After lots a lots of research, conversation, and experimenting I believe I have gotten the hang of the first step in tuning. I'm gonna try and explain the best I can but feel free to add to the conversation or even correct me if I am wrong.
Tuning Step 1: MAF Calibration
As always the hardest part about learning something new is jumping in head first and learning. I've come across two methods on tuning the MAF and cannot find a great explanation between the two.
-Method 1: EQ Ratio vs. MAF Frequency
This method is the most commonly found when trying to research tuning. With this method you disable most calculations and tables in the computer.
Step 1: Scanner Setup
We need to setup a graph in VCM scanner to monitor EQ ratio vs the MAF frequency which I believe requires the hpt pro addon to interface with a wideband gauge directly but I could be wrong. You can also run a wideband signal to the AC pressure sensor wire on the ECU to log the AFR voltage in hptuners. This requires some extra math and wiring setup so let me know if you would like a write up on that.
Lets setup our Math via the Tools>Math Parameters>Maths-User. Choose one of the "User Math #" and setup the window like the photo:
*Note: the PID 50120 is shaded red because it is set to a generic sensor that the P12 ECM does not have. If you are tuning using hptpro with a wideband connected you will replace this PID with your WB
Once your custom math parameter is setup you can find your way over to the graphs tab in the scanner. Once there we will right click and go to "Graphs Layout". Once the graphs layout dialogue box opens we will add a graph and fill in the following fields:
*Note: The Values for the MAF Frequency were acquired by copying the axis from the MAF table in VCM editor
Step 2: MAF only setup
In order to calibrate our MAF sensor we need to make sure our car is only controlling fueling via the MAF readings. I have not personally used this method and do not know how the car will initially react untuned running on just the MAF so make sure to use your senses if it seems to be running poorly.
!!!!!make sure to save an ASFound file so if you need to go back to completely stock you can!!!!!
VCM Editor MAF only setup
Changes marked with a ** will be reverted post tuning. Make sure to take note of the original values
**Disable VE Tables**:
Engine>Airflow>Dynamic>Dynamic Airflow
High RPM Disable -> 300 rpm
High RPM Re-enable -> 200 rpm
Setting these will disable the Volumetric Efficiency tables, By disabling these tables the car will not adjust fueling via calculations using cylinder air mass.
**Force Open Loop**:
Engine>Fuel>Oxygen>ECT vs. Startup ECT
Set entire table to a coolant temp the car will not reach (I.E. 300 C)
Engine>Fuel>Oxygen>Delay
Set Table to a very large number (I.E. 5000)
Engine>Fuel>Oxygen Sensors>Monitoring> O2 Readiness ECT
Set entire table to a coolant temp the car will not reach (I.E. 300 C)
By forcing the car into Open loop it will ignore readings from the oxygen sensors and will run strictly off of the MAF tables to control fueling
**Disable Deceleration Fuel Cutoff(DFCO)**:
Engine>Fuel>Cutoff, DFCO>Deceleration Fuel Cutoff
Enable ECT -> 490 C
Disable ECT -> 480 C
Enable RPM -> 8192 rpm
Disable RPM -> 8191 rpm
Engine>Fuel>Cutoff, DFCO>Vehicle Speed
Enable Speed -> 300
Disable Speed -> 290
These settings disable fuel cutting off as you let off the throttle. This can cause burbles and pops while out driving should be ok so long as they don't seem to aggressive.
Now that our vehicle is set to MAF only we can start calibrating our MAF!!
Step 3: MAF Calibration
This portion is really important to the drivability of your goblin, Go out and do some driving but make sure to have VCM scanner running. Take it easy though, be very gentle on the throttle and try not to make drastic throttle changes and keep the rpm relatively low as our fuel is going to be way off for the first few runs.
Upon returning from your gentle drive make sure to save your log file. jump to the graph we created earlier, select the entire graph, right click and click copy. Jump back over to the VCM editor
Update MAF Calibration:
Engine>Airflow>General>MAF Calibration>Airflow vs. Frequency
Select your entire table, right click, select Paste Special>Multiply by % - Half
Step 4: Repeat
Continue the drive then MAF calibration until the error reported is less than 5% across the entire graph up to about 6000 Hz. Each time you calibrate the MAF you can start revving the engine out further but continue to keep inputs smooth and do not go WOT.
-Method 2: Fuel Trims vs. MAF Frequency
With this method you leave most tables enabled but disable dynamic airflow. I have been learning to tune under a well known tuner in the cobalt community and this is the method we have been using. However, I do not know or have an opinion on which method is better.
Step 1: Scanner Setup
For this method of tuning we are going to be using two different graphs to measure our fuel trims vs. MAF frequency.
Our first graph will monitor our STFT + LTFT vs. MAF frequency and is setup as shown:
*Note: The Values for the MAF Frequency were acquired by copying the axis from the MAF table in VCM editor
The second table we will be monitoring will use just the Long Term Fuel Trims like shown:
Step 2: Fuel Trim MAF Calibration Setup
This version of MAF calibration only disables Dynamic airflow and allows the engine to work in closed loop to determine what fuel trims make it happy.
**Disable VE Tables**:
Engine>Airflow>Dynamic>Dynamic Airflow
High RPM Disable -> 300 rpm
High RPM Re-enable -> 200 rpm
Setting these will disable the Volumetric Efficiency tables, By disabling these tables the car will not adjust fueling via calculations using cylinder air mass.
Step 3: MAF Calibration
This portion is really important to the drivability of your goblin, Go out and do some driving but make sure to have VCM scanner running. Take it easy though, be very gentle on the throttle and try not to make drastic throttle changes and keep the rpm relatively low as our fuel is going to be way off for the first few runs.
Upon returning from your gentle drive make sure to save your log file. jump to the graph we created earlier, select the entire graph, right click and click copy. Jump back over to the VCM editor
While doing our initial MAF tuning via fuel trims we will initially use the LTFT only graphs until we get close to the final product. Then we will start using our STFT + LTFT graph.
Update MAF Calibration:
Engine>Airflow>General>MAF Calibration>Airflow vs. Frequency
Select your entire table, right click, select Paste Special>Multiply by % - Half
Step 4: Repeat
Continue the drive then MAF calibration until the error reported is less than 5% across the entire graph up to about 6000 Hz. Each time you calibrate the MAF you can start revving the engine out further but continue to keep inputs smooth and do not go WOT.
I am far from an expert and have a lot to learn on tuning but I like to organize my thoughts when learning something new and figured I would share my findings. As I stated earlier if you see any errors in my documentation here make sure to let me know so I can update it!