Run electric fans all the time?

cudajames said
Interesting. I've recently changed to electric fans and still dialing it in

Currently my puller fans run all the time - freeway etc. So if I am understanding this correctly, at speed as the outside air pushes into the radiator the turning fans become an obstruction on the air passing through? Controlling the fans, so they are not running at speed, helps with the air passing through?

goldduster318 said
Its safer to say its not doing any good running them at freeway speeds. If your radiator is correctly sized, you should be able to drive 45mph forever and never have them turn on even on the hottest day.

Exactly. It's like I said earlier. At best, running the fans when the car is moving at speed is a waste of energy. At worst, it's possible that running the fans at speed is at least partially obstructing the free flow of air. Although even in that "worst case" scenario you'd still be moving the amount of air the fans are rated for, which should still be more than enough to keep the car cool. It just might be less air flow than you would get through the radiator without the fans.

Basically it's just inefficient. Once the incoming air reaches the same volume as what the fan can move there's no reason to run the fan. One of the biggest advantages of using an electric fan is that you can turn it off when it isn't needed, so it's not constantly stealing power like a mechanical fan is.