BillA's MCW5000 Testing
 

Link

Looks like a good performer. ( 0.22 C/W at only ~0.6 mH2O pressure drop. )

It's nice to see a major block maker taking Bill's testing seriously, and forking out for it. Here's hoping that others will follow.

Regarding the pressure drop/flow rate/performance, what pump would easily get it passed the "knee"?

Good job Bill. It appears that your testing is the standard that no one can argue with. Thank you for your analyisis.

With the blocks flow resistance being so low, the flow resistance of the rad will be a major factor. Fitting flow resistance may also be a substantial fraction of flow resistance.

Asking what pump will get the block past the knee is kind of pointless.

Need another cup of coffee before you start posting Ben?

Edit: Just saving you the trouble Bill. :p

Coffee hasn't kicked in yet, despite two cups.

Ok, so let me rephrase: with a standard heatercore (say, a big momma, aka chevette), what pump would one require?

An Eheim1250, MCW5000, the big momma, and no other flow resistances would get you around 0.22 C/W for the block. That is well past the knee.

(Very quick calculations. Plenty of room for error here.)

Ok, what about an Hydor 20?

You tell me Ben. This is simple stuff. (Though somewhat time consuming.)

Ok, to get passed the "knee", the pressure drop across the block should be at least 0.5 m H2O, which would result in a flow rate of at least 7 lpm, at which a "surplus" HC would drop 2 psi, which is about 1.4 meters.

Seeing that 1.9m is roughly 6 feet, at which point the Hydor 20 will do absolutely nothing... it's a no go.

Ben, Since87,
Your knowledge in this equation is very extensive. What article or reference point do you find most helpful for a beginner at the math like myself. Are they all on this forum, or can you make some recommendations for myself and the other readers. Thanks.

I got this one!

The trick is to match what the combination of the block and rad will do, at different flow/pressures, then "overlaying" this new curve with the pump's, to see where the lines cross. (the error is the pressure drop from the tubing, but it should be negligeable, with proper precautions).

BillA's radiator testing
(Use the "Surplus" unit's curve, because although the bigmomma is the same as a chevette core, it has restrictive fittings)

Add the curve to your block.

Then find the pump curve (see pH's sticky)

...and proceed as described.

For conversions, use http://www.convert-me.com

2 psi = ~1.4 mH2O

Oops, that was mercury... correcting...

Starting over... with a lower flow rate of 1 gpm, the block would drop 0.2 meters H2O, and the core would drop 0.5 psi, aka 0.35 meters H20, for a total drop of 0.55 meters H20, or a bit less than 2 feet.

At 1 gpm, the Hydor 20 can do well more than 2 feet, in fact, it can do almost 4.

So I would guess that the resulting flow rate would be in the 5 lpm range, resulting in a C/W of 0.23, which is very good.

Cathar did a good write up of how to calculate this stuff. I believe I saw it at Overclockers and OCAU. I don't know if he ever posted it here.

I'd suggest searching for it, and if you can't find it, PM him.

Edit: Found it: http://forum.oc-forums.com/vb/showth...hreadid=161563