Fan PQ curve testing - Part 1

[Martinm210]

ei martin any chance of testing some foam alu mesh filters? i wonder how restrictive they are

I almost need to get a slightly different setup going to measure pressure drop on stuff like the radiators or other stuff like fans. My little heatercore pressure drop line is only approximate based on actual CFM numbers, but even that I have my own concerns with accuracy. I think you really need pitot tubes and a large flow chamber to measure restriction and pressures accurately. My little setup has it's share of error, it's doing ok, but I'd do it differently if I were to do this all over...

Unfortunately, I think I trash canned the few filters I did buy a while back, they seemed to be alot more restrictive than I thought, maybe those aluminum types are better. The only thing I will run on my fans is the simple wire fan grills, I think those are pretty harmless, but I don't like anything more restrictive. I guess it makes sense when you compare pressures.

The very strongest fans can only produce less that .25" of Water, where many pumps can produce over 200" of Water pressure. This is also why I had such a hard time with measuring pressure. It wasn't until I bought this 0-.25" pressure gage, that I could even measure it somewhat consistently. My dwyer 0-20.00 digital manometer was too high pressure oriented to read fan preassures. To do this really right, you'd want one of the super sensetive 0-1.000" manometers capable of .001" resolution.

Anyhow, I avoid filters. Unless you're going to build some sort of rad box that'll hold very low restriction large household style filters. Unlike water flow rates, air flow rate is pretty significant and with the tiny pressures produced by these fans, restriction is also much more important. I was pretty amazed that you would see a performance difference in a radiator by simply changing the FPI one or two folds per inch, but it does matter. This is all due to how sensitive fans are to restriction, particularly slow speed stuff.

Anyhow, I'll try to get a few more runs done this weekend if I'm not stuck at work...I'm not planning to buy any additional fans or parts for the time being though. Need another little vacation, then I'll get back at this again.