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Dodge tuning w/ ANN, InjPW v Fuel Mass, spark advance
Per several requests I'm going to attempt to explain how I tune w/ ANN on in some of the later model Mopars. By no means am I the "end all" of Dodge tuners. That is far from the case. There guys way smarter than me out there. I don't want this to turn into a ANN vs VE tuning thread. I just want to share a few basic concepts for Mopars and how they do their fueling. Most of this will be Hellcat related, but it applies to pretty much everything else. The process and the principles are the same.
Dodge uses F/A ratio instead of air fuel ratio. To find out what your stoich value is in normal terms, take 1.0 and divide by your FA stoich value, for a Hellcat it's .0722
1.0/.0722=13.85
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For WOT fueling Dodge uses multipliers that are added to the FA Stoich to achieve a desired value. To find out what your commanded WOT FA is, add your vs Aircharge vs RPM or vs PRatio vs RPM value to your FA stoich. Now these two tables are different and apparently the PCM uses both or either or but I have no idea under what circumstance. So I set both tables the same. I'm not saying that's right/wrong that's just how I do it. This is a screenshot of stock Hellcat tables.
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.0722+.0110=.0832
1.0/.0832=12.02 AFR
If you want to know what your commanded EQ is, 12.02/13.85=.87(rounded up)
To adjust fueling with ANN on you need to create a histogram for either STFT or STFT/LTFT if doing a Hellcat or Lambda Err if doing WOT tuning on anything else.
First look at your InjPW v Fuel Mass table. Make sure however you have it setup in Editor is the same way you are logging it in Scanner and have it setup in the Histo. I typically use grams
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In Scanner create a new Histo, select the STFT/LTFT(Math) parameter
For your Row axis select Fuel Mass Cyl 1(you should be logging it in the Channel in grams)
Take the InjPW v Fuel Mass column values and put them in.
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When you get done your Histo should look similar to this.
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Copy the Histo
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Paste into Editor
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Now this is important! You need to copy the injPW values and make the same changes in the inverse table, Fuel Mass vs InjPw. Now it use to be A LOT easier to compare these two tables prior to 3.2 but ever since then it's been a debacle IMO, but I digress.
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Reasons why your histo might not work
1. You are not logging the correct PID in Scanner
2. The units are not the same in the Channel as they are in the histo
3. Fuel Mass data not entered correctly in the histo
Exactly what are you doing tuning this way?
For any given Fuel Mass the PCM will open the Injector for a period of time to achieve that fuel mass. That's why it's a InjPW v. Fuel Mass table
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You use the STFT/LTFT to see how much the PCM is having to adjust to achieve it's desired fueling. It's no different than tuning a MAF. You adjusted your actual fueling to achieve your commanded.
You only adjust the InjPW, not the fuel mass. (There are some people that do but I haven't had to so far)