My thread

 

I don't think you can draw that conclusion from the changes that RAM has made. The clutch-fan system works just fine. Keeps the truck running cool under most conditions. E-fans allow you to free up some horsepower that was used to drive the fan, but if you have an E-fan, the power gets used up making electricity if the fan is on. There is no free ride when it comes to energy.

Just cruising around on a cool day, an E-fan will be a be a better use of energy. The alternator is making a low amount of electricity, charging the battery, using very little of the horsepower produced. Fan comes on when the water gets too hot, uses the stored energy in the battery, the cycle continues. If the truck is under a lot of load on a hot day, like towing a big trailer in stop-and-go traffic, it is probably a bad idea. The fan runs more often, so the alternator is under more load uses more horsepower. Converting the mechanical energy to electric energy and back to mechanical energy is less efficient than just spinning a mechanical fan.

There are losses involved in just having the clutch spinning without moving anything, but not too much, as far as I can tell. E-Fans probably help with the EPA mileage estimates, however.

 

i did the hhr fan/derale controller a while back & havent seen any measurable mpg benefits.

the motor does seem to wind up a little smoother,but even after careful adjustments to the "turn on temp" that temp gauge climbing a little higher sometimes when towing in hot weather has me seriously considering going back to the stock fan.

 

Installing a well-thought-out e-fan is (in my opinion) one of the easiest and cheapest ways of getting some guaranteed additional horsepower. I normally go for an "over kill" on the air volume, even though this usually means some current hungry fan motors, but the selection is usually pretty good from a lot of salvage yards - I recommend the Ford Taurus or Mark VIII fans and would also get the 2 speed if I wasn't sure of what type of controller I was going to install. If I was going to use a relay based controller, I'd definitely go with the 2 speed, but if I was going to use a PWM type controller, I'd probably get a single speed or whatever the yard had that was cheapest. Using one of these high volume fans from a salvage yard along with the pricey Painless PWM controller is still just as cheap or cheaper than getting a lower volume new aftermarket fan and a less pricey controller (the high volume fan is going to look after the engine on the hot days when you're towing or otherwise working the truck hard). If you're handy with electronics (or know someone who is), it's possible to build your own PWM controller - if you can program a micro-processor, you can make it pretty fancy, but otherwise, a good reliable analog unit with auto switching and speed variance based on temperature can be put together for a very reasonable cost.