Electric fan with the factory shroud
03-07-13, 11:11 AM
#26
i actually think part of the reason for my success changing fans was the aftermarket shroud covered the ENTIRE radiator and the taurus fan does not, I think at highway speeds the fact that some air can pass through freely is vital to its success.
I had wanted to try the other shroud with some flaps or even holes, but I sold the set up instead and advised the new owner to consider flaps if he was intending on a FMIC and AC
once you take AC and a FMIC off the table you can probably run anything and it will work well
I had wanted to try the other shroud with some flaps or even holes, but I sold the set up instead and advised the new owner to consider flaps if he was intending on a FMIC and AC
once you take AC and a FMIC off the table you can probably run anything and it will work well
03-07-13, 11:59 AM
#29
Actually, just the opposite.
Spacing the fan off the core increases its efficiency and mitigates the "dead zone" below the fan hub.
I've looked into doing this exact thing before but rejected for two reasons....
About the upper third of the fan is effectively blocked by the shape of the shroud itself and spacing between the fan structure and the waterpump snout is tight.
Does your modified shroud/fan fit?
Spacing the fan off the core increases its efficiency and mitigates the "dead zone" below the fan hub.
I've looked into doing this exact thing before but rejected for two reasons....
About the upper third of the fan is effectively blocked by the shape of the shroud itself and spacing between the fan structure and the waterpump snout is tight.
Does your modified shroud/fan fit?
I will try and get a photo of the fan assembly installed this evening to show the clearance from the electric motor housing to the water pump pulley.
Last edited by DeaconBlue; 03-07-13 at 12:12 PM.
03-07-13, 12:03 PM
#30
Yes, I was surprised on how much easier it would be to work on the front of the engine with the factory shroud not blocking access to most everything. Well now that the factory clutch fan is out of the way, at least it will be easier to remove the shroud if necessary.
03-07-13, 12:23 PM
#32
Since I have not yet seen an electric fan that was mounted in the same position as the factory clutch fan and using the factory shroud, maybe that could be part of the secret? This fan is rated for a much heavier and higher horse power application so it should be fine for my n/a 13B. I will not know for sure until the heat of summer with the a/c running and stuck in traffic or out at a track day event. If for whatever reason I find that I do need more air flow capability, there are always the 2500 CFM 16" fans to choose from.
03-07-13, 12:28 PM
#33
yes, the n/a fan is oversize for the application.
for CFM, i haven't found any documentation. only references i have are comparisons of e-fans running hotter than the stocker even on large core radiators. e-fans also generally have 1 or 2 speeds, versus the thermofan which accelerates with engine speed to keep up with the requirements of the engine.
there are a few exceptions, the Flex-a-lite black magic seems to do about as well as the stocker. the taurus e-fan being a little superior on high speed. most others have ducting problems or the CFM lacks the compared to the documentation provided from the manufacturer. the black magic fans having burnt up MANY control box connectors internally due to poor connector quality.
so with all that i still rely heavily on the mechanical fans due to their obvious superiority on most cars/setups.
for comparison sake i have used the black magic on a 500whp FC and we use the massive taurus fan on a 13BRE cosmo FC setup for about 700whp. so far they seem to do ok, with some hurdles thrown in for good measure(numerous black magic failures, in some cases i initially chopped the wiring directly to the fan motor and installed a manual switch in case of control relay failure).
the issue with most is ducting, setting the fan directly on the radiator either doesn't cover the whole core or the airflow pulled across the core is lessened due to turbulence. i like the original post using the stock shroud but as clokker mentioned, it has other problems with fitment.
for CFM, i haven't found any documentation. only references i have are comparisons of e-fans running hotter than the stocker even on large core radiators. e-fans also generally have 1 or 2 speeds, versus the thermofan which accelerates with engine speed to keep up with the requirements of the engine.
there are a few exceptions, the Flex-a-lite black magic seems to do about as well as the stocker. the taurus e-fan being a little superior on high speed. most others have ducting problems or the CFM lacks the compared to the documentation provided from the manufacturer. the black magic fans having burnt up MANY control box connectors internally due to poor connector quality.
so with all that i still rely heavily on the mechanical fans due to their obvious superiority on most cars/setups.
for comparison sake i have used the black magic on a 500whp FC and we use the massive taurus fan on a 13BRE cosmo FC setup for about 700whp. so far they seem to do ok, with some hurdles thrown in for good measure(numerous black magic failures, in some cases i initially chopped the wiring directly to the fan motor and installed a manual switch in case of control relay failure).
the issue with most is ducting, setting the fan directly on the radiator either doesn't cover the whole core or the airflow pulled across the core is lessened due to turbulence. i like the original post using the stock shroud but as clokker mentioned, it has other problems with fitment.
