque tables on the exact same spot. On this particular setup the change to the MAP yielding drastic changes to the MAX engine reported, whilst a change to the AIRMASS coefficient yielded minimal changes in max eng tq value. So max eng tq is a hard limit, why didnt it limit this vehicle on the log attached? In fact I have logged several trucks and they ALL get exceeded even factory. Straight up confusing when people say ignore it then others say dont ignore it and tune your VTTs.

@higgs

I've read super old threads trying to figure this out, you are always in them. Did you ever get to the bottom of this?

[Higgs Boson]

@higgs

I've read super old threads trying to figure this out, you are always in them. Did you ever get to the bottom of this?

IMO, there are simply not all the correct tables visible for us to properly tune these ECMs and until there are we will always be chasing our tails with this. After my 2015 thread I posted earlier I decided if the throttle is staying open, spark is as commanded and fueling is correct, we are simply not being limited, regardless of what all the torque pids are.

after I started tuning ecoboosts and drawing similarities in boost control logic, I also think the torque pids w/respect to limiting has a lot more impact on (stock) turbo applications.

what I really don't like is the throttle opening up significantly more than pedal command (since the pedal doesn't command the throttle, only a torque request), I don't want to give 40% pedal and get 90% throttle, so I tune for that if I can, most of my current gripes are with part throttle, not WOT.

To make matters more interesting, I had a 2014 Corvette a few years ago with a 416ci and a blower flowing around 900 lb/min, I kept the entire DD table stock (and this was before we had virtual torque calculator), Peak Torque stock, etc and had no throttle limitations as long as fueling was in line. It would pull spark at WOT though, but not due to knock however there was no actual power loss incurred. Had LT4 pump and injectors and meth injection.

My current tinker car is a 17 Z06 that is currently getting a cam and a whipple with a port injection system. Hopefully the hardware will be complete by this weekend and I will get some good tuning info out of it, especially since I plan to leave the MAF curve stock and add fuel only with the port system.

[Brianw36]

TPS isn't being logged for a reason, ETC Pedal and ETC Average are being logged for a reason.

read this: https://www.hptuners.com/help/vcm_ed...vanced_e78.htm

TPS is a pid for old cars and trucks, you're logging the wrong pids.

I have a 2016 Camaro i just looked at hptuners and i don't see where i can find those pids. Could you share where they are found. Thanks

[Higgs Boson]

I have a 2016 Camaro i just looked at hptuners and i don't see where i can find those pids. Could you share where they are found. Thanks

add channel and type ETC in the search box

[Brianw36]

I did that and it only shows etc reduced power [No/Yes] etc reduced power [No/Yes] etc forced idle [No/Yes] HPTuners Version 4.0.12

[TriPinTaZ]

straight from BOB


Before VTT modification
before modifying VTT.PNG


After VTT modification
after modifying VTT.PNG

The MAX eng tq is less than the eng tq yet theres no pulling timing, or closing the throttle. Thats why I am confused. I attached 2 logs, before and after VTT modification. In both instances the max eng tq gets exceeded around same spots.

@lt1z350

I have read almost every single thread, and have seen your posts here and there. I am well aware of what struggles you have seen, I am assuming it is with that ATS turbo vehicle right? I noticed the pcm pulled boost AND timing if i remember correctly when max eng tq was exceeded in a screen shot of the log you had posted. So this is why I am trying to build on this discussion.
I have also noticed that modifying certain coefficients such as the MAP or airmass yields drastic changes even with the same amount of % added to the torque tables on the exact same spot. On this particular setup the change to the MAP yielding drastic changes to the MAX engine reported, whilst a change to the AIRMASS coefficient yielded minimal changes in max eng tq value. So max eng tq is a hard limit, why didnt it limit this vehicle on the log attached? In fact I have logged several trucks and they ALL get exceeded even factory. Straight up confusing when people say ignore it then others say dont ignore it and tune your VTTs.

@higgs

I've read super old threads trying to figure this out, you are always in them. Did you ever get to the bottom of this?

Looking at your logs, neither one show the Maximum Torque dipping that much below Engine Torque. Maximum Engine Torque has to go quite a bit below Engine Torque for it to limit power, but apparently this isn't always true depending on the ECU And GM vehicle or at least there is a different threshold for being "over/under the limit". It's freaking weird. If you're not being limited at WOT then its not really a problem. If Engine Torque was much higher than Maximum Engine Torque during a WOT run it would likely start pulling power.

