[urgrandpasdog]

I am planning on making a rad sandwich (for different loops) out of two BIX rads with 86.5CFM Panaflos. Due to space restrictions, I can go with either of these setups

option #1
BIX
25mm Shroud
Panaflo
25mm Shroud
BIX

or

option #2
Panaflo
BIX
Panaflo
BIX

Which would give me the best cooling?

I am not asking whether or not the sandwich is a good idea, ONLY which of these fan setups would work best.

 

[Enigma8750]

Do your really mean 25 mm or 250 mm fans.

 

[Bellatrix]

#1.

 

[urgrandpasdog]

Quote:

Originally Posted by Enigma8750 Do your really mean 25 mm or 250 mm fans.

What???
I mean 25mm thick shrouds

 

[Veltri]

Seems like a good experiment. Let us know.

 

[urgrandpasdog]

Quote:

Originally Posted by Veltri Seems like a good experiment. Let us know.

I'm not experimenting, I'm asking which is better. I don't have the cash to pay for the components for both setups.

 

[thehighlander123]

if ur gonna make a sandwitch ur gonna need more than 86 cfm...

 

[drriddles]

First, I'm not an expert but there seems to be a little bit of reasoning in order here. Now, without knowing what you are cooling, it is difficult to guess at what your results will be in either case. But, if we assume that you are cooling your cpu with the first rad to receive air and that you are cooling 'X' watts then you are going to introduce warmed air to the second rad and subsequently may find that it is not as effective as air cooling for that loop because it cannot cool to a lower temp than the air it receives.

 

[urgrandpasdog]

Quote:

Originally Posted by drriddles First, I'm not an expert but there seems to be a little bit of reasoning in order here. Now, without knowing what you are cooling, it is difficult to guess at what your results will be in either case. But, if we assume that you are cooling your cpu with the first rad to receive air and that you are cooling 'X' watts then you are going to introduce warmed air to the second rad and subsequently may find that it is not as effective as air cooling for that loop because it cannot cool to a lower temp than the air it receives.

I am aware of this issue, however the warmer air coming off a rad is seldom more than 1-2C higher than ambient, and the second rad will be for a GPU loop, and GPU's are fine with slightly higher temperatures.

 

[urgrandpasdog]

Okay, we have a vote here for #1 and over at XS my sole reply said #2.

C'mon people, someone has to know about this stuff.

 

[jam3s]

Hi here are some stellar results that might help you with your question.

Done by martin, entitled, Fan Orientation and Shroud Testing

 

[ira-k]

#2. that will give you more air flow. Shrouds are more for optimizing the air flow. A fans air flow kind of looks like a do-nut with a dead air space in the middle, moving it off the rad a little helps to close that space, that way more of the rad surface area is used.

But using twice as many fans is going to give you a better bump I would think, especially with stacked rad's.

Its just hard to beat cfm and rad surface area for water cooling.

 

[drriddles]

Using Martin's radiator estimator shows that 2 fans are far better than 1. I don't have the link to it, perhaps someone else can post it. If you can get it then try it yourself.
Here's how I used it: I arbitrarily enterd 400 watts as a load and then set the fan speed to 1000 and a 20% shroud gain to get 10.59 water out/air in. Then I changed the fan speed to 2000 to simulate doubling the number of fans and removed the shroud gain to get 4.48 water out/air in.

You probably won't realize that much gain since it is stacked, but it does tend to show a clear direction to take.

Hope this helps

 

[urgrandpasdog]

Thanks ira, I think i'll go with that configuration. I really wish that I could do shrouded+dual fans, but this setup is already scraping 200mm

It's like a tower on top of my tower

 

[ira-k]

Quote:

Originally Posted by urgrandpasdog Thanks ira, I think i'll go with that configuration. I really wish that I could do shrouded+dual fans, but this setup is already scraping 200mm It's like a tower on top of my tower

I know it, my GTX has gutted 38mm fans as shrouds on each side plus the 38mm fans on top of them, its a thick rad,shroud,fan combo. Adding another rad into that mix would be wild.

A lot of guys never use a shroud, a GTX or any other made for WC'ing rad already has a bit of a set-off from the core anyway.

Shrouds are a great optimizer if you can fit them, but they wouldn't be better then another row of fans.

One thing you can do that will help a little is to pack the gap between the rad core and the rad sides with some neoprene or weatherstripping to close that gap. That will focus all the air through the core. When you get your rad you'll be able to see what I'm talking about. I don't really know if it helps much but it makes me feel better to seal it.

 

[urgrandpasdog]

I see what you mean about packing that gap around the core (looking at my swifty rads right here). I wouldn't know if it helps at all, but it can't hurt.

I was wondering if it would be beneficial to put a sort of seal around the edge of the fan where it makes contact with the rad, as it seems air could go through the little gaps created there instead of going through the rad?

 

[javier]

Quote:

Originally Posted by ira-k Shrouds are a great optimizer if you can fit them, but they wouldn't be better then another row of fans.

Exactly. #2 for sure, and I don't even think it's a question.

 

[urgrandpasdog]

Okay, looks like #2 hands down

And darn it ira, you need a +REP button

 

[ira-k]

Quote:

Originally Posted by urgrandpasdog I see what you mean about packing that gap around the core (looking at my swifty rads right here). I wouldn't know if it helps at all, but it can't hurt. I was wondering if it would be beneficial to put a sort of seal around the edge of the fan where it makes contact with the rad, as it seems air could go through the little gaps created there instead of going through the rad?

I used to use those cheap silicone fan gaskets that are used to quiet fans, I just cut the strip off that goes across the rad.

What I do now is just use a small bead of clear silicone to seal it all up. It scrapes off with a thumbnail when you need to clean it off., just don't get any in the fins of course. Its not really noticable once dried. Just pack it in the seam with your finger and scrape the excess off with you thumbnail once dried.

You could cut some out of thin card-board as far as that goes, like shirt card board and just use black magic marker on it. Thin foam, anything like that.

Some thin 1/8" black neoprene would be great if you have the patience to cut it out. You can get fairly large sheets cheap on eBay at times, I buy thicker mobo and TEC block condensation proofing neoprene from there sometimes.

But like I said I just use clear silicone any more, its a fast way of doing it, seals great and its easy to clean off.

Quote:

Exactly. #2 for sure, and I don't even think it's a question.

Yeah its hard to beat cfm, I don't think it would even be close either.

EDIT:
Quote:

And darn it ira, you need a +REP button

I'll settle for pic's when you get it all set up.