Last edited by RotaryEvolution; 03-07-13 at 12:40 PM.
03-07-13, 01:06 PM
#34
One of the key things to remember about cooling fans is that they are needed the most at low vehicle speeds, typically when the engine is also spinning slowly. So the clutch fan has to be sized to move enough air during a heat soak period with the vehicle stopped and the engine at idle speed meaning the fan is at its lowest speed. You do not typically need any fan with the engine at speed, because the vehicle is most likely moving forward and air is being rammed through the radiator due to the high pressure at the front opening and lower pressure inside the engine compartment and under the vehicle. That is why the stock fan has a clutch - it is supposed to be freewheeling at speeds higher than say about 35-40 MPH. Of course it really doesn't 100% free wheel, due to is design it simply can't, hence the point about robbing power from the engine.
The beauty of an electric fan is that is is turning at the rated RPM and CFM flow no matter what the engine or vehicle speed. So it will be providing maximum air flow when you really need it the most.
I agree that most of the problems with generic or salvage yard electric fan swaps involve the shrouding or the lack there of. I just thought that reusing the factory shrouding would be a great way of proving this, plus it maybe one of those "sort of neat" mods that has never been done/tried before - that and it didn't cost me personally any money since I already had the fan on the shelf in the garage
No it may not be for everyone since it still limits access to the front of the engine - but it still maybe yet another choice for those looking to install an electric fan.
As always YMMV.
The beauty of an electric fan is that is is turning at the rated RPM and CFM flow no matter what the engine or vehicle speed. So it will be providing maximum air flow when you really need it the most.
I agree that most of the problems with generic or salvage yard electric fan swaps involve the shrouding or the lack there of. I just thought that reusing the factory shrouding would be a great way of proving this, plus it maybe one of those "sort of neat" mods that has never been done/tried before - that and it didn't cost me personally any money since I already had the fan on the shelf in the garage
No it may not be for everyone since it still limits access to the front of the engine - but it still maybe yet another choice for those looking to install an electric fan.
As always YMMV.
03-07-13, 01:11 PM
#35
true about at speed necessity, i just find that the thermofan doesn't draw all that much power when the clutch works as designed and pulls a fair amount of air with the shroud versus many other fans with poor circular/square on the radiator ducting without covering the whole core and while sitting so close to it.
the biggest drawback is getting the shroud on and off. with the fan located in the opening, the easiest and probably only method of getting to the front of the engine is by removing the radiator completely(since the shroud can no longer be walked on and off the radiator).
the biggest drawback is getting the shroud on and off. with the fan located in the opening, the easiest and probably only method of getting to the front of the engine is by removing the radiator completely(since the shroud can no longer be walked on and off the radiator).
03-07-13, 02:08 PM
#37
A watercooled PC does not have to contend with airflow directed at/through it, it lives in a mostly static environment.
The auto fan must compromise the efficiency of the blade design to allow for better flow when the fan is inactive (a state the PC fan never encounters)...the better the pull ability, the more of a barrier to outside airflow the fan becomes.
Hence the use of diverter flaps in some shroud designs.
The auto fan must compromise the efficiency of the blade design to allow for better flow when the fan is inactive (a state the PC fan never encounters)...the better the pull ability, the more of a barrier to outside airflow the fan becomes.
Hence the use of diverter flaps in some shroud designs.
The link I provided was not at all related to automotive cooling, it was purely to show that scientific minded people have setup private testing for parts much cheaper than engines. I'm surprised with so many min/max people in auto performance hobby/profession that someone hasn't done similar work at archiving.
03-07-13, 06:11 PM
#40
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03-07-13, 10:25 PM
#44
...the biggest drawback is getting the shroud on and off. with the fan located in the opening, the easiest and probably only method of getting to the front of the engine is by removing the radiator completely(since the shroud can no longer be walked on and off the radiator).
03-07-13, 10:54 PM
#45
So I turned the fan assembly around inside the shroud. Luckily the epoxy had not yet cured completely allowing me to flip the "L" brackets and then re-secured the fan in the same manner as before. I reversed the fan blade and used some foam to seal up the gap between the fan and shroud.
Plenty of clearance now. One extra benefit with the fan flipped is that the fan blades are now further from the contour in the upper portion of the shroud.
03-08-13, 07:05 AM
#47
My $0.02
The factory CFM rating on efans are mostly contrived. UNLESS they specify a tested pressure, ie xxxx CFM at 0.2" wc , the rating is a free air rating. Free air rating is meaningless and the manufacturers/marketers know it.
