New RBX and GPU with dual Rads, which pump?

[White94Cobra]

Should I go with an Eheim 1250 or a 1260 for the following setup?

2 Gal. custom made res. made from plexiglass with intake at bottom right and return at top left sitting under case
RBX block on P4 2.8 O/C to 3.6
Danger Den Maze4 GPU block ATI 9800 Pro O/C to 430C/730M
BIX radiator (between pump and CPU)
Chevy heatercore (between GPU and Res.)
1/2" ID Tygon tubing

The flow is Res. ->Pump -> BIX -> CPU -> GPU -> HC -> Res.

I currently have the 1250 hooked up, but the return flow the Res. is very low compared to when I had the Maze3 and no GPU block.

Also, DangerDen recommended switching and going GPU first and CPU next to ease running the tubing... with the theory the GPU doesn't add much heat. Is this OK? It would make things much easier.

 

[Jibby]

i would go CPU to GPU and get the 1260.

 

[Graystar]

Eheim 1260?? That's crazy. It's too big, cost too much, and consumes too much power.

As for the order of the blocks, all I know that when I try to run my dual processor is series I get a large temperature difference. So I personally would always go to the CPU first.

If it were my system, the first thing that I would do is to get a couple of "Y" fittings and run the radiators in parallel. That will increase flow through the system, and might even cool better.

Next thing I'd do is add a couple more "Y" fittings to run the CPU and GPU blocks in parallel. Each block will be hit with the cool water, and it will also increase flow through the system.

Adding the fittings is certainly a much cheaper thing to try than buying a 120 dollar pump.

 

[Arkangyl]

I'd go;

1260 > Heatercore > RBX > BIX > GPU > Res

 

[White94Cobra]

I actually already have the 1260 pump sitting here (got it from DangerDen for $89). I can sell my 1250 so the cost isn't that great. I am just wondering if it's worth drilling larger holes in my res. (very difficult the way it was built) and going with the 1260.

I'm thinking of trying the 1260 using the 1/2" fittings on there now to see if it makes much of a diff. Would it hurt the pump any to run with such a restricted flow? I know I won't get full flow from the 1260 with a 1/2" intake but I'm almost afraid that with a 1" intake it will be too much pressure for the system.

I like running the rads. in series. My theory is cool the water before it goes to the system, and cool it afterward before it goes to the res.

Thanks...

 

[Arkangyl]

Ok, with any pump resticting the inlet is going to kill flowrates, someone here did a test and got EXTREMELY better results with the intel as big as possible...

 

[SK8]

WTF, how did u get it for 89.....

 

[iNSiGMA]

Get a Maxijet 1000 - it will do good.

 

[White94Cobra]

SK8 - They had it for $99 and were running a 10% off Christmas special.

 

[johan851]

Yes, the less restriction on the inlet you have, the higher your flow will be. Make sure you have inlet restriction as low as possible - even run submerged if your pump will allow.

The things really killing your flowrate are the GPU block and BIX. Have you considered (not sure if this would work) running the GPU and BIX in parallel and using the RBX as a splitter? Might not cool as well, but it's possible that the lowered restriction would make up for it. Just a thought.

 

[Rokk1972]

Running the RBX as a splitter wouldn't be a good ideal, You may cause uneven back pressure on the RBX outlets that can lead to performance degradation

 

[johan851]

Not to refute your statement, but I'm curious...how would that degrade performance? If you were to have a more even load, say a NB block on one output and a GPU block on the other - would that hurt performance? It would have to be better than running all three in series...

 

[Rokk1972]

Well, the RBX has a center input that allows the water to contact the base of the block directly over the die first. Then it leaves the center of the block by evenly dispersing to each side of the RBX. If you were to use the RBX as a splitter (manifold) you can/would create uneven backpressure on the outlets of the block, causing a uneven evacuation of water away from the center of the RBX. Now will this kill it? Probably not, I just wouldn't recommend doing it. For this reason is why I run all my rigs with a dual loop system. The RBX gets it's own pump and rad, and the rest of the system (gpu - chipset) share a pump and another rad. But I am shooting for higher than average overclocks with the lowest temps that I can get without going to pelts/phase change cooling.

