MSefi.com read only forum (Jan.15,2018)

alpha-n qestion, when using alpha-n, you have your tps x rpm table, and fill in fake kPa values, when megasquirt looks at what kPa to reference in the VE table, what rpm column does it also go to? does it follow the same rpm as made in alpha-n table?

example:

tps 50%.................50kpa
rpm........800..........1200

in the VE table, I know it looks at the 50kpa on the left, but which rpm column does it go to? the first one or my 1200 rpm column to get the proper VE?

It goes to the column that represents the real RPM.

cool! if my alpha-n rpm column points (800-1200-1600etc) dont match my ve table rpm points (600-900-1200-1500)
does it interpolate a ve number between the two closest rpm cells?

Yes, like other tables, they're interpolated.

thank you matt, I did a test last night in which in my alpha-n table, i set my the cell my engine idles in to 20kpa, and on my vetable, at 20kpa, and the correct rpm, i set it around 47ve which my engine idles at with the map just fine, but with alpha-n enabled, it does not idle at all unless i raise my alpha-n idle cell to 65kpa, but in my ve table the 65kpa and 20kpa have the exact same VE numbers.
i can post pictures if this does not clarify

You've got to retune your VE table after you go Alpha-N, or anytime you make changes to the Alpha-N TPS table.

To get it to idle, you need to set whatever cell(s) in the VE table correspond to ACTUAL RPM, and FAKE MAP to the value that is appropriate for idle. So, it sounds like you need to make note of the VE value at 65 kPa (your S/D idle bins) and copy those values to whatever kPa bins you have set for the idle rpm range at zero TPS.

Once you get it to idle, you'll need to run through the whole autotune process just as if you were starting from scratch.