The spinning blades create more drag, this is a fluid dynamics fact. They also create turbulence, which
can slow the incoming air because of how it disrupts it. That last bit is specific to the particular radiator/fan/shroud arrangement, the speed of the blades, the volume and speed of incoming air vs outgoing etc... Which is why I say "at best" and "at worst". Unless you put it in a wind tunnel you can't know 100% for sure.
But given the efficiency to which modern cars are designed, you had better believe that if it was more efficient to run the fans all the time that's how modern cars would work. Especially since it would be a lot easier to just constantly run the fans than it is to program fan control parameters into the ECU.
Yessir. And the fans on the contour motors do not windmill when the are not running.
@512Stroker, you can disagree if you want, but the simple fact is that if you choose an electric fan that moves enough air to cool your engine, supply that fan with enough power to run as it's designed and control the run time of the fan accurately the electric fan will work better and steal less horsepower from your engine. That's the engineering that makes it work on new cars, it's no different for a retro-fit. If you pay attention and build an appropriate system for an aftermarket upgrade on one of these cars it will work just as well. It's no different than picking a carburetor and building a fuel system to supply a higher horsepower engine. If you run an undersized carb and starve it for fuel, you get a poor result. You wouldn't say all carburetors are bad in that case, you'd just get a bigger one and supply it better. Same deal with an electric fan. People fail with their electric fan retro-fits because they either don't pick fans that move enough air, they don't wire them appropriately, or they don't control them accurately. Or some combination of all of those factors.
