Looking for input on tuning BLM Cell Boundaries

I've researched this topic a little bit and haven't found much. I understand why this would be important with cam changes, raised idles, and low vacuum idles. Most of what i found people tend to set the RPM boundaries as 1200/1800/2800or3000 and MAP boundaries as 50/70/90. also doubling the hysteresis for both RPM and MAP to 200rpm and 4kpa, which i see why to prevent unnecessary switching between cells.

To better understand the boundaries I took a simple datalog exported to csv and filtered out any data containg cells 16-18, 0% TPS, PE, cold temps. I then made a scatter plot of MAP vs. RPM and drew the factory boundary lines in red RPM 700/1200/2000 and MAP 32/50/80. Looking at this, one can easily see how the factory settings can compress a lot of driving conditions to a few cells while not touching others. (See Attached picture)

My goal in all this is to better spread the BLM cells over real world driving conditions in order to give the computer more resolution thus improving part-throttle driveability.

My questions are:
1.) I see why people don't bother to set the upper rpm limit any higher than 3000rpm as this also tends to be the cut off for VE tuning if you plan to switch back to a maf. conditions above 3000rpm you tend be in PE mode? and not part throttle driving, though this might not always be the case? So how high would it be safe to consider setting the upper RPM limit to better spread the BLM cells across real world driving conditions?

2.) For setting the lower MAP boundary should this go off of what your lowest idle KPa is? or a bit higher than this value?

3.) acceptable hysteresis settings for a larger-than-stock cam? I know many aftermarket cams tend to lope. so how much hysteresis is too little? how much is too much?

I'm all ears to any suggestions for RPM and MAP boundary or hysteresis settings or just any input that can help me understand the boundaries better.

Nice graph!

Looking at your graph, putting the rpm boundaries around 1500rpm, 2200rpm and 3000rpm would seem to divide the data up. 30, 45 and 60 kpa would also seem to divide it up the other way. This is just eyeballing the data trying to divide up the data evenly each way.

As for your question.
#1 - you still seem to be out of PE mode above 3000rpm for a fair bit of the time. But then, it thins out a lot above about 2800. So a boundary around that point does make sense. Then all rpms above 2800 are covered by 3 cells. I would think the BLM is correcting both MAP and MAF tables so that doesn't matter.

#2 - Pick the lower MAP boundary to divide cover 1/4 of the main operating range going vertical on your graph?

#3 - Maybe hold it at the different boundary rpms and see if it's showing signs of jumping between cells while driving conditions are stable?

Thanks Lionelhutz!

attached below is the same type of graph as last time but it has the updated cell boundaries I used to generate this new data.

the PDF is just a simple table that counts the number of times each cell was "hit".

it has definitely improved as now all 16 cells are utilized versus just a few.

The lower MAP setting I used of 45KPa seems a little high. Your suggestion of 30KPa as the lower bound is even less than the factory setting of 32KPa. With the factory settings it rarely ever touched any 0-32KPa cells .

Cell 1 is seeing way more hits than any other, so why don't you make that cell smaller. The top and right rows in your pdf are seeing few hits so you might as well lower those outer boundaries.

Did you setup the spreadsheet so you could vary the boundaries and see how it affects the number of hits in each cell?

I took your advice and made spreadsheet with variable boundaries to see how it affects each cell.

The trouble im having now is finding the right balance between spreading the cells evenly while maintaining boundaries that make sense. for example one of the best boundary settings in the spreadsheet yielded rpm boundaries of 1900/2100/2800 and map boundaries of 39/50/65.

Those map boundaries seem ok but only a 200rpm difference between low and mid doesnt seem correct even if it does spread them the best.

You can always try it a few ways and see if different settings actually make noticable a difference. Maybe compromise a bit and push 2100 a little higher and 2800 a little lower and go with it. In the big scheme of things, I would expect that if you get the VE and MAF tables fairly accurate that it won't make a huge difference where these cells boundaries are exactly anyways.

You're working on $EE, right?

yes this on $EE.

yeah in the grand scheme of things i know this isn't make or break, and seeing as how its already utilizing more cells ive definitely achieved my goal. I know its impossible to get a complete even spread between cells simply because theres certain RPM's & MAP's the engine is always going to operate more in versus others. I'll probably do one or two more revisions, then remind myself to stop being a perfectionist, call it good and move on.

thanks for your help and advice.