Jim makes an excellent point. Granted a relay is a relay. Either works or not. But the efficiency of different relays is the question. I am of the impression that the PCM sends ground to the relay until oil temps reach a certain level. That may not be correct but that is my assumption. Like the IDI engines and coolant temperature.

If you fired up and went to high idle immediately I can see the higher voltages coming into play. Even though for a very short time.

Gonna have to do some more thinking on this one.