I suspect that there are some low restriction waterblocks for which the 1046 is not as "below the knee" as you mention.
The curve for the Swiftech 6000 comes to mind - there seems to be very little additional benefit as flows increase.

C'est mon petit doigt qui me l'a dit :p

I have the PQ curve of the DDC and the EHEIM 1250. They cross themselves at about 5.2 lpm. (first I estimated the PQ curve of the cascade from the cathar's results with the EHEIM 1250,1048 and MCP650 and I used it with the PQ curve of the DDC, and I saw 5.2 lpm like for the 1250)

I used the power/flow curve from rosco to determine the heat given to water by the pump (I used the same efficiency than cathar with the MCP650 alias D4) and found about 9W

5.2 lpm, 9W, same figures for the DDC and the EHEIM 1250, so same perfomances :p

Buzz, you have the PQ curve for the DDC at 13.2v.

Somewhat different, and lower, at 12v where the block tops out at less than 6LPM, and peak pressure is ~20% lower.

Using the 13.2v PQ curve is fine, but be aware that it is a non-standard voltage in PC's and must be achieved through an externally powered means.

I always found it somewhat odd that the DDC was "originally designed for PC cooling", yet somewhat misleadingly all the PQ curves and values reported are at its maximum 13.2v level.

Still, even if the DDC is the equal of the Eheim 1250, that still leaves a fair amount performance gain to be achieved through the use of a stronger pump for blocks.

The pressure vs C/W curve for the Swiftech MCW6000 is very flat in comparison to many other blocks, and I would hazard an educated guess that it is even flatter than many of the European high-restriction low-flow blocks.

Too late now, but I'll run some figures with the MCW6000 tomorrow.

(semi)ok Buzz: I dont think the DDC puts out 9w - it only just absorbs that much. (not that it would make much difference at this level)
My little finger does agree with yours in that it will be a different scenario for a 1a-hv2 type block though ;)

So the best noise/performance choice would be two 1048 pumps in series? Or do they become a lot noisier when placed in series? Does anyone have experience with 2 1048's in series?

Probably not. Even if the flow curve is perfectly flat the transistion from a 1046 to a 1250 looses by just .3C (remember we're dealing with a 9 w pump here, which isn't a huge problem for a large-ish radiator). If theres even a slight downward curve on the C/W per flow curve, the block will pick up the couple thousands of a C/W needed to offset the 7.5w gain.

Of course, if you assume a small enough radiator, all bets are off :)

This is a very nice guide! The only thing I question is the estimation of heat dumped directly into the water by the pumps.

which is exactly the basis for this whole exercise
at 3 gpm and 150W I'm looking at a deltaT of 0.20°C, so at 10W the expected deltaT would be 0.0133°C
at a more reasonable/measurable flow rate of 1.5 gpm the deltaT is 0.38°C, so 10W would be ~ 0.0253°C
I would not be too uncomfortable at differentiating between 5W differences, but lesser increments would not be 'measurable' with the equipment I have

next time I'm into pump testing I'll gin out some measured values

So, you're saying it makes sense to go with the 1250 because it might perform about the same as a 1046 in this situation?

Cathar,

Would you still maintain your recommendation «Single 120mm radiator: First choice: Swiftech MCP600 or AquaXtreme 50Z. Silence Choice: Eheim 1048» for a radiator that followed somewhat the ideal specs you mentioned in a topic sometime ago: 160x160x32mm, or 160x160x45mm?

Cathar
Not happy with the data.
Particularly the assumed constancy of heat imputs
Are the "pump heat" to water measured or a dream?

Eheim 1048, 1250, MCP600 @ 12.0 and 13.8, MCP650, Iwaki MD-30RZ are all measured values, since I actually had those pumps in hand.

Eheim 1046 is an extrapolation based on the other Eheims.

The rest of the Iwaki's are extrapolations based on a 63% of rated input figure as determined from testing the MD-30RZ, due to the common shared separated magnetic armature design. The MCP600, which is also of similar design, as well as the March 893-09 that I have here, all have a ratio of in-line heat to pump motor input of around the 65-70%. Given the strong trend, I felt it safe enough to run with those figures.

In the full article I had already explicitly explained that which were measured values, and those which were extrapolations.

I really wanted to include the Danner Mag 3, but I did not feel comfortable with assigning a pump heat transfer value to it without either measuring it, or having a number of other pumps from the same range to extrapolate from.

With a Cascade + rad in the circuit?
Not happy

With a Cascade, no rad.

Not happy? Get over it, or do better.

Happy that info is presented.
Always been a poor experimentalist, and now being slightly physically limited present zero.
However always hope for pure data

Les, I do know where you're coming from, although I do get a little frustrated sometimes with the perennial suggestions from you that I'm making this stuff up as I go along.

I'm happy to admit what's extrapolated/estimated vs what I measured. I am also aware of the variance of pump heat output as the flow rate changes. I chose to measure with a Cascade in the loop to provide a single value that I could use. Yes, it does not strictly apply, but in what I measured for the various pumps it offers a pretty good mid-point between stupendously blocked flow (trickle) vs open-flow, with those extremes varying by around 10%, and at most 15% from the values I measured with the Cascade in the loop by itself.

I don't have the time, or really the exacting equipment, to generate detailed heat vs flow graphs, so yes, I did compromise here and settle on a catch-all figure. Even given the heat vs flow variations, we're still only talking about 0.1-0.2C variations at the absolute extremes of the flow rate ranges for the >50W pumps, from what would be calculated given the simplified "mid-point" heat transfer figure.

