On the Nissans you can use the Consult I, II, or III to advance it through the PCM/ECM.
*If* you could do it manually and make the ECM accept the change, you would do it through the C.A.S./C.P.S. (Crank Angle Sensor or Crank Position Sensor) which is effectively tells the PCM where the valvetrain is in it's cycle and ergo, when to fire.
It's just a Hall Effect sensor utilizing a magnet and a pin.
Most engines have a range of acceptable initial ignition advance. Like for example 15 degrees BTDC with a +/- value or range of 2 degrees.
If that's the case, depending on the ron/mon value of gasoline you have available, you could possibly set the timing to 17 degrees *if* you use 93. (Advancing it 2 degrees beyond the factory spec)
If you live in Cali and only have 92, it would be prudent to stay with 15 or 16.
colnajoe's point is, if OE spec is, say 13 because of standard production variances, and you're running, say, 93, as 1911 states, you're not taking advantage of the higher octane (slower burning) fuel that the advanced ignition would utilize to make more power bottom end and midrange.
I don't give a fat baby f_ _ k about top end power on this application, I want bottom end and midrange grunt, and as much as I can get within reasonable parameters of the original design.
I would, however, reduce it to the bottom (13) or at most, midrange (14) of OE design when supercharging, providing there's not a replacement ECM with the upcoming blower. Even then, I would only want it *exactly* at OE specs.
Again, sorry for such a long post.
If anyone knows how we can adjust the timing, please chime in here. TIA
FWIW, I haven't researched what the spec timing is on this engine, I'm just using 13-15 as an example. That example is for a Nissan SR20DE(T)