I may have missed this information, but does the implemented calculation for the resulting torque (Virtual Torque, that is) also include the effect of these tables (in Gen4)?
- EQ Ratio Based/EQ Ratio
- AC Torque/vs. AC Pressure
- AC Torque/vs. IAT
Data from a NA LS7 on hub dyno compared to ECM torque model. Torque model tables were untouched, hence the huge discrepancy with the real wolrd.
Last edited by barum; 04-12-2017 at 04:39 AM.
The trends seem to follow each other at least between reported and measured
Also consider one is a crankshaft torque model and one is wheel torque measurement. You have to factor drivetrain loss in there.
Jaime
Amazingly well considering how different the engine ouput is compared to stock. On the other hand, the airmass has the biggest effect on the torque so that's why the shapes look pretty similar.
Of course the error is not constant and I would not try to correct it with a fixed multiplier.
Probably pumping losses behave differently so I would put more correction effort on the rpm factor table.
Last edited by barum; 04-07-2017 at 08:57 AM.
It's not as I wrote above, it's the engine torque (estimated from a measured hub torque using 6% losses on Dynomite dyno).Originally Posted by ElecTech
Something is goofy with the Throttle Desired Airflow, the only time it seems to read right is when it is displayed in g/sec. kg/sec, kg/min, kg/hr all read exactly the same. It is the same with lb/hr, lb/min, lb/sec. And yet if you try to do math in g/sec, which seems to be the only thing that reads remotely close to your MAF reading the math comes out way off as if it is still reading in a different unit.
none of the Desired pids work, known issue
Has anyone ever seen them work in any beta version yet? I could had sworn I read a couple different instances where guys said that they were working. Will be sweet when they do work! Every time I update to a newer beta that's the first thing I go log and check. Lol.
2017 Silverado LTZ
I see how this all relates to predicted torque but I am still at a loss for finding information in regards to immediate torque commands. Does anyone have any insight as to how immediate torque is calculated and is it based off of these tables which only seem to effect predicted torque?
you are confusing naming for the torque management requests with the calculated engine torque (the topic of this thread). The link below explains it in some more detail.
http://www.hptuners.com/help/vcm_edi...vanced_e78.htm
I count sheep in hex...
Any chance that the pids will be fixed in the scanner Chris?
Which PIDs, which operating system, which VCM Editor version?
All the Throttle Desired PIDs in all the OSs in Beta
MAP, Airmass, etc
Please e-mail support an hpt file and a scanner log showing the issue.
No, I'm talking of how immediate torque requests are calculated. The link you post only says that immediate torque is related to things like spark and can be used to quickly adjust power.
The predicted request has a direct correlation to the VTT and you can see the outcome of your adjustments when scanning the different torque parameters but I have not found any direct correlation to any available settings and immediate torque requests. Not to say they aren't available and I'm missing them. But they tend to have a greater relation to actual engine torque.
The immediate (fast) torque request are basically anything that pulls timing or cuts fuel, the predicted (slow) torque request are anything that controls the throttle, boost or airflow related things like that. Each torque management requestor (eg. RPM limit, VSS limit, Axle torque limits etc.) has options for which methods it might use so the settings are usually per type. In the code itself the requests are often absolute requests or delta requests from the current calculated engine torque.
I count sheep in hex...
The predicted request follows the virtual torque tables, if I ask for 1200 ft/lbs at 4500rpm while I'm showing 800 on my airflow I will see a predicted torque of 1200 but the engine torque output will actually be following immediate request. Which might be around 450 ft/lbs.
Now if I go in and dial down my torque tables to 500 in the same range the next thing you know the immediate request is now reading 700 and the vehicle has a noticable increase in power.
I guess my disconnect is why does lowering the torque demands result in an increase in immediate torque requests resulting in a higher engine torque output?
The virtual torque tables aren't requesting anything, they are modeling the estimated engine torque.
I count sheep in hex...
torque demands come from the......Driver Demand table. ;-)
an immediate torque request would be from the driver demand table. "predicted" request would be from the torque model.
"He's asking for 450 ft lbs but the torque model shows I am making 700....I better limit power to give him what he wants!!"
It's all about a relationship between driver demand and the torque model. It almost seems like the numbers are arbitrary, as long as they relate to each other in a way that works, which is why I think I can leave it all stock so often and it works.....reported torque in the scanner might be wrong but does it matter when you are getting commanded spark, throttle, and fuel? Maybe only for an automatic transmission for shifting purposes but even then you could probably scale it.
I wonder if the torque model can be changed so that "100" is maximum value and then you can think in percents of power? Obviously everything would have to be changed, but if you used 100 in the DD 100 row and then used 100 your torque model for your max airmass and map cells, could you in theory scale and adjust the rest of the model accordingly?
But that doesn't make any sense as my DD tables are capped at 575 WOT and I am seeing 700 on my immediate torque requests and if I go in and raise the torque on my DD tables I actually see less torque output. Example, I was looking at a tune for another truck running basically the same setup, but his tuner ramped his DD tables up to 1200 (don't ask me why...) in WOT but his immediate never requests more than 450 and so his engine output is only hitting 450.
On my truck, trying two tunes with the exact same VTT tables I make more signigicantly power with lower numbers in the DD table. It's almost as if they inversely effect actual output. Hell, maybe I should zero them out, lol! At this point making any adjustments to anything that effects the predicted torque tables (VTT) doesn't seem to have any effect on actual output. Sure, it changes your logged predicted torque, but your actual output still follows the immediate request.
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