Additionally, some of even less honest free air ratings will include 'entrained air' movement.
What is entrained air? Entrained air is the air that comes along for the ride alongside the induced air. Induced air is the air actually moved by the fan. Easier to show than to describe.
Entrained air is not a factor in moving air across a heat exchanger.
Even less meaningful is the oft repeated 4000 cfm Taurus fan rating. One winter day, I searched that claim to the very end of the archived Internets. A guy used a Taurus fan to fill a 30 gallon trash bag, timed it with a stopwatch. He then did the math to calculate that the fan moved 4000 CFM of air. Now that number has been repeated so often that it is considered fact.
I had access to a wind tunnel at an aerospace company where my brother worked. We had plans to acquire test data on Taurus and Lincoln Mark VIII. Too bad he got crosswise with his boss and got fired. That was really inconvenient for me. Engineers, sheesh.
Does anyone remember when we used to talk about the 50 amp current draw of Taurus, until I did an actual test?
Regarding the OP project fan in the oem shroud. Great Idea! This should be the most effective way of mounting an Efan. I did this several years ago for a couple of Porsche 928 guys with a Lincoln Mark VIII fan as an oem replacement. They were struggling with the 30 year old mechanical fan clutches and huge replacement costs. The prototype worked splendidly, but ultimately they rejected the part since is was not gold-plated, did not come from Germany nor was it expensive enough.
Because there cannot be an electric fan thread with out my blabbering on about something...
Additionally, some of even less honest free air ratings will include 'entrained air' movement.
What is entrained air? Entrained air is the air that comes along for the ride alongside the induced air. Induced air is the air actually moved by the fan. Easier to show than to describe.
Entrained air is not a factor in moving air across a heat exchanger.
Even less meaningful is the oft repeated 4000 cfm Taurus fan rating. One winter day, I searched that claim to the very end of the archived Internets. A guy used a Taurus fan to fill a 30 gallon trash bag, timed it with a stopwatch. He then did the math to calculate that the fan moved 4000 CFM of air. Now that number has been repeated so often that it is considered fact.
I had access to a wind tunnel at an aerospace company where my brother worked. We had plans to acquire test data on Taurus and Lincoln Mark VIII. Too bad he got crosswise with his boss and got fired. That was really inconvenient for me. Engineers, sheesh.
Does anyone remember when we used to talk about the 50 amp current draw of Taurus, until I did an actual test?
Regarding the OP project fan in the oem shroud. Great Idea! This should be the most effective way of mounting an Efan. I did this several years ago for a couple of Porsche 928 guys with a Lincoln Mark VIII fan as an oem replacement. They were struggling with the 30 year old mechanical fan clutches and huge replacement costs. The prototype worked splendidly, but ultimately they rejected the part since is was not gold-plated, did not come from Germany nor was it expensive enough.
Because there cannot be an electric fan thread with out my blabbering on about something...
03-08-13, 07:29 AM
#48
I had a Taurus SHO 3.0L MTX with the factory electric fan for many years. I had to replace the wiring and connector to the electric fan and tried to use Packard Weather Pack terminals/connectors. Unfortunately they are only rated to a 16 Amps draw. When the connector melted - I also tested the Amp draw and had to change the terminal and connectors to a more robust design to handle the load.
Personally, I highly doubt that the Taurus fan moves much more than 3000 CFM. The shroud also leaves several inches on the passenger side of the Taurus radiator uncovered due to the stock location of the MTX overflow bottle. In fact the Taurus 3.8L Police/Taxi package as well as the 3.2L SHO automatic uses a twin fan shroud setup that moves some serious air and covers the whole radiator and has a differently located over flow bottle. The twin fan setup would not fit in the Taurus SHO 3.0L MTX because the engine sits 1.5" further forward and the exhaust manifold as well as the a/c plumbing were in the way of the second fan motor.
Personally, I highly doubt that the Taurus fan moves much more than 3000 CFM. The shroud also leaves several inches on the passenger side of the Taurus radiator uncovered due to the stock location of the MTX overflow bottle. In fact the Taurus 3.8L Police/Taxi package as well as the 3.2L SHO automatic uses a twin fan shroud setup that moves some serious air and covers the whole radiator and has a differently located over flow bottle. The twin fan setup would not fit in the Taurus SHO 3.0L MTX because the engine sits 1.5" further forward and the exhaust manifold as well as the a/c plumbing were in the way of the second fan motor.
Last edited by DeaconBlue; 03-08-13 at 07:32 AM.
03-08-13, 09:46 AM
#49
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