Iwaki or Little Giant

I was podering whether the Iwaki MD-55 is better than the Little Giant 3-mdq-sc in terms of water cooling. Price is not and Issue.

Those are both powerful pumps. Make sure they fit and the noise level wont be an issue. Looking at the manufacturers claimed specs for them both, the MD-55 has a lot more power but either of them are more powerful than more frequently used pumps that yield satisfactory performance. If you are dead set on getting one of them, go with the one that is less expensive since both are overkill in terms of capacity. Perhaps some people who actually have one of them will chime in.

Hoot

If money isn't an issue then definitly go with the iwaki (I have an MD-20RZ)

though I agree that the MD-55 is overkill, an MD-30RZ is more then sufficient.

If price isn't an issue then try to find yourself a Custom Sealife Velocity T1 pump. This is the high-pressure version of the more famous Velocity T2 Titanium pump. This pump has two claims to fame...top quality, and no noise.

I just got a Velocity T2 (used, otherwise I'd have a T1.) The amount of water this pump moves is huge, 650 gph at 3' of head. Yet, when it's running you have to touch it to know that it is on.

The T1 version of this pump has the advantage of higher pressure...120 gph at 24' of head. It also has less flow, which is actually good for our WC systems.

Here's the website for custom sealife.
http://www.customsealife.com

Here's a place that sells the Velocity at a good price.
http://www.seaquestmarine.com/cgi-bin/shopper.cgi?KEYWORDS=csl_vt&SEARCH=search

One more thing. You don't really need a titanium pump for watercooling. There is a stainless steel version that cost less (model S1.) I would try to have SeaQuest order it.

My personal recommendation, being an owner of an Iwaki MD30-RZ, is to go with the Iwaki MD20-RZ at most.

Why? The MD30-RZ will add a LOT of heat to your system, and the MD55 will add an extraordinary amount. The amount of heat that they add will far overwhelm any benefit that you will see from the increased flow rates that such pumps offer.

The heat comes not just from the pump's motor, but from the frictional resistances caused by such powerful pumps pushing the water through such constrained equipment as is commonly found in computer water-cooling.

An MD55 will has a rated motor output of 90W, and you can bet that almost all of that energy will end up in your water as heat. 90W is as much as an extremely overclocked/overvolted CPU will put out under full load (many on-line CPU heat calculators will tout figures more like 120-130W - but they lie - 90W is closer to the truth).

If you're using a radiator, that pretty much means that unless you're using something the size of a car radiator, that your water is going to be considerably warmer.

For example, an MD20-RZ will give you flow rates between 8-12lpm depending on your equipment. An MD30-RZ will get you between 10-15lpm. If you look at BillA's data, the extra 25% flow rate gain at these levels buys you at most maybe 0.5C better water-block performance, so unless your radiator can keep the 90W heat output of the MD30 down to less than a 0.5C rise in water temperatures, you will lose. The MD55 will probably buy you lower flow rates than an MD30-RZ, and dump more heat into your water as well. Poor choice.

My advice is that you'll see better results with an MD15-R if you live in the USA (60Hz electricity), or an MD20-RZ if you live in a 50Hz electricity country.

When I said price is not and issue means that I can get both for cheap. It was bad on my part because it doesn't sound like that

would you say that I could get better performance if I went with The LT700 from logiccooling.com?

FWIW...

I have a Little Giant 2-MDQ-SC. It's going to need a custom mount, because it can vibrate enough to make your case rattle, and it's going to need special venting, because although the impeller is completely isolated, the motor's fan spews out hot air.

But I picked it up for $40, new, at a fair

I know someone that uses a 3-MDQ-SC, and he complains about noise and heat too. The noise is the 60 Hz "hum" that we're all so familiar with, but I don't know if it's any louder than the #2.

Propped up, my pump is perfectly quiet.

How much net advantage would these pumps have over regular eheims and danners?


not to get off topic Bigben2k... but 2743MHZ???!! What vcore? Ordinary H2O cooling?

cV said:

How much net advantage would these pumps have over regular eheims and danners?


not to get off topic Bigben2k... but 2743MHZ???!! What vcore? Ordinary H2O cooling?

Click to expand...

I'm starting to seriously think that the Eheim 1250 is pretty much as good as it gets. The Iwaki MD-15R is another very good alternative.

As I stated above, once you start going for more powerful pumps, then pump heat, both motor and frictional, starts to overwhelm any benefit otherwise seen by the higher flow rates that these pumps can push. As a rule of thumb, I believe that for computer water cooling that one should avoid pumps that draw more than 50W of power, and that a 20-30W pump with the highest head in that rough power range, is about as good as it gets. I have yet to see any real-world temperature benefit from going with a more powerful pump than an Eheim 1250 or equivalent.

