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Latest project ive been playing with is a 2011 dodge charger r/t with the 5.7L using HPT to add the LTFT values to the fuel map as a sanity check before adding heavier engine modifications. Typically a simple process however dodge uses an Artificial Neural Network(ANN) to control varying VE's depending on cam position(VVT motor so the cam swings). Only info if been able to find on modifying these tables has been on the HPT fourms seen here
setting up histograms is pretty straight forward but the fuel mass vs Inj PW and inverse table has me baffled as far as matching the adjustments in both tables. anyone have any insight or experience with this style of tuning? I would upload a log file and tune file but .hpl and .hpt isnt supported if anyone has a work around with that i have the files on hand.
I'm not familiar with tuning this particular vehicle and it certainly is a little different compared to most of the OE ECUs I reflash. It seems however that the process is primarily identical to scaling a MAF sensor and you've done the hard work of creating the histogram. From what I can see you just need to apply the percentage error into your InjPW vs Fuel Mass table. The Fuel Mass vs InjPW table is just the inverse of this table (I'm struggling to see why they need both but appears they do). The trick though is to then use the new values from your first table as the break points for the second table. Otherwise the breakpoints don't line up and you can't calculate the inverse value. I hope that makes some sense?
I may have the grasp of it, still having trouble uploading tune and log files so screen shots will have to do but the first attachment is the LTFT+STFT/fuel mass histo set with the same parameters as the Injpw vs FM table. When adding those values to the table should the multiply by % be used or the multiply by % - half option as seen in the 2nd attachment. With the inverse the way im interpreting what your saying is shown in the table comparison in the final attachment. The values are swapped between row header and tune values e.g. (inj pw table) row header 0 value 1, (fuel mass table) row header 1 value 0 and so on down the row. If that inverse is the correct procedure is there an import function on HPT? I selected row axis edit and then pasted copied values from Inj vs FM tables however the values in the table did not change just the row header values and the tune values had to be manipulated manually one at a time.
The ANN is, as stated, a way for the ECM to calculate volumetric efficiency in a "speed density" style way without having a gazillion VE tables. It's "sort of" like GM's virtual VE. There are a bunch of gains and mathematical expressions in there to help the ECU estimate the VE under some standard condition.
The difference between this method and a MAF scaling or VE table adjust is that this modifies the fuel flow calculation vs modifying the airflow calculation. The result is similar as far as changing fuel trims, but you won't be affecting the engine load calculation in the same way.
I know multiply by % - half option is used in virtual VE scaling on GM's.