I think u guys are doing something 'impossible'.

In ideal, alternator should be constant voltage source, which means it can provides infinite current for constant voltage. However in real world, when current draw increase, voltage will drop, this is unavoidable.

From my OBDII reading, during fan is ON, my vacuum will slightly decrease from 18.1 -> 17.8, throttle from 7.8% ->8.1%, while fuel flow will increase around 2-3cc/min, what does it mean? It simply mean during fan turn ON, alternator is supply large current to the fan, hence voltage is drop slightly. I guess ECU will instruct slight increase in fuel supply to bring up the engine speed, thats my observation on that. Maybe u guys think fan won't consume that much current. But try to think on it, our home stand fan consume around 58W in full speed, imagine our car fan during spinning the sound is so damn loud and fast, so u guess how much current needed for that? I dun know actual power consumption for our car radiator fan, but 58W for 14V need >4A current, if 100W how much? you calculate it (100W is underestimate i think). So unavoidable voltage drop will happen, even infinite point of GC added also won't solve ur problem.

The cabin light dancing effect that david20 stated is understandable where can be solved by GC, since it eliminates 'ground loop' problem (I attached file before).

So why put so much effort for just to 'eliminate' an issue that is impossible to eliminate? You are trying to change the law of electrical u know.

Anyway, anyone who installed oren ular, if u have multimeter, kindly measure the voltage drop across the GC cable.

The method of testing is by using mV scale on the meter, touch (-) probe @ battery (-) terminal and (+) probe to one end of GC cable (engine hook there). Ur engine must ON when u measure, pay attention not only to the numbering, but sign as well. Last month i tried re-route my current GC point to the engine hook on top of the exhaust manifold (open engine cover u will see got 2 engine hooks, one is near airbox, one is near mentioned place). What i measure is -11mV on my meter, which means the potential @ engine hook is even lower than battery (-), current is flow from battery (-) to engine block.   I tested other points @ car body, all shown (+) sign, this shown car body is not as negative as battery (-), and current is flow from the body to battery (-).