Hello Peep,
I can see how it can be confusing, it is annotated in the S54 trigger configlet in VT (but you would need to open the file with text editor to see it):
# Trigger settings for, missing tooth 60-2 primary, 8-1 secondary and 6 pulse third trigger for 6 cyl BMW s54 engine double vanos with full camsync
# Primary trigger VR
# Secondary trigger HALL: Exhaust camshaft (8-1 pulses) needed for cam sync
# 3th trigger HALL: Intake camshaft (6 pulses), needed for campos for intake cam
# Coils are dumb coils, need internal IGBT in v3.
# Dual VANOS needs 4 PFETS v3 inside to control it.
# Firing order: 153624
Reason for this requirement, since the intake cam has 6 even spaced pulses (3 in both exhaust and compression phase) there is no way to sync to that, the exhaust cam has a pattern which allows us to differentiate between exhaust can compression phase (3 pulses in one, 4 in the other) hence it is used for camsync.
Best regards, Dave