There is no timing retard unless .5 volts is applied to the "D" (white wire) on the four pin weatherpack connector.
With that .5 volts applied the ECU will go into "Limp Mode" retarding the voltage 10 degrees.
This function may or may not be applicable to boosted (turbo) systems, but I have not verified how much retard is needed for certain amounts of boost, or if the .5 volts is just on or off and not variable.
I would think it's on or off only, but I have not tested that theory yet.
