Impedance of a radiator?

I've been trying to find impedance measurements of mainstream radiators (black ice, swiftech, etc) to get an idea of what fan to pair them with.

Does anyone know if someone has done testing to actually get some numbers?

I'd love to do some testing of my own but i can't afford a manometer

http://www.overclock.net/water-cooling/518786-huge-radiators-roundup.html

Is this what you are looking for? Gives you an idea on the chart of what fan speed will do what with which radiator.

Generally, the Fesers are great with low RPM fans, Swiftechs do fine with mediums, and Black Ice radiators like high RPM fans.

Just go by fin density. the more fins per inch, the more CFM and pressure you will need to effectively utilize the rads potential.

Just remember too, shrouds can make a huge difference in the amount of air and pressure needed.

doz said:

http://www.overclock.net/water-cooling/518786-huge-radiators-roundup.html

Is this what you are looking for? Gives you an idea on the chart of what fan speed will do what with which radiator.

Generally, the Fesers are great with low RPM fans, Swiftechs do fine with mediums, and Black Ice radiators like high RPM fans.

Click to expand...

This is a great review, but it's not exactly what i'm looking for. I'm looking for air flow impedance not water flow. I'm not too worried about water flow because I have a short closed loop and a fairly powerful pump. But I am worried about the fans as most fans seem to be low pressure and designed for circulating air. I could get over this by using a centrifugal blower, but the size makes it unpractical so i want to get an idea of the impedance of a radiator and figure out the best fan theoretically. I know the best/easiest way about this is to buy a bunch of fans and do testing but at the moment I have plenty of time to calculate numbers but little money to spend.

EarthDog said:

Just go by fin density. the more fins per inch, the more CFM and pressure you will need to effectively utilize the rads potential.

Click to expand...

Yes that is the general idea, but I'm being a little obsessive about it

doz said:

Just remember too, shrouds can make a huge difference in the amount of air and pressure needed.

Click to expand...

i'm factoring this into the fan i end up picking. I'll be making a fiberglass shroud that will be side enough to eliminate the motor dead spot and flow bypass.

Shrouds are helpful but hardly a huge difference. The best review I have seen give them about a 1c improvement over no shroud and my own experience bears that out.
There are great radiator reviews over at Extreme Systems. The Swiftech is the best bang for the buck. The XSPC or Thermochill are best all round. All three do nicely with low volume fans.

genec57 said:

Shrouds are helpful but hardly a huge difference. The best review I have seen give them about a 1c improvement over no shroud and my own experience bears that out.
There are great radiator reviews over at Extreme Systems. The Swiftech is the best bang for the buck. The XSPC or Thermochill are best all round. All three do nicely with low volume fans.

Click to expand...

i got big improvements with a shroud but i think the issue is the execution of it. if you don't properly seal the shroud, it will not be as beneficial

Depends on teh rad too and the fan steup. If you are bleeding air left and right, then adding a shroud could help more than 1C or so.

I really need shrouds for my setup.

http://martin.skinneelabs.com/Radiator-Fan-Orientation-And-Shroud-Testing-Review.html

Some stats on shrouds. 15% improvement is about typical... and can net a degree or two, which is reasonable considering thats about what the difference between a swiftech and more expensive radiator is (depending on fan speed)!

ascl said:

http://martin.skinneelabs.com/Radiator-Fan-Orientation-And-Shroud-Testing-Review.html

Some stats on shrouds. 15% improvement is about typical... and can net a degree or two, which is reasonable considering thats about what the difference between a swiftech and more expensive radiator is (depending on fan speed)!

Click to expand...

+++++ on this. Only Skinnee and Martin have done scientific tests. Besides that, low FPI works with lower RPM/CFM/Pressure fans.

yup every little bit counts.

so no one has seen any impedance measurements of radiators on the net?

Methinks the word impedance is wrong. We call it airflow restriction. A linkie was posted at Post #9 here, just go up a few posts.

So yes there is TONS of solid info, if you want to read up on it.

Conumdrum said:

Methinks the word impedance is wrong. We call it airflow restriction. A linkie was posted at Post #9 here, just go up a few posts.

So yes there is TONS of solid info, if you want to read up on it.

Click to expand...

they mean the same thing
impedance means resistance and can be applied to electricity or fluid dynamics.
i found general details about airflow restriction and know some theory behind it, but theory is useless with some numbers when you are trying to pair up parts.

Yes, it can be used in electronics too. We call it airflow restriction I guess, you can call it whatever you want. I'd use the test results of all the rad tests on Skinnees site and the extensive fan ones at XS and Madshrimps, and use the rad results with different fans to pick what you need. There is no conclusive perfect fit all test I know of. Watercooling a PC, part art, part hobby, and some very very basic scientific principals.

If you find it, please post it? It's not too expensive (few 100 dollars) to build a test rig like Martin and Skinnee have. The trick is to get all the fans and rads to test.

Get a XSPC RX rad and Medium Yate Loon fans, but only get the fans from Petras. That's my scientific advice.