Multi-pump tops... y-fittings?

[M.Beier]

Hi guys, I am buying a bunch of used pumps these days... Laing D5, tops for 2 of them, cost big bucks... So tell me, any difference from buying one of those expensive tops, to using a Y-fitting before pumps and another after....?
Should give exactly the same performance, don' it?

I was thinking about buying 4 Y-fittings, in plastic...

Use 2x Hydor L20 (small cheap pumps), so why these suckers? They do -30C without breaking.... but the weight of the water when being frosty isnt something they are so happy with, so two would help a heck of alot for the flow I bet.... Waterchiller

I got another setup, which I will break into two...
Laing D5 + Laing D4, Y-fittings... This along with a Mo-Ra 2 radiator... To cool 1-4 GPU on my benchbed, along with a CPU.... Thinking maybe breaking her up into a 450L/H pump for the CPU only, paired with a 240mm radiator....
What say you?

The ram cooler will be on a loop without a radiator, but with 300ml resovair, should be good to keep a Corsair T30 cold for many hours?

[Church]

Dual pump top price IIRC was lower then price of 2 individual tops. +It gives you more compact mount possibility. Performance wise it's almost same as individual pumps connected serialy with tubing.

[M.Beier]

Dual pump top price IIRC was lower then price of 2 individual tops. +It gives you more compact mount possibility. Performance wise it's almost same as individual pumps connected serialy with tubing.

Will serial or parallel give best performance?

[BrokenArrow]

Will serial or parallel give best performance?

Serial.

[Creekin]

+1 ^

[Church]

Serial doubles pressure, parallel doubles flow. In real LC loops i'm guessing resulting flow will be similar, ~ 1.5x single pump. BUT! serial also gives pump redundancy (though some have told that with parallel part of flow with one failed pump also will go through loop, but i somehow still think that in parallel dual pump connection most of remaining pump flow will go least resistance route - subloop with failed pump, like shorting in electronics, instead of whole loop with way more resistive waterblocks).