Pretty sure that Peak Engine Torque is a hard limit vs Maximum Engine Torque for all E78/e92 ECU's. But tuning is not my day job, rather a hobby that I've been doing since the late 90's when LT1 Edit was the only thing around.

On my 2015 C7, my Engine Torque never exceeds my Maximum Engine Torque. I've read some tuning material on the GenV stuff and it says increasing the Virtual Torque should increase Maximum Engine Torque above Engine Torque. Have you tried to increase your VT tables even more to see? Also, did you start with completely stock Coefficient Tables and only use the Virtual Torque Editor to make changes? Have you touched Max Torque Timing table at all?

[Ghostnotes]

Max Engine Torque must always be higher than Engine Torque or it is a limiter. Peak Engine Torque must always be higher than Max Engine Torque or it is a limiter.

That said, Driver Demand Requested Torque must always be higher than Immediate AXLE Torque Commanded and Actual AXLE Torque or it is a limiter.

The trick is getting these all lined up properly. If you increase the Virtual Torque which increases Max Engine Torque, then you have to increase your Peak Engine Torque to be higher than Max Engine Torque. Then you have to increase Driver Demand so that Driver Demand Requested Torque does not equal or drop below Immediate Torque Commanded or Actual Torque. If you plot these PIDs on a chart it becomes very obvious if something is limiting.

I was making some progress on my own but went ahead and bought the books as well. It actually put things into perspective. I stated in other posts that I knew what I wanted to do, but not the how. They have cleared a lot of things up. and this statement makes TONS more sense now. The books are not a walkthrough, not even close but for me they have helped me progress.

[TriPinTaZ]

I was making some progress on my own but went ahead and bought the books as well. It actually put things into perspective. I stated in other posts that I knew what I wanted to do, but not the how. They have cleared a lot of things up. and this statement makes TONS more sense now. The books are not a walkthrough, not even close but for me they have helped me progress.

The one thing to note is that not all of these things are hard limiters. Some start limiting in some fashion if you get anywhere close to the limiters value. Some actually let you cross beyond the limiter somewhat before even starting to limit. And it can also be confusing because sometimes the limiter will impose Torque Management Advance to reduce spark to lower a delivered torque request. And sometimes it will close the throttle. And then others it will do both. So it really is about knowing the lower limits and the upper limits and fitting everything in between.

I agree the GenV tuning material was ambiguous and would not be very helpful to anyone who doesn't have past experience tuning. The way the book was written assumes you already have a high level of experience tuning. So for those of us with the experience, it did fill in a couple of uncertainties and questions. I still think there are tables yet to be accessed by HPTuners that could make tuning GenV easier. Specifically, Torque Management limiters and such. I wonder if they will ever be found.

[cesar]

If I remember correctly a member here, jarrah, mentioned that there are missing tables in which the PCM can be commanded to reference actual map and actual MAF values instead of trying to reference desired MAF and desired throttle map values (that would hinder or limit timing, throttle angle). This table does exist and is used by GM engineers at the beginning to map out the various tables in the CAL. It would ignore all torque PID error changes and just go off of actual maf and map. With this table I would assume that these controllers wouldn't be no different than a e38.

[Ghostnotes]

If I remember correctly a member here, jarrah, mentioned that there are missing tables in which the PCM can be commanded to reference actual map and actual MAF values instead of trying to reference desired MAF and desired throttle map values (that would hinder or limit timing, throttle angle). This table does exist and is used by GM engineers at the beginning to map out the various tables in the CAL. It would ignore all torque PID error changes and just go off of actual maf and map. With this table I would assume that these controllers wouldn't be no different than a e38.

I also read somewhere recently in a post that there are well over a thousand tables (if I remember right).

[Wheeler]

I did that and it only shows etc reduced power [No/Yes] etc reduced power [No/Yes] etc forced idle [No/Yes] HPTuners Version 4.0.12

I am using VCM Scanner 4.0.12 and I have the same issue ETC pids.

[TriPinTaZ]

I am using VCM Scanner 4.0.12 and I have the same issue ETC pids.

On some vehicles it is called Accelerator Pedal Position