i tune with zero IAT correction but will usually add fuel above 50C and ramp it up drastically, intake temps much hotter will greatly increase knock so it acts as a detune safety measure. i never really noticed IAT affecting the tune enough to tune it. water temp on the other hand, quite a bit more important and generally relates to IAT, so technically you could use either or but water temp is more accurate.

 

What about for cold air? Where do you start adding fuel?

 

air mass calculation........... manifold pressure is only part of the equation
.. IAT maps is to give some correction to account for density changes

you add fuel when they get hot...not because of density correction ,, where the correct alteration is actually to pull some fuel ,,.... for safety margin against detonation when pressed at high temps
if you have timing correction for AIT,, then also pull a degree or two out when inlet air temps push beyond 80 C

however,, is EXTREMELY handy for density correction when IAT dips low,,, again adding fuel to correct the density to prevent a lean out on fresh cool mornings


the normal operating range for IAT should be relatively flat or zero in the bin values

 

i don't. west coast never gets below freezing which so far i have not run into an issue from summer to winter tunes. even WOT, stone cold, mid winter i have never had an issue just using coolant maps for corrections. (no i don't recommend going WOT on a stone cold engine but personally i could care less since i can just toss another motor in my car)