Sanity test my WC loop please
 

Hi guys.

I've been reading these forums quite a bit after discovering Cathar's 'How much pump is enough, how much is too much' thread.

I'm also in the planning stages for the cooling system for my new computer build. This will be the third time I've watercooled, so I'm not a n00b, but not an expert.

Current plan, after reading this forum:

Res->Laing D4->Laing D4->LRWW (or similar)->Maze4 GPU->Maze4 Nbridge->Silentstar HDD Dual (or similar)->Large car rad (40 x 30cm)->Res.

In summary - a lot of blocks, 2 x D4's in series + large rad, all in series, hopefully taking advantage of the 17ft of head 2 x D4's will provide.

Tubing will be 1/2" ID.

This will be a totally caseless scenario too, with NO 90' bends and minimal tubing runs.

Does it sound realistic, high performance and make sense?

Thanks.

Jimbo

You might have problems running the D4's in series. I remember something about that being an issue. Might want to search on this. I believe BillA had something to say about D4's in series (I think it was the shaft seals?) when the discussion was about the C-System's pumps (and their reliability).

i would change LRWW for storm, and i guess a single D4 would be enough.

Thanks for the heads up Brians256. I've searched for BillA's posts and also for D4 serial, but no joy (well, no joy in the fact I've found nothing, which I suppose could be good? :))

Satanicoo - I'm certain 1 x D4 will be enough, but if 2 D4's provide 17 ft of head, which they should, then (referencing Cathar's article about head / flow / C'/W) 2 x D4's should provide a 1'C drop on the CPU temp, which I'm willing to pay £50 extra for.

Re: Storm. I've heard about these, but cannot find them in the UK. I can find the NexXxos blocks though and I've heard mixed things. I've used the LRWW before, and apart from cracking the lucite :cry: I was very happy with it! :cool: I'll get brass-topped blocks this time round...

Yeah, you have to order them direct from Cathar in Australia whenever he makes up a batch. IIRC he isn't making any more of the copper variety, but is going to be making some silver ones in the next month or so. These will be £50-60 more expensive than the normal ones, and the ProCooling test data should show you how much cooler they will be (can't really check it as at work but should beat the LRWW by more than 1C). Probably well worth it for your application.

Hmm,

Thanks for the info but...

I don't think I would want to order anything from outside the UK TBH. I did it once and got stung TWICE - once by the delivery company for paying my customs charge (an 'Admin' charge of £20) and also by customs. :(

I would much prefer to order the best block available in the UK and a second pump to get the head pressure up. If that's the case, the following are easily available:

(I would be going A64 unless someone suggests otherwise - the Dothan chips from Intel look interesting...)

DTek LRWW
Any Dangerden stuff (RBX, TDX, silver, copper)
NexXxos
Polarflo

The impression I get is the LRWW, RBX and Storm are the best blocks right now (please correct me if I am wrong!), but I would rather not order the Storm outside the UK.

Jimbo

EDIT - are we allowed to discuss UK shops for WCing? I frequent a UK forum where this is strictly forbidden, I'm sure you know which one I mean. Trying not to be elitist, but it tends to be full of n00bs these days. I'm trying to get my info from here and xtremesystems now. Also, is there some sort of rivalry between Xtreme and here? I noticed a few threads about banned IPs and what-not. Just so I don't mention anything I shouldn't in future!

Jimbo,

There's a very long list of w/c suppliers for here that may help you. Note that there's plenty of German shops that will ship to the UK at good prices (i.e. DDC pump is EUR72 inc tax or EUR90 in the 'Pro' mod version).

Regarding your plans, I'm a fan of the incremental approach. why not start with one DDC, see how your temps are and then add a second if you think its required.

Incremental is a good idea.

1 x D4 or 1 x DDC should be ample for pumping the water round the system, but more head may drop temps.

Think I'll go for one at a time then. It'll also spread the fun over a longer period of time :D

I tend to go overkill when planning for things...

Just looked at that link!

Sweet! Thanks!

Do D4's even have a shaft to put seals on? I had thought the rotor was driven by progressive magnetic fields, not a shaft. Here's an
expanded picture at laing.de.
There was quite a discussion of shaft seals with the c-systems pumps. First doubt that anything with shaft seals could last the projected life - and then (a couple of months later) pictures of pumps with seals that actually had failed. And, of course, any centrifugal water pump with a shaft would have its lowest pressure at the center of the rotor - which is where the shaft (and shaft seals) would be - so you'd mostly be sealing against atmospheric pressure, which would be completely wrong for in-series pumps, or at least the second pump in series. C-systems offered an in-series pair and I (at the time) wondered if the second pump had a different shaft seal). Never found out and it doesn't matter now, does it? :)
Sorry for wandering off topic.
I don't know if you've found it (I always have to search a bit when I'm looking for it) but there's a very good interactive waterblock comparison page here at procooling that might help you decide which block is most appropriate for you.

Brian this is an issue with the C-Systems pumps, NOT with the D4's... they are perfectly fine in series, I ran 3 in series for months.

Heh, thanks bobkoure, I couldn't find anything.

nikhsub1 - I did think about your system with its three D4's - how noisy was THAT? I had an early D4 and found it very whiny, were yours the newer 07/04 models?

I'm now torn between the DDC and the D4...

tempted with the DDC though I have to say...

bobkoure - thanks for that link to the interactive graph.

