Does the fan shroud do anything important or is it ok to remove it?

 

Of course it is important. Without it the radiator would not be be able to cool as well and inturn the coolant temp would be elevated which would make the engine temp higher which increases the chance of the coolant seals melting which means rebuild.

 

Keep it. Or get one if you don't have one.

 

Remove it while leaving it attached to your radiator. This way, the car will weigh less and you can drive it faster. Good for 45 Hp on a dyno.

You can also remove your clutch, differential, the windshield and your heater core. They are also useless under certain circumstances.

Good luck!

 

Awesome thanks for the awesome tip I love people who waste their time being a$$ h0les instead of just answering the question. I only asked is because when people run e-fans that dont have a huge shroud like the stock one or none at all.

im so glad you let me on to your secrets about gaining hp I would have never been able to reach 1000hp if i didnt take off my rad and shroud to go along with the 935 hp i got with all the stickers I have on my car !!!!!!!

 

remember, there are no stupid questions, just stupid people.

 

Even efans benefit from shrouding.
In fact, an efan mounted in the stock shroud would probably be the ideal setup.

A shroud allows the fan (either mechanical or electric) to pull air through the entire rad core.
The further the shroud spaces the fan from the core, the more the fan hub "dead space" is minimized.

While the close spacing of say, the Taurus efan, works, it'd work even better if it was further away.
This is rarely done, mostly due to convenience or looks.

 

Hey man, it's your thread. I was just holding up my end of your conversation. You gotta give us more to work with. If you want good answers, ask better questions- give us more detail. Don't make us play '20 questions'.

You didn't say you wanted to know about efans?



BTW, what kind of stickers you got?

 

Some where I have a fan shroud calculator in excel, but I cannot put my hands on it. It is used to determine the fan setback required to allow the shroud to equalize the flow across the face of the radiator.

Basically, the rule of thumb is that you need 1 square inch of free air space for every 2 square inches of radiator area covered by the shroud. So we can do the following to make sure that the fan pulls evenly across the face of the rad-

Calculate the area of the radiator in square inches. Subtract the area in square inches covered by the fan.

This gives you the total area in square inches covered by the shroud.

Calculate the circumference of the efan in inches.

Divide the total area covered by the shroud by the circumference of the fan.

Divide by 2.

The result is the distance from the face of the rad that the shroud should be setback.

So for my Griffin and my Mark VIII 18" fan:

19x18=342" sq. Rad area.

3.1416*(9*9)=254"sq. Fan area

342-254=88" sq Area covered by shroud.

3.1416*18=56.5" Circumference of Fan

88"/56.5"=1.56 Ratio of shroud area to fan circumference.

1.56/2= .778" Setback as the minumum.

So, we have the minimum distance the 18" efan must be set back is about 3/4" from the face of the my griffin radiator.

Since the shroud is actually 2" deep and the fan hub is slightly over 1", I am way above the design minimum, more than double. I have a high degree of confidence that the face velocity is uniform on my radiator.

Do the same exercise on your Taurus fan and you likely will find that Ford did a great job engineering that fan.


EDIT: Here it is

 

That's an interesting bit of info Jack, however I think it ignores two factors (probably for simplicity's sake) that could have a significant impact.

-In a static scenario (i.e., car at rest and all airflow generated by the fan) the fan hub is a dead spot where no air is being pulled through.
Within reason, the further the fan is spaced from the core, the less this is a factor.
Since our fans have fairly large hubs, this could be a worthwhile factor to deal with.

-In an active environment (car in motion), the fan is probably not even running and a close fitting, flat shroud (such as the Taurus part) is actually restricting airflow.
I've seen some cars (Volvos, for instance) that have flexible flaps on the shroud that open when pushed by incoming air, thus increasing flow.
Alternatively, a deeply shaped shroud like the stock part would do much the same thing.

For the most part, these are probably moot points.
My Taurus fan, with it's flat,shallow, non-vented shroud, has worked flawlessly- which is why I haven't tried any of the (theoretical) improvements mentioned above.
Next summer I might though, just to see what happens.
I figure that somehow logging the amount of time the fan runs under various conditions would be a good way of telling if an improvement had been achieved.

 

2 things here:

1.) The hub is wide by design. On an axial fan the air is primarily moved by the outer portions of the blade, very little is moved at the center. As static pressure rises, the center of the fan will actually experience reverse flow. The wide hub is a physical barrier to this phenomenon. Thus by intentional design, the hub is wide. Efficiency under higher static pressures is increased.

