:hehe: I thought you said the change was in the 2008 MY. My 2005 certainly has viscous drag when I attempt to spin it by hand with the engine stopped. I haven't actually tried this, but as I understand it, the drag should be greater if the engine is hot. (I'll have to give it a try). In my engine, the fan ALWAYS turns, but, it is supposed to turn faster (closer to engine speed) with the engine hot. (I know you know this, I'm just adding it for anybody who may not understand how a viscous clutch works).

I doubt you could measure it with a fish scale though on a stopped engine. You'd need to catch the fan to a scale mounted on a rafter or something and measure the force on the stalled fan with the engine running. Then, you could calculate the torque/hp loss from this force and the distance you had the "hook" from the hub. It's not something I'd like to try, since it sounds a bit dangerous.

But, if there is NO resistance in the 2008+ line, then that is a whole different clutch! And, you should be able to compare the relative resistances in different MY trucks by feel.

- Jack

2006 or 2007, AFAIK. PCM-controlled fans have a harness with connector a 5 wires that sit between the water pump pulley and the fan hub.


If harder to turn when hot and no wiring, then that sound like your 2005 has thermo controlled clutch.

Right, not a good idea to do it that way.

Here is some more reading on fans:http://dygytalworld.ehost-services13...read.php?t=467

Lars

Of course I'd completely forgotten that thread, Lars. AgentOrange really improved HIS mileage with the e-fan, didn't he? Same truck as mine too.

Looks like, according to my Haynes manual, that your 2006 had the viscous clutch fan too. Didn't you put in e-fans Lars? I know you replaced the pulleys. How has all this effected your mileage?

I guess the next time I'm at the dealership, I should go try to move a fan by hand to compare the resistance in the newer setup with mine. There's no doubt at all that there's significant, CONSTANT drag on the engine with my fan, regardless of the need for cooling.

- Jack

about to add the e-fans. need to do anything? just up the idle speed?


for anyone that has them, what did you set the temps at? i live in seattle so its never super hot and never super cold

I don't think the ambient temperature is of concern to you. What does matter is the engine temperature. You'd like it to be in the 200 degree range, for best performance and fuel economy.

I don't have them, but I think I'd start cooling things off if I saw 210 degrees.

And of course, you do not want them on at all if the engine is cold.

- Jack

yeah i see that most people turn them on at 195 and 205 or so

i still havent got them yet, but i really shouldnt have to screw with them that much correct?

No efans yet.
Got .5 mpg better and more pep in stock.
Just a note on troyer's controller: Use a SPAL one instead.
Detailed instructions come with the kit.
Use a ir point and shoot temp gauge on upper radiator hose to determine on temp.

Lars

ok so i installed them today and got them running.

heres a couple questions

i set the fan to come on at about 195, should i set it higher? lower?

to set the second fan at 205 is it easiest to drive until i get to that temperature and then run and turn it on? i had it sitting running in the driveway for a good 15 min and never got above 196

How are you measuring the temps?

Using an ir gun or the gryphon. Set the gryphon on CHT pid it should be anywhere from 202-208 if still at stock or canned tunes. If you have custom tunes it will be 2-4 degrees higher. So set the second one at 210?
Take her for a short test run to confirm. Others have gone through the expense and mounted leds to see when theirs turn on.

This maybe simpler.
This is courtesy of f150online. They are using the ECT on the edge. Here's the link:
http://www.f150online.com/forums/v8-...ml#post3055325

Lars