R51/2 ignition and gasoline octane grade

[Ivo]

Based on the manual of the R51/2, the ignition settings should be 38° to 41° v.o.t. for early ignition position and 12° v.o.t. for retarded position. This for gasoline with an octane grade of about 70 at that time.
Does someone know what these settings should be for todays 90 octane grade?

Ivo

[Ivo]

" todays 90 octane grade" should be " todays 95 octane grade"

Ivo