370 block restriction

CPU water cooling blocks...
erratic
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370 block restriction

Postby erratic » Thu Oct 20, 2011 11:16 pm

The 370 is reported to be a low restriction block and looks like it from the design, but the one I have doesn't seem to be that way in my loop.

With nothing but the pumps, res (452x2), flow meter, a 90 degree bend through a DT-XUTX4 cube, and ~60cm of 13mm hose, I was getting in excess of 10l/m.
Swapped out the cube for the GPU block got me over 6l/m.
Swapped out the GPU block for the 370 and the flow rate went down to ~2l/m.

It's just me, right?

[Koolance] James
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Re: 370 block restriction

Postby [Koolance] James » Tue Oct 25, 2011 2:46 pm

Hello erratic,

Any CPU block is going to have restriction. Based on some tests (by Martinsliquidlab) "the Koolance CPU-370 is average to average/low in restriction compared to the wide range of various blocks tested.".

Martinsliquid lab has also has a test for the LPM of the RP-452X2.

How are you reading your flow meter? What kind of GPU block are you comparing the flow to?(A GPU-200 will be less restrictive than a VID-AR699, for example)..

Hopefully the reviews/tests will help you determine what you should be expecting with your loop.

James

erratic
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Re: 370 block restriction

Postby erratic » Tue Oct 25, 2011 11:47 pm

Hi James, thanks for the response.

I'm aware that blocks have resistance and that review is part of the reason why I chose this block, since I wanted low-resistance blocks since my rad is pretty high resistance (I assume, anyway).

My concern is that with 2 pumps in series, my flow rate was going from +10 to around 2 l/m just by plugging in what is supposed to be a low restriction block!
With both blocks and 2 QDCs instead of the rad, flow rate remains around 1.9-2 l/m.
FWIW, the GPU block is a Koolance VID-AR687 and its restriction seems fine.

Flow rates are measured with Koolance's FM17N. I'm not that concerned with absolute accuracy but the huge relative drop I'm seeing and which I believe is abnormal.

[Koolance] James
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Re: 370 block restriction

Postby [Koolance] James » Wed Nov 02, 2011 10:10 am

Hello erratic,

Can you confirm that the micro-fins on the 370 are in the proper flow direction (if you look into the block through the IN, you should see the fins perpendicular to the 1.5mm slit in the impingement plate)? Also, are you sure you are using the IN/OUT ports correctly?

The first block usually causes the most restriction, so removing the radiator (if it's last) may not reduce the restriction that much.

I definitely wouldn't say that 1.9-2l/m is a bad/too low of a flow rate at all. What are your temperatures like? I think if you're happy with your temperatures, flow rate shouldn't matter very much.

James

erratic
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Re: 370 block restriction

Postby erratic » Fri Nov 04, 2011 2:19 am

Yep, fins are aligned and I'm going in the central fitting and out at the top.
CPU cooling is fine, but the GPU needs to be downclocked to remain stable.

Since games are generally GPU limited (well they are with a 2600 / 6870 combo) I'm thinking of removing the impingment plate. I know it will negatively affect CPU cooling, but it's the GPU that is the bottleneck.

I am suprised that two d5 pumps aren't pushing that much water though.

nuts, the flow meter has packed up now :(

Tuthsok
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Re: 370 block restriction

Postby Tuthsok » Mon Nov 07, 2011 7:56 pm

Hi,

I get 2.1 to 2.4 lpm using 2 PMP-450 pumps in a RP-452X2 rev 1.3 set up in serial. They are pushing the coolant through 2 3x120 radiators, 2 evga 590 hydro copper blocks, a Koolance 370 and 8 sets of VL3N QDCs (among other fittings).

What you are getting seems reasonable to me. I was wanting to get to that 1 gpm point that gets mentioned lots in forums but the truth is that this flow rate keeps my system quite cool. After Folding@Home for 10 hours on all GPUs and my i7 990x all core temps were still below 50C.

I also have a RP-401X2 rev 1.0 with a pair of PMP-400 pumps. At some point I am going to try this out in my loop again. Before I added a second radiator (and the RP-452X2) I was getting about 3.0 lpm with the pair of PMP-400 pumps. While the D5 pumps have a higher maximum flow rate I may find that I get a better flow rate with the DDC pumps due to the higher head pressure they have.

Not sure when I'll try it out though. I need another couple of QDC male threaded fittings to add to the RP-401X2 so I can just swap it out after filling it outside the system.


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