Electric versus Flex Fan

[Jb427]

I always run 2 Spals, big as I can fit, with an on/off pressure switch in the water jacket.  Usually on at 180F, off at 170F, or somewhere close to that.  No shroud, to avoid blocking airflow through the radiator at high speeds.  Works great, even on my 1000 HP Drag Week car.  I've never had an electric fan failure.

Jay how do you find no shroud in traffic I am thinking of removing mine I have no problems in traffic but on long highway drives I am sure my shroud is killing the airflow even with large airflow flaps

[TJ]

I just don't think I am pulling much air, fan blades are ~1" back from the rad. face and it has to pull through radiator and condensor, and even the oil cooler for part of it and like I said shroud is a home brew not sealed well to the fan blades.

Where the fan sits in the shroud opening (about half in and half out) is more important than how close the fan is to the radiator.  In a car, you may not have the room for proper spacing of a belt driven fan within the shroud and kinda need an electric fan

Besides spinning the fan faster, pulley choice will spin the water pump faster which may or may not help your scenario. 

[TJ]

For my own curiosity, what is the coolant capacity on your thunderbird with the 445?

[fryedaddy]

i hope your not sucking the bottom hose shut on acceleration.i had that problem one time,every time i drove it,it got hot,when i slowed or stopped it got better.i revved it up with my hand on the carb and i saw the bottom hose suck flat when i revved it up.i put a spring in the bottom hose and it never happened again.

[GerryP]

...
Gerry, do you know how thick the Taurus fan setup is, between the rad and the electric motor?

Four and a half inches.  Here's a spec sheet from the manufacturer:  https://www.rockauto.com/en/moreinfo.php?pk=1407423&cc=1138766&pt=2181&jsn=8

[jayb]

I always run 2 Spals, big as I can fit, with an on/off pressure switch in the water jacket.  Usually on at 180F, off at 170F, or somewhere close to that.  No shroud, to avoid blocking airflow through the radiator at high speeds.  Works great, even on my 1000 HP Drag Week car.  I've never had an electric fan failure.

Jay how do you find no shroud in traffic I am thinking of removing mine I have no problems in traffic but on long highway drives I am sure my shroud is killing the airflow even with large airflow flaps

The Spal fans come with their own circular shrouds.  Never a problem in traffic, even on a hot day.  In most of my cars I end up with one puller and one pusher.  Two pullers is better, if you can fit them.

[Thumperbird]

This is great info., thank you everyone, I think I know which way to go now if I want to make the change, piece of mind is worth it I think.
The FE Thunderbird has ~5 gallon cooling capacity.

Sorry to bother but one last question, Jay you mention locating the switching sending unit in the "water jacket" do you mean some where on the side of the block or is the typical location on the intake manifold behind the thermostat ok? (Edelbrock air gap)  I don't want to loose my gauge sensor so will have to figure out how to get both in the flow.

Thank you.

[GerryP]

...or is the typical location on the intake manifold behind the thermostat ok? (Edelbrock air gap)  I don't want to loose my gauge sensor so will have to figure out how to get both in the flow.

Thank you.

The most accurate point to measure your coolant temperature is the furthest point forward as the coolant is leaving the engine.  If you can, get a later thermostat housing that has the boss for a coolant probe.  If you take your temperature reference in the block, you might be getting the coolant being pumped out of the radiator, which is going to be about 20 degrees cooler than the engine discharge coolant temperature.  The temperature deltas in the cooling system are fairly narrow between what goes into the radiator, what goes out of the radiator, what goes into the engine, and what comes out of the engine.

EDIT:  Here's a link to a thermostat housing -1970 Mustang CJ- with a sensor boss:  https://www.rockauto.com/en/moreinfo.php?pk=819191&cc=1440951&pt=10337&jsn=467

[jayb]

I usually put mine in the intake, as close to the thermostat as there is a pipe fitting.  You can use a Tee fitting, sitting flat, to accomodate your original temp sender plus the sensor for the electric fan.  But Gerry's way is better, if you have a thermostat housing with a pipe fitting in it. Only downside there is if the thermostat sticks shut, you won't see an accurate temp at the sensor.  Of course, with no flow through the radiator, what good would the fans do LOL!

[TurboChris]

Should check this out as well. Soft start and can use for AC. My brother runs one and loves it. Only runs as much fan as you need.

https://www.autocoolguy.com/home

Don't know if the product is good - - but spell check could help out a lot on that site

He's a one man business. The product is good tho. If you REALLY want the latest greatest these are the guys I'm looking at for my Fairlane.

Their fans put out huge cfm (they have videos showing testing) and their controller is about the nicest I've seen yet.

https://deltapag.com/

[Tunnelwedge]

I use a probe and switch on the rad to control the fans.
You can move the probe around.
Most of the time I do not need the fans on.
Only in traffic at slow speed. Which I try to avoid.

[Barry_R]

I run my pair with one switched along with the electric water pump and the other on a temperature switch in the thermostat location.  Since going to the Spal stuff many years ago after seeing them used by the street rod community I have only had the second fan come on a few times.

[lalessi]

I have a 462 FE , 501HP in a '57 Ford (small engine bay). I started with a "16" " Derale puller fan/ shroud, it even overheated on the interstate. (BTW I have a Griffin radiator). Next attempt was (2) 12" Spal puller fans on a custom shroud. They were marginal at best and did not keep the temp down after the AC was installed. I finally got the temp to stay under 190 using a Derale 7 blade 19" clutch fan/custom shroud (Hayden custom shallow clutch). The temp would start to creep up with the AC on so I installed a 16" Spal pusher fan that comes on with the AC on. My car would barely run over 205 with the carb I was using (tried everything to fix that too) so I switched to EFI. Now I can drive the car on a 100 degree, 50% relative humidity day in south Louisiana in stop and go traffic. A bigger radiator was not an option w/o MAJOR surgery. very little room between the engine and the radiator to boot.

Can offer more details/pics if needed and I still have the fans if anyone is interested.


Lynn

[Chrisss31]

He's a one man business. The product is good tho. If you REALLY want the latest greatest these are the guys I'm looking at for my Fairlane.

Their fans put out huge cfm (they have videos showing testing) and their controller is about the nicest I've seen yet.

https://deltapag.com/

That looks pretty slick.  I'd like to see the actual CFM reading through a radiator though.

[pbf777]

I started with a .......................... . Next attempt was ...................... I finally got the temp to stay under 190 using a Derale 7 blade 19" clutch fan/custom shroud (Hayden custom shallow clutch). The temp would start to creep up with the AC on so I installed a 16" Spal pusher fan that comes on with the AC on.

     We have been trough this time and again over the decades at our shop here in Florida (it does get hot & humid!  ) and this is pretty much the normal process that many of our customers have followed (though also including a flex-fan vs. just the clutch-type) and the final conclusion established in instances where the cooling systems' capabilities are truly being tested.   

     These repeated experiences are what led to my previous statement of:

      In these older type chassis, for one's typical "street car" use applications, and with consideration of what is typically marketed as,  I consider electric fans as best utilized as being "supplemental", this to the existence of the best execution of the mechanical fan first.       

     Scott.