I'd never rely on rear O2 logging - it always drifts with temperature. Serial logging is the way to go :thumbup:
This reminds me... I should add a function to Tuner Helper to use AFRMAP and AFR to calibrate the MAF and MAP. Won't work on Cobb logs (unless they've included AFRMAP) but still.No it's actually the best way, but for the sake of time and efficiency many of us use a large amount of narrowband O2 sensor feedback data to make the same adjustments.
Just make sure it's resulting in a smooth MAF curve. If it's no longer smooth and parabolic, you're probably going to start tuning in circles, so to speak. Often folks bake in adjustments to the MAF curve that ought be applied to both MAF and MAP calculations. This is why tools like Tuner Helper are so nice as they take into account the fact that the MAF curve should remain just that - a curve.
Here's a basic flow of my fuel model calibration process for a stock camshaft car:
1. Use well known or "close enough" fuel injector and MAF calibrations. This includes low pulsewidth adders, fuel injector scaling, injector lag time/latency, and MAF scaling.
2. Disable MAF calculations and rely on the factory MAP calibration to find out how far off your injector scaling is at idle and cruise. Adjust injector calibration accordingly.
3. Re-enable MAF calculation and disable MAP. Log several drive cycles worth of MAF Voltage, LTFT in use, and STFT and run it through Tuner Helper (thanks ripnet) to adjust your MAF curve. I run through this twice. Make sure to start with a sane MAF calibration that is either mathematically derived or taken from another car with the same MAF tube.
4. Disable MAF calculation and enable MAP calculation only. Use ripnet's tool to adjust idle and cruise the same way as for MAF calcs.
5. Set up your high octane AFR table to your desired targets. Use a conservative timing map and re-enable MAF. Start making partial and full throttle pulls and log MAF/MAP calcs, AFR target, and wideband AFR. Use this data to bring MAP calcs in the high load range closer to MAF calcs (always trust MAF calculation over everything else by default so long as you have no boost leaks).
6. After converging MAF and MAP calcs, start to use the delta between target and actual AFR to adjust the fuel calibration table ("VE" table in COBB) all around. The goal is to get MAF and MAP as accurate and tightly grouped as possible and then use the fuel calibration table to take care of any further inaccuracies in your fueling model. It affects all injection so it is not a VE table.
Then start tuning everything else
Is that the same step you use Rip?This reminds me... I should add a function to Tuner Helper to use AFRMAP and AFR to calibrate the MAF and MAP. Won't work on Cobb logs (unless they've included AFRMAP) but still.
So there's two different (maybe more) ways to accomplish this. Open or Closed loop. Currently, Tuner Helper is setup for Closed Loop, meaning it works on the STFT+LTFT fuel trim. Any values in the HOFM (AFRMAP) are ignored and irrelevant for this process.Is that the same step you use Rip?
I want to start doing this, or at least understand it.
Is this the correct summary?
- Plug in the rough numbers for injector & MAF
- Increase MAF to max value to disable it and have MAP only. Then follow Clipse's thread to get fuel scalings closer.
- Bring the MAF values back to where they were and max the values on the MAP tables to run MAF only. Log the car (assuming best drive would be city, and a cycle is 4-6min?). Then use those logs to run through Tuner Helper.
- Not really sure what this means.
- Since we're trying to get AFRMAP == AFR set your targets in the map. Use the data to adjust MAP to closely align (or match) MAF.
- Fix the difference between AFRMAP & AFR with fuel calibration table.
So there's two different (maybe more) ways to accomplish this. Open or Closed loop. Currently, Tuner Helper is setup for Closed Loop, meaning it works on the STFT+LTFT fuel trim. Any values in the HOFM (AFRMAP) are ignored and irrelevant for this process.
In a nutshell: TH looks at your logs and averages the fuel trim (STFT + LTFT) for each MAF voltage (or RPM/pressure cell for MAP tuning) and uses that average to determine the new number for that cell. For example, if at 2.6volts MAF, your combined fuel trims are averaging -6.25%, then it will multiply your current table value at 2.6volts by 0.9375. There's a few other calculations that aren't important, just know that they're there... like smoothing, running averages, zero IDC trimming, etc .
For this to work, the system you are working on (MAF/MAP) needs to be lower than the other. In the case of MAP, simply set your MAF table to it's highest value. For MAF, you'll need to set the MAP tables higher, but if you max them the car probably wont start. Multiply by 1.08 or something, just enough to get MAPcalc higher than MAFcalc. Alternatively, Cobb has the ability to shut off one system with a few checkboxes.
What I will add to TH soon, is Open Loop. This will ignore STFT+LTFT and use your wideband recorded value, compared against AFRMAP. TH will calculate the percentage difference, and adjust your map accordingly.
How do people do this now? Use the evo scan average tracer and just make adjustments by hand to the MAP tables to achieve desired AFR?What I will add to TH soon, is Open Loop. This will ignore STFT+LTFT and use your wideband recorded value, compared against AFRMAP. TH will calculate the percentage difference, and adjust your map accordingly.
RepliedOn my end I created a tool to do it but I sent a PM to ripnet maybe there's a way to merge a few thing or at least use the idea already done. That would save him time, coding isn't my job and I'm not good with user interface and error handling so what I did would never be usable by other people
Let's see maybe with his touch it can happen!