I asked about this maybe a year ago. Now that I've looked around the PCM tables I feel I may have found the tables I need to do it.

This could work for tuning MORE or LESS timing based off of a resistor in your coolant temp sensor. You could even wire up a harness that allows you to quickly switch between the resistor and the actual sensor.

First find the resistor for the coolant temp sensor that makes the PCM read -16 degrees C.

Then use the -16C tables for "Spark Correction vs. map vs. coolant temp"
Change that mostly to whatever your temp is that you normally race at but for the MAP values of your WOT you then alter that for your nitrous or race gas/timing advance. -4 or +4 or whatever you need.

Then you go through all the other coolant temp related tables (%change to afr/any start up coolant tables etc.) altering all the -16C cells for the operating/racing temp also, so that it acts like it should at it's actual temp.

Now, you've set up your PCM for normal timing with nitrous timing retard or race gas timing advance (more for boost guys)

No, I haven't tested this. But I don't see why this wouldn't work.

Only problem I see is you fools that start up your car in 3 degree weather (if you modify those tables).

What do you guys think?