Dual Chevettes in Series - Some Results

System Specs:

Abit NF7-S
AthlonXP 1700+ (Currently at 11x210 = 2310MHz @ 1.71v)
2x256mb Mushkin PC3200 Level 2 @ 2-2-2-11 w/ 2.8v
PCI Video card at the moment @ 1152x824 and 16bit color...it's rough

Anyway, I recently added another Chevette heatercore to my setup. I had to run in series because of tubing reasons. My H2O system is:

2x Chevette Heatercores w/ a single Panaflo 120x38mm H1A Pulling on each
Danner Mag 3
DTek Spir@l

I did my best to reduce tubing restrictions, so the output of the Mag 3 is through a 3/4" elbow barb (5/8" ID...I don't think that's too much of a problem) through 5/8" ID clearflex to Rad #1, which is intaking ambient air. From there it's 1/2" ID in and out of the Spir@l to Rad #2, which is exhausting air, then 5/8" ID from the output of that radiator to my T-Line, which is also a 3/4" to 1" copper reducer. From there it's 1" ID clearflex through a 1" ID swept copper elbow to the Danner Mag 3's intake. No barbs on that intake, so it's the lowest intake restriction I'm going to get with an inline setup Any comments are appreciated...maybe things like "hey, that 5/8" ID elbow barb is retarded."

Right now my temps as reported by MBM5 with BIOS 21 are 20C ambient and 38C load. That's actually a bit higher than with a single rad, but I'm hoping that at higher voltages I'll see a difference. Here's my main question though. The Panaflos are on a rheobus, and I keep them in silent mode (about 7v). Oddly, putting them both up to 12v doesn't drop my load temps at all. It usually drops the ambient temp by maybe 1C, but load temps stay the same. I'm taking that to mean that my water temps are already as low as they can get, and the only thing keeping me from lower core temps is the waterblock. Does that sound correct?

I know two Chevette cores for a single CPU is overkill, but this is mainly for future expandability - cooling a 9800 Pro and my NB.

I think you may not be seeing better temps as Rad #2 is seeing the air Rad #1 already had go through it, and is slightly warmer.

With the total amount of cooling capacity of your radiators, I guess it could make sense you might not see any decrease at load.

you wont see that much of a perfromance increase cuz the water going to rad #2 has been already cooled by rad #1.. to increase performance you might want to get 2 y connectors and put your rads in parallel.

I had to run in series because of tubing reasons.

Click to expand...

Yeah, I know the air has already been warmed. That's why water goes through the warmer radiator first. I can't really run them in parallel...and I don't know if the results would be significantly better anyway. Think I need to remount the block or something?

"hey, that 5/8" ID elbow barb is retarded."

Click to expand...

Lose the elbow above the pump buddy

I think that perhaps your system simply isn't putting out enough heat for you to notice a difference at the moment, as your processor isn't overvolted too much, and isn't dumping too much heat. A CPU water block that likes decent flow (a White Water maybe?) might signifigantly lower your temperatures in your current loop, with only the one block.

In any case, I think that when you get that GPU block, and Chipset block in there, you'll be really pleased with the overall low water temperaures you should be seeing - that circuit will be able to handle some serious heat

I'm dying to see some pictures of how it turned out (hint, hint )

LoL - I'd love to post pictures, but I don't have a digicam. It's really too bad, because I just painted the inside of the case as well.

Just to clarify - that elbow is on outtake, not intake. You think it really hurts that much? It's awfully convenient...but if you think it'll make a big difference, I'll give it a shot.

If it's convenient in your setup I wouldn't worry about it

However, it probably is restricting flow to an extent - an elbow is a whole lot more restrictive than a straight tube. That aside, it is unlikely it makes any noticeable impact.

could you change it for a swept one like the inlet?

5/8" is pretty large, so I doubt it would hurt flow noticably.

I'd bet the only way you'd see a noticable temp change with dual rads would be if they both see fresh air and not just one.

Right, but fresh air might be harder to do...I suppose I could set the fan on Radiator #1 to push, and filter it for dust. That would also result in positive airflow, which is a good thing. I might just try that. Is push or pull more effecient?

Can't really change it to a swept one. The swept 1" ID one is actually a smooth copper fitting for copper piping and such. The 3/4" elbow barb has to be 1/2" female thread.

Push/pull has been debated to death. I'd prefer pushing unless I could get a dual fan setup working. Just do a search on that.

Interesting. When nikhsub1 went to dual cores, he saw a pretty good performance boost.

http://www.ocforums.com/showthread.php?threadid=219221

Ya, nik got like a 5c decrease I think. I myself am running dual ProCores in series and knocked off about 2.5-3c under load compared to single setup.

Yeah, I remember Nik's results. That's why I'm wondering if I need to remount or something...

Also, Nik's were in parallel. He probably had higher overall flowrates after the change, while mine probably stayed the same - I added one radiator and increased the intake size on the pump - I figure they'll balance each other out.

I'm starting to think I need a waterblock upgrade...I think I might get a White Water from the classifieds.

Tried remounting, using a slightly different approach to spreading the AS3. I used a plastic bag and spread it with my finger. That dropped my temps 1-2C I think, which isn't too bad. Not quite what I had hoped for though.

I also tried flipping the fan around on the radiator that was exhaust, so that it would intake ambient air instead of case air. Didn't change temps any, as far as I can tell.

Anyway, there's not much that I can do that'll change temps, it seems. Sadly, these temps are even warmer than what I achieved with only a single heatercore. I have a Mag 3 too, so another radiator shouldn't hurt flow too much - especially after I reduced intake restriction this time around. I had a elbow barb on the pump's outlet when I used 1 heatercore and now with two, so while it might reduce flow, it was reducing flow in both systems. I'm trying to find a 45 degree elbow barb to help me with that. Any things that I could try would be greatly appreciated at this point - my temps really shouldn't be this high, at least in my mind. Usually reporting 9C-10C above ambient at load using 11x220 = 2420 @ 1.8v.

Edit - that's 19C-20C above ambient at load.