slvr7

iTrader: (1)

Interestingly enough, I have a couple AFM's on a home made test stand right now........
I'm comparing the outputs of an S4 & S5 AFM's at the same airflow level to see how 'swappable' they are.
I've got them both mounted on one end of a plastic pail (plenum), with a vacuum cleaner (actually two!) providing flow pulling air from the other end of the pail.
The AFM's are fed a ref voltage signal (4.7 volts), and I measure the Vsignal output with two multimeters. I alternately block the intake of one AFM while recording the voltage from the other.
So far, I've found that at rest (closed), and pushed wide open they return the same V to the ECU (3.7 and .38 volts, respectively).
At high airflow levels, returning voltages of under 1.5 volts, they return essentially identical values, within a tenth of a volt.
At low air flow levels, I'm having trouble getting results. The spring in the S5 meter seems stiff enough to prevent the cone from sliding away from rest position until the airflow is fairly strong. The FSM says at idle, it should be outputting 2.5 - 3.5 V, but when I get the S4 meter in that range, the S5 doesn't budge from 'closed'. However, it might be a problem with how I 'bleed' the suction to reduce the flow.
Other comments:
Air definitely has a much smoother, less turbulent path through the S5 AFM - the smaller input is probably offset by less drag on the air.
S4 flapper 'flutters' at lower airspeed - probably one reason for the revised meter design of the S5.

I'll post more results whenever I get some time.

Madrx7racer

NEW AFM question:

CAN I mount the S5 AFM at any angle????




CAn anyone explain why I found a pic of the AFM On the right side of the motor (looking from the front) with an FMIC set-up.......I'm used to seeing it on the end of the TID.......