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Eheim water pump........80gph

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Feb 1, 2001
Hi people,
wanted to ask one more question.
Is 80 gph enough for water cooling solution?
I have read reviews on Eheim 1046 pumps in many places and they seems to be good performer with almost no noise....but little pricey(42 + 5 s/h at petwarehouse). They also have Eheim 1048 which is capable of 160gph for 14 dollars more(56dollars).
Which one should I get? Do I really need that much of gph(over 100gph) for water cooling?

Thanks for any info.
Pumps are rated with ½” fittings. You are most likely going to use 3/8” ID tubing and the fittings have and ID of ¼”. Your pump’s flow will be cut by a factor of four. Every turn in the plumbing also takes its toll on the flow. BUY A BIG PUMP. You can always restrict the flow later.

As an example, my system with 2 feet of lift, a Danger Den block and Cooling Cube. The first pump in the system was a Rio 800 (inline) rated a 133 GPH @ 2’. My temps dropped 3 degrees C by switching to a 550 GPH @ 2’ pump. Restricting the flow of the 550 GPH pump raises the temps. What does this tell you? BUY A BIG PUMP!
I have a 80gph Pondmaster pump that has a flow control valve...accordig to specs the thing does 60gph @ 2ft of head...i've adjusted the flow rate from 20gph to 60gph and didn't notice any change in temp...
I just got my eheim '46 yesterday. Spent a good hour playing with it

The flow rate really shouldn't matter, as long as it can make the 'head' of the system. The flow rate doesn't matter, since the water doesn't instantly pick up heat from the waterblock (think of how long it takes water to boil - same principle). Slower flow in the waterblock would help, in it would allow more heat to be taken from the block. Mr Goat's comments support this.

Colin's heat drop may have resulted from going from a submerged pump to an inline (but I can't be sure - not stated).

My drop in temps is do to the increased flow. The Rio pump was modified and inline, not submerged.
Fast flow, IMO, doesn't cool better...the water doesn't have time to dissipate the absorbed heat when going through the rad...that and 550gph is too fast for that size tubing...turbulent water flow is bad for cooling
My tests and experience say otherwise. There are others that have achieved results similar to mine. While I don’t know if the others have my engineering background, from what I have read, their methodology is scientifically sound. With all do respect, your humble opinion is just an opinion.
Are you sure that you conducted a controlled experiment?

If you have a engineering background then please bestow you thermodynamic knowledge upon us...
Yes I conducted a controlled experiment. The only thing that changed was the pump. Of course this was stated in my earlier post. My system does have a large amount of surface area in both the block and radiator, which allows for more efficiency with a high flow of coolant. May I suggest a quick look here http://www2.apex.net/users/timwhita/flowrates.html

As for a long treatise in thermodynamics, I really don’t have time for it now. My wife and I leave for our second honeymoon in the morning. Besides, the results should be enough.
550GPH? That sounds little too much for me. I was thinking around 160~200 MAX. I got this Eheim1046 with 80GPH rating just because of the good review page on the watercooling section here on overclockers.com. I was going to buy the 1048 with 160GPH but it costs too much. (56 + shipping) So I just decided to go with the 1046.
I have a dangerden amazing waterblock with cooling cube as well.
Oh yea....what about noise? One of the primary reasons for watercooling is because I hate the noise of the Delta 38cfm fan so bad. I want my system to be as noiseless as possible. How loud are those mag drive 250GPH pumps? If those Mag-drive pumps are very quiet like those Eheim pumps, I can return my Eheim1046 and get the Mag-drive 250GPH instead.

Thanks for all the infos.:):):)
“Sounds” is one of those words like opinions. Until you have spent your hard earned money and tried it yourself, it does not hold water.

Eheim, Danner, etc. are all quiet magdrive pumps. From what I have been able to determine, they are all manufactured by the same company.
a faster water flow has nothing to do with cooling unless you have a way to cool the resivore. Water blocks are very ineffective unless you a have a thermistat, just like a cars cooling system. If you take out a cars therm. the water will continue to circulate and get hotter and hotter till it overheats, but with the therm. in place the water flow is restricted so it has enough time to absorb the heat and then it is relased to the radiator. If you realy want to make a diff. with a water block, put a fish tank chiller on the water line. They a used for cold water fish tanks.
No - the thermostat in a vehicle is to allow the engine block to rapidly reach optimum operating temperature and provide efficient combustion (less pollution products), and rapid heating of oil so that it lubricates more efficiently. Once the correct water temp is reached then the thermostat opens to allow circulation of the coolant to the radiator. The cooling system is actually designed to keep the engine at it's optimum operating temp under normal operating conditions, but have enough headroom to cool it under heavy work loads or high ambient temperature conditions.

Optimum water cooling performance in the computer is a balance between rapid fluid flow through the waterblock (but not so fast as to cause laminar flow which will reduce the efficiency), and a slow flow through the radiator to allow cooling of the fluid, the ideal radiator would hold a large amount of fluid and would be based on a single pass multiple parallel tube/fin design as in an automobile radiator rather than a multi-pass type.

The exchange of heat from one medium to another is basically controlled by a couple of principles. One is rate of thermal transfer through a medium, the other is thermal transfer from one medium to another. Whether it be air or water that is absorbing the heat, the higher the flow rate the better the cooling - up to a certain point. In the radiator you can achieve this effect by either slowing down the flow rate of the water inside the radiator or increasing the air flow through the radiator fins - or both.

Thank you for pointing out the obvious. I could not have said it better. I think my wife will thank you to since I won’t have to spend a bunch of time explaining things.

REMEMBER THIS, pump sizes in the public’s eye are generally dictated by what’s on the “kit” market. This market is profit, not performance motivated. Leufkens is a prime example. Grab a physics book and read. Most marketing is fiction, reality is truth. Marketing will rip you off, the truth will set you free.