[RTT]

When I went from my tired 305 to my mild 355 I installed a new Murray radiator and a high Perf 6 blade 18" fan advertised to move much more air than a stock fan. It was belt driven continuous. Now that hot weather is here (105-110 degrees), she has been running a little warm with the AC on (205-215).
This last weekend, I put the stock 5 blade 16" fan back on with a Hayden severe duty fan clutch. Guess what? She is running about 7 degrees cooler! Apparently that big fan put a big drag on the motor that out weighed any benefit. I guess the factory guys know a few things.
I am contemplating putting an electric fan on the front of the rad to push air to assist the clutch fan here in the desert west.
RTT:nanawrench:

 

[HKDUP87]

When I went from my tired 305 to my mild 355 I installed a new Murray radiator and a high Perf 6 blade 18" fan advertised to move much more air than a stock fan. It was belt driven continuous. Now that hot weather is here (105-110 degrees), she has been running a little warm with the AC on (205-215).
This last weekend, I put the stock 5 blade 16" fan back on with a Hayden severe duty fan clutch. Guess what? She is running about 7 degrees cooler! Apparently that big fan put a big drag on the motor that out weighed any benefit. I guess the factory guys know a few things.
I am contemplating putting an electric fan on the front of the rad to push air to assist the clutch fan here in the desert west.
RTT:nanawrench:

Mine is stock and I'm running 205 with the air on.

 

[darbysan]

An electric fan is a good upgrade, especially for desert living. It gives you max airflow in stop and go traffic, with the AC on. A pusher is not a bad idea, but remember that it will block some of the airflow, so it's almost a trade-off ( except for the stop and go benefit.

Replacing the stock fan with a puller electric is a very good alternative. I have a Mark VIII fan on mine, and it pulls a lot of air. It is a single fan, though, and as I found out last week it can go out. I'm leaning towards a dual fan setup, so that if one motor or fuse goes out, you can still limp home. Dodge Intrepid fans are a common choice. A second choice I am looking at is the Mercury Mystique 2-fan setup ( only on certain models of Mystique and Cougars). They pull more air, but are harder to find.

Bottom line is that the electric will not cool better than the stock fan setup, except at slow speeds or in traffic. However, they can be set to come on only when you need them, so no extra drag at freeway speeds or when the OAT is lower.

 

[69/84]

The Factory fan was "Matched" to the Fan Shroud...
The new fan with a deeper pitch was likely Cavtitating (Spinning in its own Void) in the stock shroud and flowing less air.

If the New larger fan was matched with a larger shroud, it would likely flow a lot more air at low speeds...

If it is a Flex Fan then it will drop out early and you may need to under drive the fan pulley to keep it in action for a longer period of time...Nothing is as simple as it seems...

I am running dual electric Spal fans...Love them!

 

[ALAsh]

The Factory fan was "Matched" to the Fan Shroud...
The new fan with a deeper pitch was likely Cavtitating (Spinning in its own Void) in the stock shroud and flowing less air.

If the New larger fan was matched with a larger shroud, it would likely flow a lot more air at low speeds...

If it is a Flex Fan then it will drop out early and you may need to under drive the fan pulley to keep it in action for a longer period of time...Nothing is as simple as it seems...

I am running dual electric Spal fans...Love them!

X2 on the Dual Spal fans...
Computer controlled.... Set em and forget em...

The cool thing (no pun intended) is the ability to set the on and off temp at which the electric fans operate. And my Pro-Comp temp gauge indicates they are spot on relative to the settings I programed.

A bit pricey but then, so again, is replacing/rebuilding a motor !!!

Arnie in Iowa