Iwaki RD-20 and RD-30

[unreal]

Theres a big buy happening on Xtremesystems and I was thinking of getting one of these pumps, from the "How much pump is enough? How much is too much?" thread im left unsure about what to do.

My loop contains LRWW G5, AquaXtreme MP-1 and a PA160. Now I read the Rd-20/30's are really quiet so I liked the idea of them, the price I can swallow (ish.. ) but with the PA160 rad do you think the heatdump might be too large to negate the gains that the pump provides.

Oh and theres no space in my case for another rad so this is all I got..

Thanks!

[phide]

Hey, wonderful find! For clarification... the heat generated by the RD-20 is about 28 watts, while the RD-30 puts out about 45 watts (this is strictly motor output, not inline heat dump). In typical Iwaki fashion, some motor heat is expended by the casing (slight for RD series pumps, maybe 4-7%?), so with an RD-20, you're looking at ~24 watts of total heat dump. An MCP655 outputs roughly 24 watts with nearly all of that being inline heat dump.

I think the RD-20 is a more advisable choice even if you have a very effective radiator considering the specifications of the RD-30 and its heat output.

I'm buying one unless I've missed out.

EDIT: According to Stew, "Basically measured that around 83% of the pump's power draw gets passed into the water during in-line use" for an RD-30.

[Long Haired Git]

Wow, thank's for that quote.
Right now for any pump I don't have test results from that french site for, I assume a heat dump into the coolant of between 50% (zero flow) to 70% (max flow). This was based on the normalised average of the pumps that were tested.
Compare this to the MCP350 which when tested at full flow dumped just 53% of its draw, and from other figures I know at zero flow it would drop just 42% assuming linear power-draw to heat-dump vs flow rate.

So, for a Storm G4 and HE120.2 (performs similar with fans @ 7v?) I get the following with 2m of tubing and ignoring any non-standard barbs on a 90W CPU (simulated die by Robotech actually).
All numbers are out of my approximator and thus can be, well, just plain wrong.

MCP350: 3.09 LPM, coolant temp at exit of radiator of 4.48 degrees Celsius above ambient (°Caa), CPU die temp at 17.63°Caa
MCP655 @ 5: 5.78 LPM, coolant temp at exit of radiator of 4.83 °Caa, CPU die temp at 17.11 °Caa
Iwaki 20RT: 6.79 LPM, coolant temp at exit of radiator of 4.65 °Caa, CPU die temp at 16.73°Caa
Iwaki 30RT: 7.97 LPM, coolant temp at exit of radiator of 5.3 °Caa, CPU die temp at 17.2°Caa

Let me know if you need other pumps (RD20 diffs to RT20) and where I can find PQ graph for them.
As per above, MCP pumps are measured heat dump, Iwaki's are assumed to range between 50% and 70% so if you have a reference to a better figure, please provide....

[phide]

Well, I was going to pull the trigger but eventually decided not to. Need to get the UFO before I begin considering another pump. Would have made a fine pump for my planned test rig, but it's currently not justifiable.

Thanks for the data, LHG. I've come to trust your approximator regardless of how little confidence you have in it

[Long Haired Git]

You can see why I am a fan of the MCP350, especially with the inlet mod.

[ricecrispi]

You also need a 24 psu to power the pump i believe.
$300 investment for 1C improvement and its not even that quiet.

I would get a g7 instead for $300.

[unreal]

Originally Posted by ricecrispi

You also need a 24 psu to power the pump i believe.
$300 investment for 1C improvement and its not even that quiet.

I would get a g7 instead for $300.

I have a G5 , and the mp-1 block is restrictive so thats why I was considering powerful pump. Oh and by the way, stew has an rd-30 I believe - and from what I read he runs it at 18v which is a good compromise between heat + power.

Also when undervolted the heat dump into water at 18v is closer between the to, and the rd-30 has a clear power gain making this one my preference - however as others have pointed out, $300 is alot for a pump! I currently use a 50Z (MCP600) which has a very low dump - and I know the PA160 cant take the heatdump like a 120.3 so this is why I was thinking about not changing.

However if you think the rd-30 dump at 18v is about the same as a MCP655 then the output it has is phenominal!

Decisions decisions...

[phide]

Originally Posted by ricecrispi

I would get a g7 instead for $300.

You can't get a G7. It can't be done.

Making a G7, though? That would be feasible

[ricecrispi]

Originally Posted by unreal

I have a G5 , and the mp-1 block is restrictive so thats why I was considering powerful pump. Oh and by the way, stew has an rd-30 I believe - and from what I read he runs it at 18v which is a good compromise between heat + power.

Also when undervolted the heat dump into water at 18v is closer between the to, and the rd-30 has a clear power gain making this one my preference - however as others have pointed out, $300 is alot for a pump! I currently use a 50Z (MCP600) which has a very low dump - and I know the PA160 cant take the heatdump like a 120.3 so this is why I was thinking about not changing.

However if you think the rd-30 dump at 18v is about the same as a MCP655 then the output it has is phenominal!

Decisions decisions...

Let me help
2 ddc with dual plexitop from europe.
*similar performance
*dual package is still smaller than iwaki RD
*doesn't require additional psu.
*Cheaper
*you get two pumps instead of one big one