Hi Dave, I'm wondering why are you filtering only closed loop data for WBO2 corrections? It doesn't make sense to me, as BLMs will change WB readout in CL.
I use WBO2 data from open loop AE and PE when the computer locks the BLM's to 128. CL WBO2 data will validate the corrections to the VE tables for rich or lean BLM's. A VE table causing rich or lean BLM's will also cause rich or lean WBO2 data in CL. BLM corrections have a limited ability to correct for rich or lean conditions. I've tuned several vehicles with AFR's. The WBO2 tuned vehicles run better, have fewer emissions, and achieve better MPG using CL WBO2 data.
dave w
I've always disabled CL when tuning with WB to prevent BLMs messing up the calculations. I've never thought about doing it in CL but I guess it can make sense. By the way, some ECMs still use BLM corrections in PE, but only when BLM>128
Firstly let me say thanks to everyone for contributing to this thread. I am working through this and making changes to my tune.
I am trying to understand what I am actually doing and where this will get me. I think that this spreadsheet will help get my VE tables “correct”. It does this by using WBO2 readings when:
- The computer is in closed loop
- The computer is in open loop AND the BLM=128
The spreadsheet finds areas where the tune is not at stoich and then either adds or subtracts from the VE% table. This will subsequently add or subtract fuel to move everything towards stoich.
Is what I said above correct? Please set me straight if I am wrong.
My expectation is that I will end up with a tune that looks something like the attached picture. But I could be wrong.
afrtable.GIF
So my biggest question is this:
- I do not understand how this process will get me to a tune that looks like the attached picture because it seems like this process is moving everything towards stoich.
BTW – I set the spreadsheet to 14.1 because all of the gas around me is E10.
Thanks,
MAC
There is a string of "Average IF" in the spreadsheet.
Average If, = Closed Loop
Average IF PE, = False
Average IF AE, = False
BLM's are not used and are Completely disregarded.
BLM's above 128 are lean.
BLM's below 128 are rich.
Increasing the VE table cell value (for example 2400 RPM, 70KPa) 68 to 78 will lower the AFR ratio (for example 15.2 AFR down to maybe 14.6 AFR, just guessing here to illustrate what will typically happen). Likewise if the BLM averages where 138 and changing the cell valve from 68 to 78 the BLM average will lower to 133, again just guessing.
PE is filtered to Average IF, PE = Active
To actually achieve 14.1, the Narrow Band O2 sensor voltages will need to be adjusted in the chip, which I've never done. The Narrow Band O2 sensor voltages are attempting to correct BLM's to 128 or 14.7.
I would first get the AFR's close to 14.7, then tweak the Narrow Band O2 sensor voltage to get the BLM's for E10 AFR.
Quite often BLM's and AFR's will contradict each other.
I like tuning with AFR, because the engine will run better than tuning with BLM's!
dave w
Wow quick reply! This helps. I will go back to 14.7 per your advice. Still not sure where this process is taking me.
When I am finished, will I have a tune that "makes power" by driving towards 12.3 at WOT and also runs fuel efficient by driving towards 15.3 (AFRs for E0 and as example) around cruise conditions (say 55 kPa and 1800 RPM)?
Basically what is the goal and final outcome of the tuning that this spreadsheet feeds into?
Stock engines with the stock chip are usually pleasant to drive and work well in a wide variety of driving conditions. Generally the stock engine and stock chip will have AFR ratios close to 14.7 +/- 0.5 AFR for a wide variety of driving conditions.
When an engine has been modified with performance parts, the stock chip does not provide a pleasant driving experience in a wide variety of driving conditions. Modified engines with a stock chip will not have 14.7 +/- 0.5 AFR's for a wide variety of driving conditions.
Modified engines need the Fuel Tables (also know as Volumetric Efficiency, VE Tables) corrected or re-calibrated to provide 14.7 +/- 0.5 AFR's for a wide variety of driving conditions.
The spreadsheet is a "Tool" that crunches the data log to show where the VE corrections are needed and calculates the required amount of change the VE table needs.
The spreadsheet is set up so the current VE Table in the .bin can be copy / pasted into the spreadsheet, then calculates the changes (from a data log using the current .bin file) so a "New" VE table can be copied / pasted into a new or updated .bin file.
Once the VE table is good, then it's time to adjust the PE and AE. The computer "Assumes" VE table is correct and adds extra fuel for AE and PE based on the VE table.
The spreadsheet will separate near idle VE and off idle VE when "Idle Flag" = ON.
dave w
Last edited by dave w; 05-30-2017 at 07:16 AM.
Hoping that it is okay for me to post these things here and that other folks new to tuning can learn from this. If I am out of bounds, mods feel free to delete/move.
- Will I be "done" with this part of tuning once I have everything in blue for "near idle no PE/AE" and "off idle no PE/AE"?
- I am surprised that my injector DC is so low. I upgraded the fuel pump. Pressure is around 13 psi. Does this chart (photo) "make sense" to you guys with lots of experience?Injector DC.jpg
- I am getting a lot of knock. How "bad" is this? How to I make it go away? (see picture)knock.jpg
- I am getting lots of spark advance at low RPM and high kPa. What does this mean? spark advance.jpg
- I am very surprised at how much I have decreased VE compared to the stock tune. Again does this "look right"? Could it be related to upgraded fuel pump? Picture shows the difference between the stock BIN and my current tune. VE Tuned vs Stock.PNG
- Last but not least I thought I would share my current WBO2 map from the spreadsheet. Got a long way to go. Comments welcome. Off Idle WBO2.jpg
Thanks,
AC
Your VE is set too low the tune is bringing your IDC way up when it gets bad the knock is going way up. The tune turns up IDC while the WB is leaning it out don't the forget it! Take your log time down on the wb first and if it's still cycling too fast raise your VE it most likely will stay up. Wait for Dave.
Brandon..
Last edited by De-stroker; 06-01-2017 at 10:43 AM.
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