dual electric fan mounting question ?

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j par

j par

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I got some dual electric fans from a member and I will have to mount one high left and one low right. they're just a little too big to put exactly side by side. I'm wondering if I should just use enough material to mount them behind the radiator? or should I put a big sheet aluminum behind the radiator and just cut two holes out for the fans? Thank you . .....
 
j par said:
I got some dual electric fans from a member and I will have to mount one high left and one low right. they're just a little too big to put exactly side by side. I'm wondering if I should just use enough material to mount them behind the radiator? or should I put a big sheet aluminum behind the radiator and just cut two holes out for the fans? Thank you . .....
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Something you might already know but worth mentioning. If you decide to use a sheet of aluminum and cut two holes, I would suggest boxing it in so the sheet is 1/2" to an 1" away from the rad but sealed off as best as you can. This will allow air to be pulled through the entire rad. If the sheet is lying flat on the backside of rad with holes cut then you are only going to pull air through those holes.
Whether or not you need the aluminum I guess depends on how much of a cooling problem you've had. Could try without and see how it goes.
I'm running two electrics, set up as pushers in front of the rad. They have their own shrouds with rubber seals and cover the entire surface. The rad is a 26" 4 core champion, never overheats on the hottest of days, even when stuck in traffic.
 
I can actually put the fans side by side. If i use the shroud mounts it will give only 1/4 inch between the rad and the aluminium cover that I'll mount the fans to, witch will mount with about a1/4 inch spacing. Also the aluminium sheet is about 1/8 inch thick (like stop sign material). I'm wondering if the 1/4 inch between the rad and the aluminium sheet will be enough ?
 
Rodzilla said:
Something you might already know but worth mentioning. If you decide to use a sheet of aluminum and cut two holes, I would suggest boxing it in so the sheet is 1/2" to an 1" away from the rad but sealed off as best as you can. This will allow air to be pulled through the entire rad. If the sheet is lying flat on the backside of rad with holes cut then you are only going to pull air through those holes.
Whether or not you need the aluminum I guess depends on how much of a cooling problem you've had. Could try without and see how it goes.
I'm running two electrics, set up as pushers in front of the rad. They have their own shrouds with rubber seals and cover the entire surface. The rad is a 26" 4 core champion, never overheats on the hottest of days, even when stuck in traffic.
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thank you for your help! I've never had a cooling problem with all the original stuff but that again was with a 318. Now I am putting in new stroker motor in it and going with electric fans and such. So I really don't know what to expect, but I am already trying to think ahead of the best cooling I can manage.
 
box it and run 2 holes. itll pull across100% of the radiator, not just 2 fan circles. try and get largest standoff as possible.
 
pishta said:
box it and run 2 holes. itll pull across100% of the radiator, not just 2 fan circles. try and get largest standoff as possible.
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the standoff is a bit of a concern as I don't have the motor back yet and not sure how much room I have.
 
I am in a similar situation that I want to get it all done before I drop in a 440. I decided just to wait and when the engine is in to test fit everything.
 
Box it in for sure, 1/4" won't be enough separation I think. Even an inch would be very good, I think most aluminum premade fan shrouds are about that high off the rad or close. The one I bought from champion is, but I couldn't use it with the fans I purchased.
 
1st, I would not recommend just putting a wall of metal for a shroud. You need to slope/swoop it like a nozzle/funnel. You need to give the air somewhere to go, not hit a wall....

another thing to consider is how much overlap the fan and shroud have. This a parameter that auto makers pay close attention. this is how much of the depth of the fan is overlapped by the fan shroud. This helps the fan pull the air through the radiator and shroud. You don't want the air going AROUND the shroud, but THROUGH it.... Start with half of the fan depth overlapped 50% (half in, half out) by the shroud and adjust to +/- 20%.

Now that it is going through the shroud, you need to keep it going, not hit a wall. This is why you blend the shroud fore/aft, so it directs the air to go through the path of the fan.

