As we have stated in past reviews of their products, Danger Den is one of the most respected names in the water cooling arena. While our other reviews have primarily focused on Danger Den’s water blocks, this will be the first time we have taken a look at one of Danger Den’s water pumps. Danger Den has always sold a few different water pumps, including Eheim and Hydor 110V AC powered models, and they now also have some DC powered pumps that can be powered directly by a computer’s power supply along with the other system components.
Two of the obvious benefits of DC-powered pumps are they can be connected to the power supply with a standard four-pin Molex connector so there is no wiring work required and they power up and shut down with the rest of the system without having to deal with additional power switches. I recently contacted the fine folks at Directron and they promptly sent me a Danger Den D4 pump for this review.
On to the DC-powered goodness…The Danger Den D4 comes nicely packaged in a compact, plain white box that carries a Laing product label as these pumps are manufactured by Laing Thermotech, Inc. I realize that many are fond of more elaborate packaging, I suspect that a white box helps keep the retail price down a bit so I am more than willing to settle for such packaging provided that it serves its main function of keeping the parts from being damaged before they arrive on my doorstep. In any event, inside the box, one will find the D4 pump, a small adhesive-backed neoprene pad (which attaches to the metal mounting bracket in order to reduce any vibration noise) and the Laing pump manual.
While the mounting plate on the pump has two holes in it, there are no machine screws or other fasteners included for bolting the pump to the case. The model I received has 1/2″ OD fittings but there is a model available with 3/4″ OD fittings if anyone has plans for a mega-flow, garden-hose tubed, cooling loop.
• Motor design: Electronically commutated spherical motor.
• Voltage Range: 6-24V DC
• Rated Voltage: 12V DC
• Acceptable media: domestic hot water, heating water, Water-/Glycol mixture
• Maximum system pressure: 15 Kpa(1.5bar), 50PSI for pumps with Noryl housing.
• Pump Dimensions (not including mounting bracket): 3.54″ (L) x 3.47″ (W) x 3.54″ (H)
As can be seen from the pump’s housing dimensions in the specifications, this is an extremely compact pump that can be fit in all but the smallest of computer cases. Even after attaching the mounting bracket and adding the neoprene cushion to the mounting plate’s base, the pump is still only about 4.5″ tall at the highest point (the mounting bracket does not increase the width or length of the pump).
The size of the pump is somewhat impressive considering the D4 has a maximum head rating of approximately 11.5 feet and a maximum flow rate of slightly over 370 gallons per hour (1400 liters per hour). In short, it is a very small pump that can produce more than enough pressure and flow for modern water blocks which are fairly restrictive from a water flow standpoint.
Additionally, since the pump runs at 12v and uses a standard Molex connector, it can be attached to a rheobus and the pumps performance can be tuned up or down by varying the voltage to the pump. Before attaching the pump to a rheobus or other voltage controller, you have to make sure it is rated for 18W per channel at minimum. As I have never been able to refuse taking things apart, it’s time to see what makes this pump work.
The D4 is very easy to disassemble. The main components of the pump are held together by a large pump housing screw ring on the front of the pump housing. As the pumps are shipped with the pump housing screw ring loosened, it is a good idea to check it as instructed in the pump’s manual before firing the pump up for even an initial test run.
Once the screw ring is removed, the blue section of the pump (which is the motor and assembly with the rotor/impeller assembly) separates from the pump housing and the mounting bracket. After the motor housing is free from the pump housing, the impeller assembly can be pulled off the motor for cleaning or other inspection. The ease with which the pump can be disassembled is a definite bonus as it makes installing the mounting bracket into the case and routine cleaning a very straight-forward and quick process.
As shown in the pictures of the D4, the inlet and outlet fittings are built into the impeller housing. While this does not allow the fittings to be swapped out for different sized fittings, it prevents any possibility of leaks from threaded fittings like those used on most pumps. Also, if a different size fitting is needed, Danger Den has adapter kits that allow this pump to be used with different tubing sizes.
In order to test this pump I setup a cooling loop with other water cooling components that I would normally use in one of my cooling systems. More specifically, the components in the water cooling loop were as follows:
• Danger Den RBX (the brass topped version with the #4 accelerator nozzle and 1/2″ fittings).
• Danger Den D4 12v pump
• Approximately 3.5 feet of 1/2″ ID Clearflex tubing.
• Weapon 302 Core and Shroud with two San Ace 120mm x 38mm fans to move air through the 302 core (fan model # 109R1212H1011 – approximately 102.4 CFM each at 12v).
Other system components used were an AMD XP2100 overclocked to 2.32ghz and 1.80 core voltage which produces something in the range of a 94 watt heat load (as estimated by OCTool), an EPoX 8RDA+ with all the possible voltage modifications, 512mb (256mb x 2, dual channel) of Buffalo Technology PC3200 (with Winbond BH-5 chips) set at 2-2-2-11 and an ATi 9800 Pro.
