Why do people replace ACD with viscous coupling?
Evolved Member
Joined: Mar 2008
Posts: 2,110
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From: Croatia
According to the evo 9 wiring diagrams the AWD Controller takes direct input (spliced into the same outputs) from the TPS sensor, Steering angular velocity sensor, G-Sensor (Longitudinal), G-Sensor (Lateral), parking brake switch, and the stoplight switch. All the wheel speed sensors are wired directly into the ABS Controller. There are then what appear to me to be 5 data wires connecting the ABS Controller to the AWD Controller. There is one wire going from the AWD Controller to the ECU.
I'll post the diagrams if anyone is interested.
I'll post the diagrams if anyone is interested.
yes but you can wire the wheel speed sensors into the 4wd ecu and run it without ABS if nedeed
EvoM Community Team Leader
Joined: Aug 2005
Posts: 5,690
Likes: 708
From: West Coast
EvoM Community Team Leader
Joined: Aug 2005
Posts: 5,690
Likes: 708
From: West Coast
I found the diagram for ACD w/out ABS, the speed sensors are wired directly into the AWD controller, and they match 4 of the wires that are connected to the ABS. C-139 Pins 6,7,8,9. So its almost certain that the ABS controller is just passing along the sensor signal to the AWD controller. No clue on that fifth wire though C-138 pin 48, seems absent from the Non-ABS diagrams.
I cant speak too much for the acd alone but i know autocrossing my X i was overwhelming the acd/ayc system. The diffs would screech and howl on aggressive corner exits or just unload all together after a few seconds and make the car push hard. Its nice to have but i feel that it loses a bit of its effect once big tq, corners, stiff spring rates and big hoosiers come into effect.