Otherwise you are not using the full capabilities of your fan.

Many auto makers put seals between the radiator and shroud to prevent any air "leakage" around the shroud.

Some of this may not apply to your electric fan appliction, but I wanted to show you the thought process to designing a fan shroud.
 
krazykuda said:
1st, I would not recommend just putting a wall of metal for a shroud. You need to slope/swoop it like a nozzle/funnel. You need to give the air somewhere to go, not hit a wall....

another thing to consider is how much overlap the fan and shroud have. This a parameter that auto makers pay close attention. this is how much of the depth of the fan is overlapped by the fan shroud. This helps the fan pull the air through the radiator and shroud. You don't want the air going AROUND the shroud, but THROUGH it.... Start with half of the fan depth overlapped 50% (half in, half out) by the shroud and adjust to +/- 20%.

Now that it is going through the shroud, you need to keep it going, not hit a wall. This is why you blend the shroud fore/aft, so it directs the air to go through the path of the fan.

Otherwise you are not using the full capabilities of your fan.

Many auto makers put seals between the radiator and shroud to prevent any air "leakage" around the shroud.

Some of this may not apply to your electric fan appliction, but I wanted to show you the thought process to designing a fan shroud.
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thank you for your input on that!
here's what I got so far. You can tell me what you think? I haven't cut the holes for the fans yet nor made little brackets to hold it to the rad. I'm thinking I may be able to caulk around the outer edges with black RTV or something easley razor bladed out if I don't like it.View attachment 20150210_174326.jpg

View attachment 20150210_172858.jpg

View attachment 20150210_172823.jpg

View attachment 20150210_172844.jpg
 
Any idea what cfm those fans pull? If you could get some rubber pinch seal for the contact area of the aluminum to the rad and the fan shrouds to the aluminum to help seal it up then it should probably work ok. Providing those fans can move a decent volume of air.
 
Rodzilla said:
Any idea what cfm those fans pull? If you could get some rubber pinch seal for the contact area of the aluminum to the rad and the fan shrouds to the aluminum to help seal it up then it should probably work ok. Providing those fans can move a decent volume of air.
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I was told the fans came on a 440 motorhome and cold it well but again that could have been a good radiator also. no idea on the actual CFM
 
j par said:
thank you for your input on that!
here's what I got so far. You can tell me what you think? I haven't cut the holes for the fans yet nor made little brackets to hold it to the rad. I'm thinking I may be able to caulk around the outer edges with black RTV or something easley razor bladed out if I don't like it.View attachment 1714792332

View attachment 1714792333

View attachment 1714792334

View attachment 1714792335
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That's a good start, but you need to add some sweep to the back wall, so it directs the air into the fans like a funnel. Think of it as mounting each fan in a funnel at the small end and the large end goes toward the radiator.
 
You are only two dimensional on that shroud, you need to add depth in the third dimension or z-axis.

Here's a sketch to show what I'm talking about. You have to swoop the back face of the shroud like a funnel going into the fans. You want a slope, not a flat brick wall for the air to run into...

View attachment Fan Shroud A01 B2.jpg
 
I do agree with Krazy, to optimize airflow angular would be best. But for your application as long as it's sealed well and fans can pull a good vacuum and decent cfms I think you will be ok. Most of those expensive polished aftermarket shrouds are same shape you made. Some guys get away with attaching fans to rad with no extra shrouding, I wouldn't hesitate to try as is with rubber seals. Cheers.
 
krazykuda said:
You are only two dimensional on that shroud, you need to add depth in the third dimension or z-axis.

Here's a sketch to show what I'm talking about. You have to swoop the back face of the shroud like a funnel going into the fans. You want a slope, not a flat brick wall for the air to run into...

View attachment 1714792356
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Hey Kuda,
I don't think I have ever seen the room to do that with our cars (not much anyway)
It'd be nice if we did though. :D

Dual fans side by side might give a little more room though.

