Jimmy325i

It would be no different if the resistor values were identically linear, which they would not be in this case. The two afm's have different resistances for the same flow and therefore would not respond in a predictable manner across the spectrum. The only way you could tell if the s-afc would be able to correct for deviations would be to measure each's outputs for a number of air speeds at the same temperature and determine that they were in fact giving identical data representation back to the ecu, at which point the s-afc would not be needed.

Partial throttle, WOT, cruising, and heavy load conditions could not all be accounted for with simple afm correction by the s-afc if the two afm's didn't have very similar responses to the same volume of air. This is precisely why I said that you would be left with a narrow band of tuning going for correction this way.

If memory serves me right (I've been up for 19hrs and am too lazy to look right now) the S5's resistance is about 200ohms higher than the S4's at its max and 100ohms lower at its minimum. If nothing else that could overload the driver circuits in the ecu and then you'll be shopping for another one and another afm that will work correctly.

Anyone with a flow bench care to try the two out side by side? Take readings at different volumes and plot them out in an overlayed graph.