[Gooserider]

My reccomendation for all multiblock systems, especially if there is not much data on a given combination of blocks is to do "Bucket testing" of any reasonable combination of components to see what gives the best flow rate results.

Bucket testing consists of simply building up a system with the components you'll be using, with the exception of the pump intake and system output. The intake should connect to an effectively unlimited water supply, the out put of the water system (which would normally go to the pump intake) should be a hose that can be aimed into a bucket. Ideally the block positions and hose lengths should match what will be used in the system, but it is OK if they don't as long as they stay about the same for all tests. To do a test, simply set up a test configuration and get it running long enough to purge any air out of the setup. Then put the output hose in a bucket, and time how long it takes to fill. If you know the size of the bucket, it is simple to calculate the flow rate.

Try different combinations to see what gives the best flow rates, both for the system and the individual blocks. IMNSHO, a few tests will beat all sorts of theoretical discussions.

That said, here are some of the guides that I use...

1. When picking a pump, high head is more important than high flow, almost to the point where the flow doesn't matter that much.

2. Priority should go to CPU cooling, then GPU cooling, followed by everything else.

3. In a series system, the flow will be NO MORE than what is allowed by the most restrictive block.

4. In a parallel system the flow will be the sum of what can flow through each block, (up to the input flow)

5. A restrictive block in series with a non-restrictive block will kill the flow in the non-restrictive block.

6. Restrictive blocks will allow more flow in parallel, non restrictive blocks it doesn't matter that much between serial and parallel.

7. In general, you want all the flow through the CPU blocks, but can afford to split up the flow through the other blocks.

In my system, I had two moderately restrictive CPU blocks, and 4 highly restrictive drive blocks (no GPU or NB blocks at present) my pump is an Iwaki MD20RT, which has 14' of head, and more free flow volume than I could use. The drive blocks were so restrictive I knew I didn't want them in series with my CPU blocks, but that if I put them in parallel they wouldn't reduce the CPU flow measurably. This violated guide #7, but in this case I can get away with it. With the CPU blocks in series, I had a total flow through both blocks of 3GPM. If I put them in parallel, I got a lower flow of 2.5GPM per block, but the total of 5GPM was better for the system overall. Splitting up the drive blocks also improved their flow, so I ended up with 4 branches, two CPU branches at 2.5GPM each, and two drive block branches at about 0.2 GPM each, giving me a net system flow of about 5.4GPM. This is an extremely good flow rate, and even approaches the upper limit of what is reccomended for my size tubing....

Gooserider


I found that if I put