I know one thing.
As much as a person would like to "Git er done" I wouldn't do it till the engine was in there, or it could very easily need to be done different after all that.
 
TrailBeast said:
Hey Kuda,
I don't think I have ever seen the room to do that with our cars (not much anyway)
It'd be nice if we did though. :D
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It's a little exaggerated to prove a point, but you can try to apply the concept as best you can.

Maybe put a more gentile radius on the back instead of 90°.

Try to copy similar to the stock plastic geometry which is limited depth also.

You should have some depth to work with, as now you don't have a mechanical fan hanging off the front of the water pump and can use some of that depth....

Try to add a little more radius to your bends for the back face instead of sharp corners. A little more radius can help...
 
TrailBeast said:
I know one thing.
As much as a person would like to "Git er done" I wouldn't do it till the engine was in there, or it could very easily need to be done different after all that.
Click to expand...


Yes, you need to look at the "end package" to figure out your degrees of freedom to work with...

I agree to have the engine and radiator installed to see what kind of room he has to work with....


If you use the sharp back wall angle, it may work. But you will loose some cooling capacity of your radiator from the partial restriction to airflow.

But it will be more efficient if you angled/swept the rear face to improve airflow. Then you are making the most efficient use of the whole radiator, and not partially restricting air flow with the "brick wall" for the air to run into. a little slope may help increase airflow and efficiency of your radiator...
 
krazykuda said:
Yes, you need to look at the "end package" to figure out your degrees of freedom to work with...

I agree to have the engine and radiator installed to see what kind of room he has to work with....


If you use the sharp back wall angle, it may work. But you will loose some cooling capacity of your radiator from the partial restriction to airflow.

But it will be more efficient if you angled/swept the rear face to improve airflow. Then you are making the most efficient use of the whole radiator, and not partially restricting air flow with the "brick wall" for the air to run into. a little slope may help increase airflow and efficiency of your radiator...
Click to expand...

Agreed.
My electric is centered on the radiator and no shroud since the fan is huge, and I have about 1/2 inch between the fan motor and water pump pully (4 inch thick fan motor) and small block motor.
So in theory, if I ran duals (side by side) I would have a few more inches to play with because the electric motors wouldn't be in the way.
I'm not turning this to be about my car, just thinking about the OP's possibilities.

He might consider one way vented above and below the fans also, (depending on how it does on the hiway)
 
Ive done what Jpar is wanting to do with the fans and I ended up having over heating issues. My set up had twin 10" fans that Perma-Cool claims moved 400 sum cfm each. The shroud was not allowing enough air flow thru the radiator at speed. It was way to restrictive. I could had cut more holes in the shroud but just opted to go back to the stock fan with a shroud. I just dont want to see anyone else run into this problem, my thread is below with pics of the setup I had.

http://www.forabodiesonly.com/mopar/showthread.php?t=277443
 
I wouldn't consider fans with less then 2000cfm between the pair for a mild build, hence why I initially asked about the fans capabilities because this would be all for naught if you have a pair of crappy fans. 3000cfm and a four core 26" rad for serious hp, this will move some air ( no heating issues on the hottest days). Fans that move 1000-1500cfm aren't cheap for 10-12" sizes but many come with their own shroud ($150-200each for quality brands). But, to not have the dreaded overheating headache they are worth it IMHO.
I'm running a pair of 1500cfm fans, I've had a wire come loose and only one was kicking in, it started to overheat. You can never go to big with fans.
 
Damn, just noticed I typed 400. Sorry I meant to say 2400 cfm each in my post. I still blame the restrictive shroud as the reason I overheated.
 
straightlinespeed said:
Damn, just noticed I typed 400. Sorry I meant to say 2400 cfm each in my post. I still blame the restrictive shroud as the reason I overheated.
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LOL, I was going to say you'd barely keep a slant 6 cool on a 40F day with a pair of 400cfm fans.

A pair of 2400cfm fans and not cooling? Definitely was some air flow issues there. Or was one pushing and the other pulling? :p LOL
 
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