[Jeff Chambers]

The computer has a fixed timing advance for any particular combination of rpm & load. For most stock computers (e.g. A9L), the maximum advance in the lookup table was about 17 degrees. With a stock base timing of 10 degrees, this gave a total timing advance of 27 degrees at peak conditions. Bump your timing to 16 degrees and the total advance becomes 33 degrees. The computer will not gain a 'wider range of adjustment' by moving the base timing..its still a maximum advance of 17 degrees; rather you've just shifted the entire timing band either up or down (advanced or retarded). Nor will it 'work backwards' to avoid detonation, the computer doesn't know what base timing you've given it. The computer also doesn't adjust timing at the distributor in terms of an advance curve like you'd get with the old spring & weight advances of mechanical distributors. It controls the the spark timing by internally (in the computer) delaying or advancing the coil signal relative to the Hall effect sensor mark and according to the total timing advance it has taken from the lookup table based on the engine rpm and load (which is a function of TPS position).

If you download the demo version of Autologic's chip software, you can get an idea of how the computer's program works in conjunction with the input its gathering from the various engine sensors.