 

[White94Cobra]

Well I modified my res. with a 1" fitting for the 1260. My CPU temps are actually about 1-2C higher, but I can now O/C my GPU to 480 vs. 427 before. So the extra flow really helped the GPU but not the CPU.

I think I may need some more air flow over my rads. My CPU is at 43C idle and 48C load (ambient room temp is 24C). Immediately after starting Prime95 it jumps to 48C but doesn't budge (tested for 1.5 hours so far).

I am currently running my 2.8 at 3.57 rock stable.

 

[White94Cobra]

I added a second fan to my BIX. My idle temps are now 42C and load is 45C after two hours of Prime95. I'm thinking about making some type of shroud since the fans I'm using have a rather large dead spot.

 

[johan851]

A shroud would definitely increase the available cooling area. That would help a bit, and an additional radiator or larger radiator would also result in a pretty big temp drop as well.

 

[White94Cobra]

I'm already running two rads. Do you think three would be necessary?

 

[E-Licious]

I actually already have the 1260 pump sitting here (got it from DangerDen for $89). I can sell my 1250 so the cost isn't that great. I am just wondering if it's worth drilling larger holes in my res. (very difficult the way it was built) and going with the 1260.

I'm thinking of trying the 1260 using the 1/2" fittings on there now to see if it makes much of a diff. Would it hurt the pump any to run with such a restricted flow? I know I won't get full flow from the 1260 with a 1/2" intake but I'm almost afraid that with a 1" intake it will be too much pressure for the system.

I like running the rads. in series. My theory is cool the water before it goes to the system, and cool it afterward before it goes to the res.

Thanks...

You should consider running the rads in parallel. When you have two things in series, the total resistance is greater than either one. When you run two things in parallel, the total resistance is less than the resistance of either one. The exact equations for 2 resistances in an electrical circuit are:

Series: R1 + R2 = Rtotal

Parallel: (R1*R2)/(R1+R2) = Rtotal

Do the math and you'll see that the total resistance is way lower in the parallel case. I'm sure that the equations for a fluid system are equivalent to these. Lowering the total resistance will increase flow rate for the system.

But, I wouldn't advise running anything in parallel with the CPU block. You get more flow in the system, but you get less flow in each individual branch. Think of it this way, if total flow in the system is 1 GPM, you can't have more than 1 GPM in either of the branches, unless one branch has negative flow rate (going the other direction). So, since you want as much water going through the CPU block as possible, I wouldn't put anything in parallel with the CPU block. Some do, but I wouldn't.

Another advantage of running two rads in parallel is that both rads are getting the hottest water in the system. We know that heat dissapation is fastest when the delta T is highest, so you want the hottest water to be going through both rads.

 

[kusojiji]

I'd go 5/8 outlet to 3/4 inch Y (can't find 5/8 inch Y) that reduces to two 1/2 inch outlets (can be bought at marinedepot.com). This will keep volume up and the reduction will increase speed. Use the lowest backpressure insert in the rbx to keep most of the water from going through the maze 4. Increase the two 1/2 legs back to 3/4 inch (Y) and use only the chevette core or use a heatercore that has bigger fittings or two chevette cores, using the 3/4 inch to 1/2 inch Y's. 396 '68 camaro has 3/4 and 5/8 inch fittings. This core is the same size as the caprice core. And finally go back to your res with a big inlet and your 1 inch pump suction.

The BIX has high back pressure as compared to the heatercore.

Mine worked at 22 degrees C room temp, 22 idle, 24.5 load, using a swiftech mcw5000 and dangerden geforce block, 396 camaro heatercore. Pump was a dolphin dp560.

 

[Spanko]

how much bigger is a 1260 compared to a 1250 anyone got pics of the two side by side? And is the 1260 better then a mag3?