There's no set value it changes timing. It simply tricks the ECU into thinking it's getting more or less air at a given RPM. This has the results of the ECU referencing the 'wrong' part of the fuel and ignition map. As for my settings, I've left everything at the zero adjust points. I'm not saying it's completely useless (it kinda works as a diagnostic tool, a poor one, and looks mad tight yo). But seriously, if you want a tuning tool then get with your 'tuner' and use what they recommend. If they recommend an SAFC then go somewhere else.
"The 300ZX Turbo is a dance; it's a song; it's rolling, roaring automotive art. There is no color that doesn't suit it. There is no mood-lifting chemical substance it can't replace." - Automobile Magazine
