do a boost leak test. However you can go down to 12.0 but 11.5 is safe and when you are tuning it with the afc make it so that the graph gradually goes down if you are leaning it out or adding fuel. For instance at 1000 rpms you would take out 1% at 2000rpms 3% and keep going from there until you get to redline, until you get what you want on the higher rpms such as taking out 14% at 7000rpms and that should give you a good air fuel ratio for cruising. You do not want the air fuel ratio to be -10% at 1000rpms and plus 10% at 2000rpms. Also make it so that you can tune past 7000rpms on your afc that way if you ever go past 7000rpms it will be tuned for it. Hope this helps
