In the meantime working on getting the car ready. Plan for this winter is ABS swap / brake upgrade, steering rack / electric power steering and fixing the top.
Today I was able to power up the ABS 5.7 unit in the wreck, connected to the rear wheel speed sensor of my real car. I was able to see the signal on the sensor and count the pulses, 48 in total as I was hoping (that's what the 986 uses, so I was guessing the 987 was the same). That confirms that the 987 rear setup is compatible with the 986 front setup
Next up was the speed signal (for my early intstrument cluster). At first no signal, so I assumed the output was open collector / open drain. Unfortunately a bit short in equipment at the moment, so I wired a few LEDs in series as a load. Voila, pulses on the ESO REAR output of the ABS module. I kind of was expecting a lower rate than the sensor, but it follows 1:1, so 48 pulses per rev.
Now I need to confirm that the ABS 5.3 does the same, but I am rather confident. Both ABS versions have a ESO (speed signal) with the same white / brown marking to drive the AHVAC module (something with automatic headlight leveling for the Litronics).
Next steps:
- Transfer the hardware from the wreck to my car. That is ABS 5.7, brake lines, bulkhead feedthrough etc. At the same time I'll swap out the brake hoses and fit the Boxster S calipers.
- Update the wiring in my car (sensor wires to the wheels, ABS 5.7 connector with power etc.). At this time I'll also prepare the wiring for the electric power steering pump.