Quote Originally Posted by VanCo View Post
It's my understanding that when fully engaged clutch fans similar to the vans can pull 5000 plus CFM. Not sure if you have had the van super hot at 2500 rpm with the seat up and felt how much air is moved, but it's a lot.

Since the engine moves under load the stock shroud doesn't have a tight tolerance around the fan. This causes an inefficiency. Hence the overkill on the CFM. That's also why it is super important to have a good shroud with an electric fan. To make up for the lower CFM by being more efficient.

So far this radiator, shroud, and fan combo is better than any combo I've tried. Once the fan turns on at 198 it turns off at 190 within 8 seconds (switch set to 195). It will then take about 5 minutes for the fan to come back on. That's idling in a 70 degree garage (40 outside not a good test temp). The summer will be the ultimate test.

This is all based on my research and experience. If I'm wrong on anything, please correct me.
Vanco, all what you just said sounds correct (based on years of experience in the automotive industry). I have yet to see an electric fan able to move more air than a fully engaged clutch fan @ high engine RPM's (would draw too many amps and rob too much power). Efficiency can be dialed in though and the big advantage is they can run @ full output while engine is at rest. It will be interesting to hear how it does in the summer, please keep us in the loop. Tim