Cheapest pump, highest head pressure?

will_maltby · Jun 22, 2004

Hi,

I've had a feeling for a while now that my eheim 1250 pump with it's pathetic 6'7" head pressure just isn't cutting it in my system that has an rbx waterblock, an innovatek gpu block and a 22" x 17" car radiator. The radiator is pretty restrictive.

So a few questions;

1) Is the eheim 1250 infact good enough in my system?

At the mo the flow isn't too bad, but it aint good. I'd say it's the equivalent of a good tap trickle/stream. It's definitely under 1gpm. There's no way it could fill 8 pint glasses every minute (8 pints=1 gallon). Infact, doing a rough experiment estimating the flow with the house tap, I reckon it does 1 pint every 11 seconds, making the flow very roughly 0.7gpm

2) What pump gives the best price per head pressure ratio?

Forget flowrate, I'm mostly interested in pressure ability since my system is abnormally restrictive. Noise isn't so much a factor either since I always turn my pump off at night when I turn my pc off.

3) Can I expect any real world improvement in overclock or temps?

Any first hand experience or stories of pump upgrades would be great.

Thanks in advance for any help. Even if you can only really answer just 1 or 2 questions then PLEASE do so!

Any input is very much apprediated.

TheGreySpectre · Jun 22, 2004

my danner mag 3 gives i think 9.5 feet head and costed about $40

Korndog · Jun 22, 2004

mag 3 : 10.5ft head ; 350gph
i'd say this pump is best bang/buck
but the mcp600 is more practicle IMO
low 9watt power, small, and similar head to mag3
but its about 30-40 bucks more :-/

i got my mag3 for 45bucks shipped + ~10 bucks for fittings/glue
mcp600 comes good to go for 70-80

sandman001 · Jun 22, 2004

Two via aqua 1300's in series. About 13' of head and 370gph.

Aphex_Tom_9 · Jun 22, 2004

wow, those are some nice specs on that pump and a good price, but there must be a catch or theyd be used all the time, what do they die quickly?

Korndog · Jun 22, 2004

Aphex_Tom_9 said:
wow, those are some nice specs on that pump and a good price, but there must be a catch or theyd be used all the time, what do they die quickly?

the via's?
they are lower quality (i have three of them for fishtank) and they are a little more noisy. In some cases, they'll die quick, in other cases, they last for years. i've personally lost two out of my three. As long as you don't open it and foul around with the insides, you should be fine. unfortuantly, i had to clean the insides cuz my fish poop a lot, and when reassembling, the rubber endcap got torn, that caused the death for both my via's that died...

if u think about it, a mag 3 is kinda close to two vias in serial. it takes less space and cost almost as much. to top it off, danner mag pumps are good quality.

pauldenton · Jun 22, 2004

TheGreySpectre said:
my danner mag 3 gives i think 9.5 feet head and costed about $40

since he's in the UK (230v/50hz) danners are out

@will_maltby:
1. note that gpm as expressed in the watercooling world is in US gallons - a US gallon being 8 US pints, and a US pint only 16 fluid oz rather than 20 in an imperial pint (ie a pint everywhere else in the world)
so 0.7 imperial gallons would be 0.875 US gpm.... so it's not quite as bad as you think.

say we use 3.5 lpm as the flowrate, then looking at the p/q graph for an eheim 1250 would give an estimated resistance at 3.5lpm (for the system as a whole) of about 1.8M.

http://www.ocforums.com/showthread.php?s=&threadid=263209
since resistance increases as the square of flow to get double that you'd need 4 times the resistance (7.2M) -
an iwaki md-30rz at 50hz would deliver this sort of pressure at 7lpm (ebay is your best bet, and shipping from the US probably... price depends how patient/lucky you are)
or a pair of DD-12Vd4 pumps and a suitable power supply to drive them at 16V (and some ear defenders.....) say £150-200

say you shot for 5Lpm then you'd need just over twice the resistance (about 3.7M)

you could get this by slightly overvolting a d4 (at 12V it delivers 5lpm at 3.2M) - 13.8V PSUs are commonly available and that would do the job. say £60+ depending how cheap you can get the psu.

course you could sell the 1250 to recoup some of the cost...

3. in the rads performance - no.
in the rbx's performance - yes but we're not talking more than a degree or so i expect. whether you could get a better o/clock too is a different issue.

there is one other way to try and increase flow - reduce the restriction:
swaping out the innovatec for a less restrictive gpu block would be a good start.....

