flow v.s head

[nikhsub1]

Originally posted by fhorst
Hmm, it looks to me that the eheim 1048 gives 5L/m and the 1250 6L/m (at a higher presssure drop) (with the WW, big arse and 2m tubing)

only 20% gain with a double rated pump.....

Well double rated max flow at zero head, which for our purposes means absolutely nothing. The 1250 only has 1/2 meter more head than the 1048 and that is the only reason why the 1250 flows a tiny bit more.

[georgeteo]

Looking at the head vs. flow chart, the 1250 would def outperform the 1048, simply because the curve is a gentle one compared to the 1048 which has a steep drop off. But then again, how do we measure performance gained from using a stronger pump as opposed to a weaker one??

Performance should be proportional to overclocking ability. (quote from a friend )

Performance is also dependent on the components that you choose. No point getting a super pump for the restrictive Cascade block. The Cascade does not require high flow rate for it to reach near peak performance as opposed to the WW. In fact, a negative effect would occur as the stronger pump would dump too much heat into the water.

Choose the pump that is right for your system based on you components. e.g. If u have losta tubing and free flowing blocks, try to get a stronger pump. But make sure your Radiator is up to it in removing the extra heat dumped from the pump. If you utilize a smaller radiator, I suggest that u stick to the smaller 1048.

[Skulemate]

I know it hasn't been officially tested, and I'm sure that Cathar has a more detailed answer, but I'd assume that the Cascade would get a great boost if paired with a pump beefy enough to really raise the jet velocity inside the block (i.e. keep the flow rate high).

[pHaestus]

George: The smaller radiators are often MORE restrictive not less. Best bet is to look at the C/W vs. flow rate curve for your waterblock, estimate the resistance from all fittings, res or T, radiator, and waterblock and then choose a pump that will get you past the low flow/low performance region of that C/W curve.

My approach is to try and avoid as much resistance as possible in fittings and hose and plumbing and rad and get by with a smaller quieter pump.

[georgeteo]

I think you got me wrong bro. What I mean was that if you think that your setup would benefit from a Big Arse Pump, make sure u have a Big Arse Radiator to cope with the extra heat dumped into the water.

I am personally using a Sicce Extrema 35Watt (8.2ft/660gph) for my Swiftech 5002A and 50 blocks. Rated at 35Watts, the pump is heating up the water like a GPU. But I don't think my blocks would perform as well with a lesser pump. My Big Arse Rad (4fans 7v push pull) helps neutralize the pump.

The beauty of the cascade is that it performs so well even with low flow rates. I'm sure Cather would concur to that statement. I would also believe that every enthusiast would want to stick in the most powerful pump into his system in the search for better performance. But at what cost?? Downfalls are noise, increased cost, size and the all important heat.

The cautionary statement is .... Sometimes bigger ain't always better ... that’s all I'm saying.

[nikhsub1]

Originally posted by georgeteo
I am personally using a Sicce Extrema 35Watt (8.2ft/660gph) for my Swiftech 5002A and 50 blocks. Rated at 35Watts, the pump is heating up the water like a GPU.

If you run your pump inline, you are only dumping a fraction of the pump heat into the loop. Submersed, well then all 35W of it will go into the loop.