effect of changing axis values in tables

[Gordon-0]

Possibly a stupid question but here is an example of what I am talking about.
Here is the idle spark table for my JEEP. There are 8 cells, but only 4 are used.
If a person wanted to try and use all 8 cells and gain a bit of granularity in the tune could they simply add values to the empty cells?
if this is not possible for whatever reason, could I instead simply change (for example) the axis value from 64 to (for example) 48 or something else?
Or are the axis values "read only" or hardcoded into the ECM even though you can technically edit them in VCM suite?

ThanksScreenshot 2024-08-12 201202.png

[smokeshow]

Looks more like a definition error to me.

[Gordon-0]

So if you are implying that there are only 4 actual cells in the tune then fine, but the question still stands.
Would it be possible to change the values on the axis and have those changes affect the tune or are the axis values "hardcoded" into the ECM?
if you click the axis label in VCM Editor you can change the values, I'm just not sure if those changes make their way into the ECM.

Here's another example.
In the critical spark vs ECT chart you can see that nearly half the values are "wasted" since from -40 to 20 they are all "5".
would it be possible to move the values up two rows and insert more values around the 95-100 range (where the thermostat actually holds ECT) instead of using 90% of the chart for values that don't matter at all?

Screenshot 2024-08-12 205923.png

[chevota]

You should be able to change them, but in my car I have to be wary. Most horz or vert scaling I can change just fine, but some end in disaster. Eg; I changed the fuel scaling to reflect the higher power, only bumping the bottom horz line like 15%, nothing else. I can't recall exactly what it did, but the fuel was so hozed it was undrivable and could barely idle. No clue why, but note to self; don't touch that.
Some things I'll change the horz or vert and later discover it also changed scaling on something else. No clue why, but any scaling I adj I have to look to see if that's all it changed.

In both those examples you posted I'd probably leave 'em alone. I completely understand if you just gotta, to see what happens, because I do exactly that. By doing exactly that I also learned most oem settings are fine. Another reason is every once in a while I'd tweak some little thing like that, then be haunted by an unrelated issue. Then at some point I figure out that spark tweak I did was hozing my fuel, or some misc turbo setting was hozing my idle. Just saying you might want to expect the unexpected, and if things go haywire, don't dismiss changes you did to completely unrelated things.
Yet another thing I learned is some things are simply not what they say they are. So you might adj your proportional spark in that first one, and find out it changes nothing at all, or something completely different, like throttle response or who knows what.
As for why the first one has zeros, I'd assume because it has 8 slots for data, by default, but they only needed three. Four technically because the 0 at the top is being used. I'd imagine you could just put all zeros except line two; 128= 16 and I seriously doubt you'd notice anything different. Or you could drag it out and use all the lines, but it would be pointless imo. It could also be possible that the last four are not active, so anything you put in them will do nothing.

The spark one you could adj it just as you described, and assuming it's actual degrees of spark that is straight up added/subtracted, it's probably fine where it is. You'd need to see how your engine runs at your air temp and altitude on the gas you're using to really dial it in. Odds are it's a bit conservative on the hot end, but only one way to find out.
As for the section that's all 5's, it's just more spots to put data than is needed. 20-120F is all that matters, apparently. So you could drag it out to use all rows, but I don't see the point. I'd just ignore it and focus on the real spark maps. Then I'd adj this one only if it needs adjusting thanks to the better main spark map. I'd probably go a step further and set the whole thing to 0 so I know it isn't upsetting my tuning, then go back and set it oem and adj as needed.

[LilSick]

short answer is yes... it can definitely make a positive change

although as stated you have to know where you can get away with it and where you cant

be careful in the vvt tables