Just had some interesting data points to add:
Fooling around with paired stock E-fans in the truck. It currently has one early 8 blade fan(Dr. side/stock position), and one late model 12 blade fan.(Ps. side/mech. fan position)
The early fan(8 blade) pulled aprox. 7.8 amps running
The late fan(12 blade) pulled almost 15 amps running
I didn't check start up amperage(ran out of daylight)
Based on the measured 50% higher start-up load on the Dirtbound fan, it wouldn't surprise me if the stock late mod. fan pulls over 20 amps at start-up.
Just using the subjective "hand in front of the fan" test, the late mod fan seems to move noticeably more air then the early fan. I suspect an actual flow test will show the early fan pulls about 2/3 to 3/4 the airflow of the late fan.
Truck sitting at idle:
Both fans running temp stabilized at 190(right at thermostat opening temp)
Running the late fan only, the truck would stabilize at idle at about 210deg.
Running the early fan only, the truck would overheat at idle: temp went to 220(aftermarket gauge)and kept climbing.