As a cooling god you have to be extra cautious.
For example
I am curious about the statement "C/W"=0.003 fora 3.5mx3.5x2.5m room .
With brick walls i would make it more like 0.03c/w

F**k I hate the "cooling god" appellation.

No double brick walls here in Australia (well, not many).

0.003 with the door open accounts for it. Just a really, really rough measurement.

Close the door, and double brick the room, then yeah, 0.03 would probably be more accurate.

Apologies, didnt notice the 'knee' was very similar - i was under the impression it was steeper than the cascade by quite some margin.

I'll not critique an article I've not seen

some simplifications are apparent, which could be very significant depending on the system design
- in case
- in case, case air exhausted through the rad
- external cooling box
- actual flow rate

a biggish metal frame pump in a closed case will do more than just heat the water

hey pH / JoeK
can you change Cathar's title to "Cooling God" ?
sorry Stew, could not resist (better you than me, lol)

In so far as the amount of power used, and heat added to water, I see what you are driving at Cathar.

But 2 X 50Z => $160.00 USD + 30$ for power adaptor........and if you need a separate PSU to run the dual pumps, or just a bit larger & higher quality PSU to be sure of all working well...$$ more. So while the 2 X 50Z @13.8v will perform, they also cost at the same level as the MD30, or depending on PSU extra cost.......even a bit more.

The above is getting expensive quick. At this point the MD20Z is looking better when costs of such set ups are factored in.

The estimate you used for the 4 X 12cm fan rad seems to sell the core short of what I would expect of it. But such are estimates. And I understand you used the 120.3 figure as it's a solid set of numbers for the comparison. But a higher performing rad would reduce the pump heat effect of the larger pumps more. I'll have one before much longer, then I'll have a chance to see how good it is.

Not really fair for anyone to expect Cathar to have exact numbers in a thread asking questions regarding pumps not originally part of his test, or rads he doesn't have & his article isn't done yet anyhow.....gets crazy sometimes.

Will look forward to the finished article Cathar.

Any in case use of a Iwaki or panworld ......ect is going to heat up a system big time. But Niksub1 is about the only Iwaki user I've seen who had the pump in case. They are hard to fit to the point this isn't going to be a issure for many.

A properly designed rad box should, IMO, pull air through the rad before it passes over the pump cooling the pump. So the rad box should show better performance/temps.

Your last point is one very few have the equipment to messure Bill, but it's still important. Hope you'll be doing some pump tests soon.

This is a really good thread. G'night.

I would really only recommend the single AquaXtreme 50Z @ 13.8v, and not dual pumps. The differences between the two really is quite small (negligible), and certainly not worthy of getting a second pump.

The 20RZ is actually a lesser performing pump. I ripped those two posts at the start of this thread out of an evolving thread with little or no editing. The 20RZ I would not recommend over a single AquaXtreme 50Z @ 13.8v. I would only recommend the 20RZ in a DC powered format, which sadly doesn't exist, yet.

I apologise to all for the confusion. The statements in the second post of this thread are meant to over-ride the statements from the first post. I see that this is causing some unintended confusion.

Sell it short? How so? I have and actively use a 12" x 10" radiator here. I use 2 x Panaflo L1A's on it at 12v and estimate that my radiator's C/W is around the 0.020 - 0.022 mark with ~33dBA noise (based on manufacturer fan noise ratings).

Estimating a ~0.02 C/W with tolerable fan noise levels is not selling a 25 x 25cm radiator short at all, unless you desire to wear ear-plugs while computing. I would estimate that accounting for the radiator's inefficiencies you would need to be pushing at least around 150CFM through a quad fan radiator to achieve the 0.015 C/W figures I atrributed to it with strong fans. I assure you that achieving 150CFM through even such a large radiator with tolerable noise levels is not as easy as it may seem. Can always achieve quite fantastic radiator performance so long as noise is not part of the equation.

Yes it does depend a lot on fan selection. 2 or perhaps 3 X Delta 120mm X 38mm 1212HE fans at 130cfm do however offer a lot more air flow/pressure than lower noise 25mm thick fans. Also more nosie, but then that is what my reobus is for. And even with them dialed down to 80cfm each @ approx 35dba, I expect they offer better pressure than a 25mm fan can.

I'll have th core soon, I figure it's the best one to use with the Storm + Fusio + MD20.

Also note, I'll use a rad/pump/fan case which is 1" thick walled wood + 1" sound foam throughout & is some areas 2" sound foam. So it's ending noise levels isn't bad unless I turn up the fans.

geeze guys

the man goes out of his way to do a whole lot of work

and what's he get in return? silly questions and criticisms

let me say

good job

I concur. I look forward to the completed articles and graphs. By it's nature it's going to be more or less restricted to equipment on hand for Cathar, but I think I can extrapolate enough data from the graphs to make decisions for my own pump replacement options. Thanks for putting in the work!

Any notion if these numbers are loop dependent or not? I'd guess not - but that's a guess...
Yes I realize you only have a couple of loops to test in, but if you get approximately the same numbers for the same pump in different loops that'd be a strong indication...

cathar, based on this info would it be fair to assume that two eheim 1046's in series pushing a moderately restrictive loop would be a viable pump solution for a silent non performance loop?