Guderian · Jun 22, 2004

Two via aqua 1300's in series. About 13' of head and 370gph.

I don't have the physics on hand, but I don't think head stacks.

nikhsub1 · Jun 22, 2004

Guderian said:
I don't have the physics on hand, but I don't think head stacks.

Yes head does theoretically double with 2 like pumps in SERIES. In PARALLEL the max flowrate would double but head would remail that of one pump.

Guderian · Jun 22, 2004

Yes head does theoretically double with 2 like pumps in SERIES.

I guess what I meant to ask is if anyone had any real world proof, AND the physics of that actual situation.

In PARALLEL the max flowrate would double but head would remail that of one pump.

this one too.

nikhsub1 · Jun 22, 2004

Guderian said:
I guess what I meant to ask is if anyone had any real world proof, AND the physics of that actual situation.

this one too.

YES
YES
YES

will_maltby · Jun 25, 2004

pauldenton said:
since he's in the UK (230v/50hz) danners are out

@will_maltby:
1. note that gpm as expressed in the watercooling world is in US gallons - a US gallon being 8 US pints, and a US pint only 16 fluid oz rather than 20 in an imperial pint (ie a pint everywhere else in the world)
so 0.7 imperial gallons would be 0.875 US gpm.... so it's not quite as bad as you think.

say we use 3.5 lpm as the flowrate, then looking at the p/q graph for an eheim 1250 would give an estimated resistance at 3.5lpm (for the system as a whole) of about 1.8M.
http://www.ocforums.com/showthread.php?s=&threadid=263209
since resistance increases as the square of flow to get double that you'd need 4 times the resistance (7.2M) -
an iwaki md-30rz at 50hz would deliver this sort of pressure at 7lpm (ebay is your best bet, and shipping from the US probably... price depends how patient/lucky you are)
or a pair of DD-12Vd4 pumps and a suitable power supply to drive them at 16V (and some ear defenders.....) say £150-200

say you shot for 5Lpm then you'd need just over twice the resistance (about 3.7M)

you could get this by slightly overvolting a d4 (at 12V it delivers 5lpm at 3.2M) - 13.8V PSUs are commonly available and that would do the job. say £60+ depending how cheap you can get the psu.

course you could sell the 1250 to recoup some of the cost...

3. in the rads performance - no.
in the rbx's performance - yes but we're not talking more than a degree or so i expect. whether you could get a better o/clock too is a different issue.

there is one other way to try and increase flow - reduce the restriction:
swaping out the innovatec for a less restrictive gpu block would be a good start.....

Amazing reply! Thanks for all the working out. I think I've followed what you've said. I guess my system is abnormally resistive (thanks to the huge rad) which is perhaps countering the cooling efficiency due to it knocking too hard on the flowrate. I've already reduced the resistance a bit by modding the gpu block with a dremel to add water veins in it.

I've heard good of the iwaki pumps so I think I'll start to have a look round for that particular model you mentioned. I remember reading a review of the RBX somewhere that showed quite substantial increases in performance with higher flowrates, so perhaps it'll make a difference.

The reason I suspect the flowrate is the prob is that the radiator is so much cooler to the touch than the temp reading (ok, so it's the cwappy mobo cpu probe, but at 52°c compared to the cool touch of the rad, it seems a bit off). I've checked the waterblock mounting over and over and have ruled that out now. I think flowrate is my biggest concern...

Again, thanks to everyone for the input.

pauldenton · Jun 25, 2004

will_maltby said:
Amazing reply! Thanks for all the working out. I think I've followed what you've said. I guess my system is abnormally resistive (thanks to the huge rad) which is perhaps countering the cooling efficiency due to it knocking too hard on the flowrate. I've already reduced the resistance a bit by modding the gpu block with a dremel to add water veins in it.

this block? presumably you're not using 8mm tubing with it??
http://www.thecoolingshop.com/product_info.php/cPath/33_56/products_id/657
if it's anything like this cpu block then i reckon that (rather than the rad which should be very little restriction since it looks like a huge single pass setup) is the cause of the restriction...
http://www.overclockers.com/articles915/

what nozzle are you using with your RBX btw?

Cheapest pump, highest head pressure?

will_maltby

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