I'm trying to figure out what pump I can use for silent operation in my new planned build. I'm looking at the flow restriction in my planned loop and using Martin's pump planning guide with his rule of thumb:
I'll break down all of my planned/estimated components in my loop:
|Component||Flow restriction (each)||Flow restriction (total)|
|CPU waterblock: EK Supremacy||
(source 1. ~0.6 PSI, difficult to tell from graph)
(source 2, the graph in the 6th picture. 65mbar @ 227 L/hr ≈0.94 PSI @ 1GPM)
|GPU waterblock: EK R9 290x||
(source: same as source 2 above)
|Radiators: Alphacool ST30 (2x 480mm, 1x 240mm)||
0.48 PSI each
0.08 PSI for 1/2" barb res
(source: source 3 above. assuming 3/8" is about the same)
|Tubing: 3/8" ID, estimated ~5'||
0.64 PSI per 10' of 3/8" ID
(source: source 3 above)
|Compression fittings: 14 total for 7 components (CPU, GPU, 3 rad, 1 res, 1 pump)||
0.01 to 0.02 (so, ~0.015) per each
(source: source 3 above)
|90-degree angles: I estimate I will make ~15 90-degree angles in my rigid acrylic tubing||
~0.065 PSI per each
I'd like to use the Swiftech MCP 655-PWM-Drive pump, which Martin describes as the "king of silence." However, the pressure head of this pump at 1GPM is only 4.6 PSI (and that's at 100%!), compared to my calculated 4.865 PSI flow restriction. From my understanding, this means that even operating at full speed (in which case, what's the point of the PWM?), this pump would still not be enough to achieve a flow rate of 1GPM in my loop.
- Are the above calculations being too conservative, i.e. overestimating the flow restriction?
I'm wondering about this because if I use this pump guide I get slightly different results:Warning: Spoiler! (Click to show)Quote:Pressure Drop figures for components
Radiators: 0.20 PSI each (the size of the radiator has no real effect)
CPU Block: 1.1 PSI
GPU block: 0.9 PSI
Motherboard block: 2.0 PSI (fullcover)
Fittings: 0.3 PSI for the entire loop
Tubing: 0.5 PSI per meter (3.3 feet)
So, 0.2*3 + 1.1 + 0.9 + 0.3 + 0.5*2 = 3.9 PSI
- If so, will the MCP 655-PWM-Drive be sufficient after all?
- If the MCP 655-PWM-Drive would be sufficient but just barely so (i.e. I would generally have to run it at or near 100%), it seems like it wouldn't be worth using this pump since in this case I wouldn't really be utilizing the PWM control. Would some other D5 like the Koolance PMP-450 be a better option?
- Should I instead get the Swiftech MCP-35X? With 6.36 PSI @ 1GPM it should definitely be sufficient. This is an often-recommended pump and it has PWM so I could dial the speed up or down as needed, but I've heard it's a bit noisier. Is it really that much noisier? Will I be able to hear it over my radiator fans, considering I'm planning to run my fans at very low rpm to achieve near-silent operation?
- Another alternative: 2x MCP 655-PWM-Drive in series, with a dual top. With two pumps I could easily dial down the PWM to run them at a much lower speed, or I can dial them up when necessary while gaming or benching, like I plan to do with my radiator fans.
Regardless of which pump(s) I get, I plan to use a foam base like this one to decouple the pump(s) from my case.
Any feedback would be appreciated!
Edited by Sir Awesome III - 11/19/13 at 2:25pm