I figure some people have some type of timming controll systems. Lets get some info on what type of systems are out there and what is good and bad and also explain how advancing timming or pulling timming affects a motor.
Here is a break down of what I use and what is also popular in the w-body community. I use a IAT selector, which basicaly means it tricks the computer into thinking the Intake Air Temp. is what I tell it. In order for this particular unit to work timming tables must be “burned” or “programed” into the computer. This is not for beginners just loooking to turn up thier timing to make more power. Here is the write up on my particular unit and how it works directly from the manufacturer. Now I have a mild motor build up along with a water-to-air IC set up that drops my SC outlet temps considerably. I have 0 KR across the board with as much as 22 degrees advanced. Im also tunned and have timming tables programed to be able to run this safely.
The IAT selector contains a high quality 10 position selector switch. The switch is soldered to a PCB (printed circuit board) that has 10 1% SMT resistors on it. This provides the user with 10 discrete temperatures (70, 60, 50,40,30,20,10,5,0,-5 degrees Celsius). Due to the infinite number of possible PCM timing tables, the selector is labeled in degrees Celsius. These temperatures will correlate to additional timing advance beyond base timing to allow the user to add or remove timing within seconds.