Dan,
I just talked to Bruce about his engine. He said that he spoke with a Lycoming engine rep at Sun N Fun and was told that the max advance on the 390 with variable timing is 28*.
Incidentally, he has installed the SDS dual ignition system in it’s place, not the EFII system as I said earlier.
View attachment 20973
SPK. ADV. 20VAR - bottom row on data plate.
FALSE! The Lycoming EIS is fixed at base timing, configured by Lycoming...PERIOD. It is NOT advanced. If your Lycoming unit (Black) is advancing and not fixed, it has been tampered with. Therefore, there is no difference in unit behavior between a Lycoming EIS and a Surefly SIM in fixed timing.