I think I underestimated the Storm G4 :drool:

Sod the expense, I'll be preordering one. Luckily I don't need it until summer at the earliest, so that should be OK.

Thanks, nikhsub1. I couldn't remember. However, I wanted him to check before he tried it. Some pumps simply aren't rated to run in series, so you can't assume.

If he can't find it with searching, I'd try sending an email to swiftech support. They'd be the definitive answer on how well the pumps would work in series.

First two batches of G4s are sold out. Not sure if there will be another - Cathar is often around here so may be able to confirm. If not, there are always the G5s...

Aren't the G5's twice the price though?

Also, rather than starting a new thread.......

Radiators:

Why do people use heatercores? I'm assuming - size and cost (they are cheaper than those rip-off PC-specific radiators and are small enough to do internally mounted case systems?).

Has anyone used a car radiator before? I used one from a Rover Mini before and was very pleased with the temps I was getting.

This time, I have a larger rad (30cm x 40cm core) bought for £10 from Ebay (brand new).

Using my crude calculations, it can do 1527 watts with a 10'C delta T (water / air), 3.8lpm water flow and some reasonable fans. (Source = http://www.overclockers.com/articles778/index05.asp and a simple conversion from the 120.3 to my 30cm x 40cm).

Presumably, with a 5'C delta T, it would dissipate 750 watts, or thereabouts? Also, is heat dissipation linear with airflow, so if I halve the airflow, I get 375 watts?

Thanks for any critique......

HC's are used for two reasons.. Better design, and they are cheaper.. Im not bashing the made for pc rads, but they just cant put the design time in like the HC manufactuers can. Those companies have much larger budgets for R&D (actually their R&D budget is more than the entire budget of the pc rad companies) so they are able to design more effecient heatercores.

And to asnwer your question about heat disapation, no it is not linear. Anything in life or cooling for 99.9% of the time is not linear... That said, I have no idea how much heat it would dissipate with half the airflow.

If you double the airflow, your temp will drop, but the dissipation will still be the same. So it doesn't really make sense to think about it like that. But yes, if you regulate temperature exactly, and can exactly half airflow, you would expect roughly half the dissipation. Realistically though this is only going to apply for relatively small changes in airflow. THere is only so much and so little air you can crame through a rad before the gas dynamics are going to start to have an effect on things (speculation on my part, I've never tried to measure it).

More interesting would be to estimate a C/W curve for your radiator, plug in your dissipation, and try and guess the temp. Unfortunately radiator thickness, flow resistance, fins per inch, and material will all be different then a heatercore, so getting accurate numbers with out doing the measurements your self is nearly impossible.

Sorry there, but nope.
The HeaterCores are designed for something totally different from a watercooling application.
1) HIGH temperature differential
2) High pressure fan - usually a blower, at least in the cars I've taken apart.

Think about it - what temp is the water in your cars cooling loop? heatercores and car radiators are designed for high pressure fans and a high temp differential.

Whereas WC wants a low temp differential (if your water is 20 degrees above ambient, thats *BAD* for watercooling) and low pressure quiet fans.

Totally different design ideologies.

heatercores are a compromise for us watercoolers - they are cheap, readily available, and do a pretty decent job. But they are by no means designed for the task we are using them for.

Here at procooling, we love to split hairs about stuff that in the real world is mostly meaningless :D. I have to agree with Althornin though, heatercores are not intended to cool anything really, their purpose is to get hot and stay hot via the car's coolant for our comfort known as heat (inside the car). They are just a constant heat source and nothing more. The reason (again agreeing with Althornin) they are so common for our app is primarily because they are cheap and are made of copper/brass and come in the right sizes for our needs. They are generally not too restrictive either, their one big drawback is that they are so damn thick.

OK, so why don't people use car radiators? They are just as cheap, if not more so. The only disadvantage I can see is their size and perhaps the 'labour' involved in changing the 1" hose feed to 1/2" barbs. Surely, given their size, they aren't very restrictive either?

Because they're huge and heavy maybe? :p

I'm pretty sure the WAFO radiator Cathar's using started out as a small car radiator.
Here in the states they are pretty much all inconveniently big and heavy. The ones I've seen (but it's been a number of years) are fairly air restrictive, but that might not matter with comparatively low air velocity (lots bigger so lots more parallel air passageways).
Then there's the header tank modifications you mention, and the fact that many modern rads are made of aluminum - or even an aluminum core with plastic header tanks.

OK, I just thought it was common knowledge that they were crap or something!

It seems it's just the mods and size.

I checked on the structure of mine - it's a 1980 (ish) brand new one with plastic tanks and a copper core (so the dealer reckons - it certainly looks brassy / coppery inside)

I previously used a 1970 (ish) Rover Mini radiator which was almost half the size of my new one.

I'm going for performance and silence over aesthetics - I don't think I can be bothered to cram it all into a case, and I have a BIG case (Yeong Yang server cube). I just remember it being a LOT of hassle to get everything plumbed in, so I'm just going to run it on the desk. I hope to upgrade it regularly anyway.

Same problems as heatercores.
Designed for high airflow, highspeed fan, and massive temperature differential. The water coolant in your car is how hot? And the water in your WC loop is how hot? How much air does the car's radiator fan pull in? It's a beast, thats for sure.

Again, different designs because of different applications.

We need a low air resistance (to go with our crappy fans) radiator designed for a low temperature differential and low airflow system.