how to populate empty cells by interpolation?

due to the elevation where I live (7000 feet in new mexico), I will never be able to populate the cells in the 88 & higher kpa cells in the 'manifold absolute pressure' table (like in the ltft).
now how would I interpolate the numbers for this cells (let's say if I ever drive to california or texas to sealevel elevation)?
I don't want the tune to be totally off in this kpa range.

look at the avg increase per row and continue the pattern.

some guys use a specific amount per row as well but I forgot what it is.

either way, bring your laptop and tune it again those numbers will only be a starting point.

Here is an old Excel work sheet I ginned up to interpolate VE. You take the values for the MAP/RPM you have logged and developed and populate the chart. There is 1 table in the HPTuner format and 1 in the EFILive format. Next to the chart is a little calculator which you populate with the VE value and MAP to start and the second is the farthest you got. You can set thes tables up anyway you like. Then insert the max KpA you want to poulate to and the calculator will give you the final value based on the slope of the data you inputted. Insert this value to your tune and use the interpolate function to fill in the rest of the row/column. Keep doing this till you have populated the entire tune table. Thsi will be a good (and safe) starting point for the Map higher MAP/RPM area's as you "sneak up" on them in you tune process.

As usual, this is not a certified program and should be used at your own risk.....sounds so lethal :)

Good luck

Ed M

thanks for the help & extra thanks for the excel sheet!