Gooserider - agreed with almost everything, and especially with this:
I only can't agree with using 3/8" tubing as 'normal' or "standard' and i can't believe you can say that is possible when spliting got to even lover diamater. Never! 3/8" tubing is restrictive as hell itself! No wonder all well experienced WC guys going with 1/2"! I would recommend to avoid 3/8" at all. Of course there is no point of avoiding it, when your rad(s) have internal diameter of the pipes 7mm (2/8"), as mine...
Thanks for the kind words....
First off, it is possible that you missed my point that it is possible to reduce the diameter WHEN SPLITTING a flow - For instance a CPU block with a 1/2" in and TWO 3/8" outs. Small hoses can be nearly as low restriction as large ones, IF you use enough of the small ones. I'm not sure off hand about metric sizes, but if you look at inch sizes, and calculate the cross section areas, two smaller hoses have about the same area as one of the 1/8" larger diameter size. In other words, two 1/4" hoses are about equal to one 3/8" hose, two 3/8" hoses roughly match a 1/2" hose, etc. The two smaller hoses are SLIGHTLY more restrictive on paper due to their greater wall surface area but in the kinds of lengths we are using in a WC system this isn't a big issue, and the problem is eased even further by the next point.
Secondly, at low flow rates, a smaller hose doesn't offer significantly more flow restriction than a large one. (for any given hose size, the flow restriction it offers is a function of the flow rate, which is determined by the pressure on the hose) If you do a two way flow split, each hose will have half the flow rate that is seen in the 'parent' hose (assuming the two loops are the same). The lower flow rate in each loop will reduce the effective restrictiveness of any blocks etc. in the 'child' loops. While some GPU's are now approaching the heat output of a CPU, most are still fairly low power, and none of the other major W/C targets are high power, so high flow cooling doesn't really offer any advantages for the rest of the system.
Lastly, as many have pointed out, the larger the hose size, the more hassle it is to work with. Fat hoses are harder to route, take more room in the case, and tend to block access to other parts. So why use them when they aren't really needed? A smaller hose is much easier to work with when dealing with tight areas like a drive cage, or getting into an NB. If really going all out w/ W/C hardware, stuff like mobo FET's and RAM can benefit from even smaller hoses - after all do you really need a hose that's bigger than the part it's trying to cool?
My guess is that the Zalman Reserator pump/radiator is the quietest of them all. It's hard to say this for sure though, as I haven't seen acoustic measurements yet.
Funnily enough Zalman Reserator and their WB2 also outperforms Eheim 1048 + Danger Den RBX + big active radiator (according to a test at Nordic Hardware).
As pointed out in the other thread, those great results were obtained by putting a FAN on the Reserator - seems to me like that kind of defeats the purpose of having it.
If you look at the graphs in the review carefully, you will notice there were THREE sets of results, one labeled "RBX", one labeled "Reserator" and the third just marked as load and idle. The review didn't make it real clear, but the really good 'Reserator' results where the Reserator load was about the same as the RBX idle were actually 'Reserator PLUS FAN' results (what sort of fan wasn't specified - I was less than impressed with the entire testing section of the review - poor methodology and lots of missing data) the first set of results labeled load and idle that were acceptable but no where near as good as the others were the results for JUST the Reserator, which is presumably the way most SPCR folks would want to use it.
the zalman is a 3/8", thats not acceptable!!!
Depends on the design Seal... I agree that 1/2" is appropriate for a high flow volume system, which is probably going to be the most effective at cooling. However large hoses are ONLY a significant advantage in a high flow system, if the system is low flow the hassles of the larger diameter far outweigh the marginal benefits. If you look at the specs on the Reserator, you will note that it is designed as a very low flow system - the included pump is only rated at 300LPH into a 0.5 meter head (~1.5 GPM into 1.5 feet) By the time you figure the flow restriction into the equation, I would expect to see ACTUAL flow rates on the order of perhaps a third of that, which is low flow by any standard. For that flow 3/8" is fine.
Thank for the advice trodas. I actually had too much flow with 1/2" hose, the water didn't spend enough time in the rad to properly cool.
That I have trouble believing, as this is a topic that has been really beaten to death over on ProCooling. The main thread on it is longer than FanControls controller thread
The basics are that the water in any given circuit will spend the same %age of time in the rad regardless of flow rate. The faster the water flows, the less time it spends in the block getting heated, but it still gets cooled in the rad so the water entering the block is cooler. Since temp differential is what drives the rate of heat transfer, the cooler the water is when it enters the block, the more heat it will grab from the CPU.
That said, some of BillA's testing did show that some setups did tend to have a 'sweet spot' where the cooling was best, but the better the rad the less likely this was. Also note that cooling is an asymptotic function, the closer you get to theoretical perfection (ambient temp at the CPU), the harder it is to get better. Thus increasing flow on a system that is already working well might or might not show any significant benefits.
BTW, the Chevette core is good for it's size, but it is not all that low of a restriction. It's dual pass, with a fairly low number of tubes. A larger rad with more tubes will be lower restriction, especially if it is single pass.
I'm bout to order a pump.. 1048 or 1250
I have a 1048... it makes really no noise, just vibrates alot.
Does the 1250 do teh same with just mroe vibration? My loop is going to be very low resistance besides the whitewater (gonna wait for it to be in stock).
I'm going for very very quiet, if 1250 is noticably louder i'll get the 1048. Would you say its possible to have a 1250 in a silent system? I'm having trouble getting an idea of the difference between the two.
Also why can't you wrap foam around a pump, doesn't the water flowing though it cool it? I don't see hwo the pump would heat up with when its full of cool water.
I don't have the specs at hand, but IIRC, the 1250 moves more water and has a slightly higher head pressure than the 1048. Head pressure is the more important figure, higher is better, and will translate into better ACTUAL flow rates. I haven't heard either pump, but the reports I've heard say the 1250 is slightly louder, but not greatly so.
As to wrapping foam around the pump, much depends on the type of pump. Some pumps are not submersible, and may depend heavily on air cooling, such as Iwaki. Others mostly get cooled by the water going through them, such as the Danner MAGx series pumps, and most submersibles. Giving a Danner a foam blanket probably wouldn't hurt it much, but I suspect it would cook an Iwaki, which tends to run hot anyway. Another aspect to consider is that you really don't want to transfer any more heat from the pump into the coolant than you can help. Any heat that you can transfer into the air instead of the coolant is heat that doesn't have to be dissipated in the radiator, and isn't raising your coolant temps. Wrapping a pump in foam is going to maximize the heat transfer to the water. (This is the same reason why many people don't like using pumps that run submerged, as they inherently have to transfer all their heat to the water)