It is harder than that. The diameter must shrink, and it is not possible to just scale it down. The sensor diameter influences the trigger points, so the sensor output does not exactly track dimensions of openings and tabs. The electrical signal duration shrinks for openings, and extends for tabs. The ECU, is very application specific, so signals need to be very close to OEM, or there will be problems. Yes it is possible, you just have to understand sensing methods, and make adjustments, in ring design and or sensor choice.