Also off topic, this is all I could manage from my XP2100+ with water-cooling

Cathar said:

I'm starting to seriously think that the Eheim 1250 is pretty much as good as it gets. The Iwaki MD-15R is another very good alternative.

As I stated above, once you start going for more powerful pumps, then pump heat, both motor and frictional, starts to overwhelm any benefit otherwise seen by the higher flow rates that these pumps can push. As a rule of thumb, I believe that for computer water cooling that one should avoid pumps that draw more than 50W of power, and that a 20-30W pump with the highest head in that rough power range, is about as good as it gets. I have yet to see any real-world temperature benefit from going with a more powerful pump than an Eheim 1250 or equivalent.

Click to expand...

I agree. That's why I'm so interested in the March 893-07 pump. It provides 10.5 ft. of head at only 11 watts. And since it's a DC pump, it can be powered by the PSU. Problem is I can't get it for less than 165 US dollars.

http://www.marchpump.com/documents/Series 893 Parts Sheet.pdf

Graystar said:

I agree. That's why I'm so interested in the March 893-07 pump. It provides 10.5 ft. of head at only 11 watts. And since it's a DC pump, it can be powered by the PSU. Problem is I can't get it for less than 165 US dollars.

http://www.marchpump.com/documents/Series 893 Parts Sheet.pdf

Click to expand...

That pump has extremely impressive characteristics. I doubt that one could really do much better for computer water cooling use. It offers pretty much exactly what one would want. Low power, moderate flow rate, and good pressure (for its power consumption). If someone could offer those pumps for around $60 each, then that would have to be perhaps the most ideal pump that one could use for computer water cooling.

cV said:

How much net advantage would these pumps have over regular eheims and danners?


not to get off topic Bigben2k... but 2743MHZ???!! What vcore? Ordinary H2O cooling?

Click to expand...

As everyone stated, the advantage is pressure. A lot of pumps are rated for a fair amount of flow, but in a PC cooling loop, flow is not anywhere near as important as pressure (aka head).

Here's the article I mentionned.

As you can see, we don't achieve anywhere near the flow rating of most pumps.

It's interesting to note that for the sake of energy efficiency, we're all WAY off!

I posted some info about this here, including how to figure out how to choose a pump, and where one stands, with their pumps. [scroll to the bottom of that page. Ignore the rest of that ProCooling thread]


As for my CPU, unfortunately it's a target: it isn't built yet.

I was just making a spread sheet of some pump specs and could only find the Iwaki Heat specs in Hp so I found the conversion to be HP*746 and got the MD 20 Series to put out only 19W, previously I had read that it was 53w, which is right?

gulp35 said:

I was just making a spread sheet of some pump specs and could only find the Iwaki Heat specs in Hp so I found the conversion to be HP*746 and got the MD 20 Series to put out only 19W, previously I had read that it was 53w, which is right?

Click to expand...

53W. My MD-15R puts out 31W and has a 3.4M head.

Some info about Iwaki MD15/20/30 pumps which I scanned in a while back and you can view here:

http://www.employees.org/~slf/images/md1.gif

There's a difference between motor input and motor output, just to complicate matters. When yousee an Iwaki pump referred to in HP, it's talking about the pump's output, however the motor may be drawing more energy than that. 1 HP = ~750W.

An MD-15R has a motor output of 10W, for both the 50/60Hz models, but draws 26/31W

An MD-20RZ has a motor output of 20/20W, but draws 40/50W (40 for 50Hz power, 50 for 60Hz power)

An MD-30RZ has a motor output of 45/45W, but draws 70/90W.

So niksub1's MD-15R is providing 10W of motive energy into the water, but the pump motor itself is drawing 31W as he says. The extra 21W gets dumped through the case body and into the air as heat, hence why the Iwaki pumps get rather warm/hot to the touch.

Thanks for all the great info, If anyone is interested in my source it is Ebay if you havn't already found out. Since I don't have the patience to wait for a MD 20x pump to come along I think I am going to go with pumps in serial.

I found a good article Here
http://www.unesco.org.uy/phi/libros/hidromecanica/Res14.htm
and at the bottom you can download his file that has equations for calculating the pressure for pumps running in serial and parallel.

i have the iwaki md-15rt . It's a very nice pump and quiet. It can be quite warm--but it's not that hot tho the outer casing of the pump.