I hope I don't start a war with this, but I need some opinions. I've been running dual Troyer fans for about 4 years and rarely if ever did the second fan come on except when the a/c is on. However, I don't care for the way my a/c cools because of the gap between the radiator and the a/c condensor. There seems to be a huge loss of the pulled air. So here goes: Would one fan mounted on an aluminum shroud be sufficent to take care of the cooling needs of my 5.4 ? It appears that the lack of a shroud is where I'm losing the air to cool the a/c condensor. OK. let em fly.

 

A lot of people run the single 18" Mark VIII fan. Apparently it flows better than most dual fans, somewhere around 4000-4200 cfm If I remember right (could be exaggerated). I personally would one build it into the factory shroud, to help keep the direction of the air pulled. Someone had a write up around here with it incorporated into the factory shroud.


How many miles on your truck? Maybe due to old refrigerant or low refrigerant

 

I don't think it's due to old refrigerant, refrigerant doesn't wear out. It's due to the truck's residing in Az. The Ford 18" is indeed a good choice and it can be off a Crown Vic. even. That's what all the Police CV's have used for quite a few years. They started using a multi plastic engine fan AND and 18" electric and found out it was pointless to have the engine fan because the 18" electric did the job under severe conditions with no problem at all. It DOES draw quite a lot of amps though. It IS important, as Toyz said, to have it shrouded so that ALL the air is sucked through the radiator (and condensor). If you want the A/C to work well in a hot climate, especially in traffic, put a ball valve in the heater line so that you can shut off the water flow in warm weather and put a "mister" in front of the condensor. If it doesn't cool well then , it NEVER will. This is assuming you have adaquate electric fan cooling.
One thing about the CV's that helps I think is that when they went to only electric fan, they SLANTED the fan (shroud) somewhat downwards so that it didn't blow the hot radiator air directly across the engine.

 

I need to clarify a couple of things. First, The a/c works great with the stock clutch fan and shroud and the single fan I was refering to is one of the Troyers.

 

Not a 5.4, but here's my experience w/ a single e-fan on my 4.2 ...

I have an aftermarket temp gauge installed in the heater input hose, so I'm able to closely monitor the coolant temp.

I installed a Lincoln Mark VIII fan into the factory fan shroud. The fan pulls air only throught the radiator, and through the full width and height of the radiator, as well.

My fan is controlled by a DCControls FK50P controller (soft start, variable speed), set for a 192 degree thermostat. I have also installed DCControl's fan speed indicator, which gives me some idea of how fast the fan is spinning.

The controller turns the fan on 50% when the AC compressor is on. I have this feature wired to a switch, so I can disable it when I'm running the AC at highway speeds (no need for a fan when 65 mph air is being rammed through the radiators).

The only time the fan comes on is when I'm travelling slow (less than 35 +/- mph),when it will turn at somewhere less than 50% speed for less than a minute every couple of minutes. When I recently took my truck in for a smog check (where they idle the vehicle for approx 20 min), I could hear the fan turning on, again for less than a minute every few minutes. I have yet to work the truck hard w/ the e-fan installed, though.

At slow speeds, the AC (w/ the fan on at 50%) works far better than it did w/ the factory fan. At highway speeds (w/ the fan off), the AC seems about the same.

While I'm sure a Mark VIII fan is adequate for a 5.4 in most situations, I have no idea if it is adequate for a 5.4 in the most extreme conditions. It is designed to cool a V8, but I can imagine situations where a truck could ask far more of a cooling system than a car (100 + degree air temps, fully loaded, towing up a steep grade at slow speeds w/ the AC on). My guess is that one of your Troyer fans pulls significantly less air than the Mark VIII fan, but together they probably pull a little more than the Mark VIII fan.

If I was to do this mod again, I would look closely at the factory 2010+ F-150 e-fans, mainly from a reliability point of view. I'm a little concerned about the long term reliability of the 18 year old Mark VIII fan I have in there now.

Were I in your situation, I'd probably fabricate some kind of shroud, incorporating both of your Troyer fans. I used aluminium highway sign panel to extend the Mark VIII shroud to fit my factory shroud ...


Pic of test fitting the shroud extensions ...

 

Hmmmmmm!

 

Helps when you work for Caltrans, eh?

 

Doesn't hurt ....