proving friend wrong

[Busty St. Clair]

yeah so my friend gustav on these forums doesn't know anything about wc and he keeps telling me that if i were to use a rbx water block I need a pump rated way above 300gph just for the waterblock and not the radiator and resevoir. he doesn't believe me that flow isn't as important for a restrictive block as head and he keeps saying that he can't wait till he sees my horrible temps when i build my wc system. so i just want to bring up the swiftech pump that many people on this section are happy with and is only rated 185gph but has 10.5gph

[johan851]

Yeah. Doesn't have a clue.

There are better ways to prove him wrong though - take a look at front page articles and waterblock rankings, for one thing. I don't know if there's anything I can say to change his mind, but there's plenty of data out there to prove him wrong.

Or you could just build the system and show him your 'horrible' temps.

[Busty St. Clair]

yeah but it will be a good 3 months before i build my rig so i don't know how to really prove him wrong.

[Joe Camel]

how about this:

have him blow up a balloon thru a straw with 1 BIG breath

then have him blow up the same using 3/4" hose (same length of hose as straw). same 1 BIG breath

assume HE is the pump with a constant GPH: 1 big breath (really CFM but...)

ask him which was harder to blow up...(duh)

since he has a constant GPH, he needed to produce more preasure (head) (you can have all sorts of fun with THAT one) not GPH to blow it up with the more restrictive (RBX) setup.

he had to blow harder (head) not more (GPH) to get the same results.

did that make ANY sence?:confused:

[infinity9]

http://phaestus.procooling.com/pqcurves.jpg

In the real world there is resistance that will reduce flow rates. As flow rates are reduced head is increased (pressure). So using an imp block will seriously reduce flow so you would rather have a pump with higher head so it can push the water through. Using a non-restrictive setup will work better with a high GPH pump though.

[Busty St. Clair]

yeah so i told him it but he is dumb and he keeps on saying a frontpage review for the dangerden rbx says use no less than a 300gph pump. and i tell him they just recommend that since usually the high gph pumps have higher head but you dont need 300gph you just need alot of head

[gustav]

well, I will admit that I don't know much about water cooling, but I do know how to read. I have checked out the front page waterblock/heatsink testings. I don't know how many times I told him to read it, but I couldn't get it through his thick head; he's lazy and therefor did not read it. Maybe Joe is wrong, but according to him, in the testing of the Danger Den RBX under the Overclockers.com waterblock testing, that the Denger Den RBX block: Test Results indicate that the RBX's pressure drop (or head loss) across the waterblock is moderate; resistance such as this means that Danger Den's RBX needs something like a 300 gph+ waterpump to function effectively, an even more powerful pump if system resistance is high due to other waterblocks and a high pressure radiator.

Denger Den RBX (http://overclockers.com/articles886/)

I'm not disagreeing that you don't need head - thats obvious, if you don't have push, were will it go? But, all head isn't good either. One extreme or the other can't be good. what good is a 500 GPH pump if it has little to no head? Likewise, it can have lots of head, but what good is it if it doesnt have much GPH? Generally, it is a good practice to go by what people recommend, especially the people who test the blocks and know what they're talking about.

[Busty St. Clair]

yes they recommend that much gph but if you have more head instead it will perform much better since it will have much more pressure which will help a lot in high resistence waterblocks and radiators. for instance the famous swiftech water pump that only gets 185gph. why would anyone get one if the 10.5ft of head didn't help more than a higher gph. so it doesn't really matter since a pump with 300 or more gph is rated that way with no resistence.

[gustav]

why not go with the gph pump the recommend that also has good head. you claim that most pumps with 300gph, have almost no head. i find it funny that many pumps here (http://www.dangerden.com/mall/pumps.asp) that are rated at 300gph or more have lots of heat. for instance, the Hydor L30 is rated for 320gph and has head of 75"...something to consider.

[Busty St. Clair]

it's kinda funny how little you know since pumps that are rated at 75'' won't perform as well as one with really high head and lower gph. since that flow isn't rated at it's max head it's rated at no restriction and there is alot of restriction in the average wc rig. since the more head you have will increase your flow in high restrictions.

[gustav]

hey all im saying is that i can read and im simply showing you that Joe recommends at least a 300GPH pump. now i dont know what you have against that pump, 75inches head is just over 6 feet. with 300gph, that would be the perfect match for the RBX block. the only reason this argument came up is because i was simply restating what someone else recommended for a specific block and you came in thinking you know it all and had to say that no matter what, a pump with 10feet head and 150gph will beat any pump at 300gph pump because they have poor head ratings. well if you looked around, there are many pumps that can do 300gph with a good amount of heat. many of those pumps would be fine for the rbx block and a rad.

[AngryAlpaca]

Smack him. If that doesn't get through to him, smack him again. Tell him to do some goddamned research on his own. Remember: More flow equals more heat. Flow has vastly diminishing returns. Heat is always equally bad. Smack him a third time for good effect. Generally speaking, a 300GPH pump will have more head than a 150GPH pump. However, since the emergence of the MCP 600, that generalization becomes less and less correct. Joe is generalizing. Generally, that generalization is accurate. Try to do some research beyond picking up generalizations.

[gustav]

im not the one looking for wcing parts. he's the one looking for them. i was just restating what joe said to he and he went friggen ape saying that a 300gph pump has little to no head, and yet i cant find lots of 300gph pumps with plenty of head. if he wants an underpowered pump that gives out 160 or so gph with 10ft + head, then thats fine, but i would think something in the 250-300 range with decent (around 6ft) head would be a better pump.

[AngryAlpaca]

See, now that's just wrong. It's so wrong it's not even funny. Look at the pro/cooling article. Those are 300GPH pumps with a little over 6 feet head. They lose to a 165GPH pump with 11ft head. Hmm... Also, the 165GPH pump puts out WAY less heat. Around a third, or maybe a quarter.