2.) If the hub is sufficiently spaced back from the face of the rad, there is no blockage. Use the principles in the fan calculator to determine if it is or is not spaced properly. The calculator is not setup for hub calculations, but the math is the same, just take it the next step. My bet would be that the hub as it comes from the factory is spaced optimally.

If it is not designed correctly, yes. Again, theory can be tested by doing the math. Fan Calculator to the rescue! If the spacing on the shroud does the job with the fan, then it provides sufficient relief for the highway.

In your experience, does this occur on your setup? Do you have high fan use on the highway?

These relief flaps are usually found on cars that have larger radiators and smaller fans, or on multi-speed and/or multi-fan arrangements. These are indeed to allow flow in fan-off conditions, primarily highway.

Your Taurus fan doesn't need any of those details because Ford did the design work upfront. That is the reason the Taurus fan is such a great part. Most people think the fan is some kind of high-amperage monster. No, it is just a completely functional design.

I don't think you will be able to measure significant differences, because the variables are too many. But keep us informed. Maybe do one of your project threads?

 

Although I agree that the Taurus fan is a "completely functional design", I can't help but wonder what it might look like absent the packaging constraints present in the original application.

Basically, they just didn't have a lot of space to work with, unlike the RX which has considerably more room to play with.
That said, it is all a pretty moot point...I have essentially NO fan use on the highway and, due to the activation triggers I've used (low speed at 190°, high at 210°), minimal use in all but the heaviest traffic.

If anything, when it comes to modifying my current install, I'd probably redo my trigger switch set up and go for two separate sensors instead of the integrated twin switch I now have.
This would allow for easier tweaking of the fan activation should I decide to explore in that direction.
Which I probably won't...
Hell, with the advent of winter weather, my fan hasn't come on at all for the past several weeks.

 

this is really good info! I'm going to school for Mechanical Engineering so I love when I read technical stuff like this. Anyways, I like the idea of flaps in the shroud that allow air to flow and decrease resistance at high speed, or the fan blades turning too. Imagine how much difference that would make at 150 mph, or even 200 mph. Aren't there some hoods that are basically designed with a scoop outlet for the engine bay air to vent? I guess ultimately the car still has the same square foot of frontal area, but it would definitely improve the air flow at the front and through the cooling system and all.

idk, but I know my turbo II is missing the engine bay underbody panel and I'm sure that affects the airflow and protection of my radiator and oil cooler. So I've been thinking about making a custom one, it'll be solid and sealed in front of the radiator so the air entering the bumper can't escape and have vents with a rear facing opening to allow air out of the engine bay once it's pass thru the radiator. What should I make it out of tho? I was planning to just go to Lowe's and see what I can find.

 

Forget Lowe's, find yourself a good plastic supply company and get a sheet of ABS plastic...3/16" thick should work well.
It's ridiculously easy to cut, drill and heat form, resistant to most of the common liquids it'd be exposed to, lightweight and not prone to cracking.
Plus, it's available in black, so no paint required.

That's what my ducting will be made of...when I get around to it.

 

http://www.rplastics.com/abssheet.html
this company has a .187" thick 24" X 48" sheet of abs for $45 before shipping. But I might just make this thing out of a couple layers of fiberglass, would it stand up to chemicals and impacts? maybe if I paint it with rubberized undercoating? idk yet.

Your right though abs sounds like a very ideal material for this use.

 

I'd prefer ABS over fiberglass because it's not as brittle but I suppose this depends a lot on the type of mat and resin you use.
ABS sheet would be considerably less mess to deal with as well.

I have access to a couple of local plastic shops, so shipping isn't an issue.
Last year I was quoted @$66 for a 4 x 8' sheet but the same place sells remnants/offcuts by the pound and I decided to wait for a suitable piece to show up in the "waste" bins.

This spring when the weather warms up, I'll probably just bite the bullet and buy a full sheet...

 

Lol OP the sarcasm really was an answer. Don't do it man.

On the stock fan without a shroud you could easily overheat at idle because there's nothing to keep the fan from puling air from the engine bay instead of the radiator. The car would be undrivable.

Most aftermarket efans come with a shroud going the full 3 inches from the radiator to the fan, insuring all the air is pulled only from the radiator. So the stock shroud isn't necessary with an efan. Though some offset would be nice since the fan only covers part of the radiator and air from the rest of the radiator has trouble changing direction so fast.