Before diving into installation and testing some general information is required regarding pump ratings and actual performance. The most common questions I see in forums related to watercooling pumps are usually something along the lines of “how much flow would this system need?” or “Does this pump have enough flow or too much flow for this cooling loop?” Flow rate is an important factor in selecting a pump and probably the most widely advertised specification for pump marketing but there is much more to a pump than just its rated flow.
First, the flow rates often quoted for pumps are the flow rates at zero feet of head. Basically, the flow rate for the pump when it does not have to fight any type of restriction. This number is often close to worthless when evaluating how a pump will perform in a watercooling loop because almost all modern CPU waterblocks have a good deal of restriction due to jet impingement designs. Additionally, other components like GPU waterblocks, chipset waterblocks, 90 degree fittings and heat exchangers add additional restriction to the cooling loop.
To determine the type of flow a pump will have in a watercooling loop, the flow rating and the maximum head rating have to be checked. The maximum head rating for a pump is important because it is a solid indicator of how much flow the pump will have with different levels of restriction. Some pumps that have really nice looking flow rate numbers turn out to be close to worthless for watercooling systems because they are designed to move a lot of water in an essentially resistance-free environment.
So, once any restriction is added, the flow rate of such pumps can drop down close to nothing. Most quality pump manufacturers will have a performance chart for their pumps that shows the pump’s flow rate across a range of head pressures. The performance chart is a much better indicator of how a pump will perform in a cooling loop than a gallon per hour rating at zero feet of head.
With that in mind, a quick check of the DD4’s performance chart reveals that even at around 8.5 feet of head, the pump is capable of moving around 106 gallons per hour which is more than sufficient for most watercooling loops.
Other factors that should be taken into consideration are the amount of heat the pump will add to the coolant and the amount of noise the pump produces. Depending on the design of the pump and the amount of power it consumes, water cooling pumps can dump some extra heat into the coolant.
While a pump’s wattage rating is usually a fair indicator of how much heat will be transferred into the water, different pump designs can lead to more or less heat than would be expected by the power rating. As a general rule of thumb, if the pump really heats up while operating and the housing on the pump is very warm or hot to the touch, the pump is adding some heat to the coolant.
However, pump-related heat issues are usually more of a fine tuning factor when trying to get the absolute lowest temperatures unless the pump is massively oversized and runs insanely hot. With most of the commonly used watercooling pumps, the heat from the pump will result in less than a 1-2 degree Celsius difference in coolant temperatures.
The amount of noise from a pump is somewhat of a subjective factor but noise can make a pump intolerable regardless of the pump’s performance. While dBA meters can provide a number for the raw volume of pumps, fans, etc., the tone and pitch of the sound is usually what determines whether or not the part is considered loud or annoying. Watercooling pumps can make a variety of annoying sounds such as impeller ticking or clicking, humming, vibrations noises, as well as others. So, how does all of this apply to the DD4?
For my initial testing of the D4, I attempted to simply attach the tubing to the inlet and outlet on the pump, plug in the Molex power connector and start it up. I quickly discovered that this was not a great idea due to the D4’s light weight and small footprint.
With most other pumps I have tested, I could get by with just setting the pump in the bottom of the case and then using the weight of the pump to hold it in place. This is definitely not a good approach for the D4 as it is not nearly as heavy as full-sized AC powered pumps and it would not stay in one place. After taking the initial pictures, I promptly used the base plate as a drilling template and drilled out 2 holes large enough to secure the pump with #8 machine screws.
Once everything was nice and secure, I proceeded to get any air out of the pump by turning it on and off at 5 minute intervals and lightly tapping the sides of the pump to dislodge any air bubbles that were trapped inside the pump. The pump was a bit loud at first but that was apparently the result of air trapped in the pump as it quieted down nicely after I worked the air out of it.
Other than having to bolt it to the case, the installation process was very easy. The inlet and outlet fittings on the pump are ideal for 1/2″ ID tubing as it is not difficult to get the tubing onto the fittings but rim on the fittings provides a solid seal between the tubing and the pump and there were no leakage problems whatsoever.
The Danger Den D4
Yes…I overdid the UV dye again…
During the testing of the pump, I was a little surprised by how well it moved coolant through the loop. The RBX with a #4 nozzle has quite a bit of restriction but the pump happily hammered the coolant through the loop. In order to check the flow a little more closely, I switched from a T-line setup to a loop with a reservoir as I did not have an inline flow meter on hand.
The results with the D4 with a reservoir in the cooling loop were also very good but it is definitely a good idea to use a reservoir with an internal divider plate with this pump or the rate and pressure of the flow from the D4 will turn the reservoir into a swirling bubble and foam generator.
For testing, I wish I would have had another pump in the same class but the only other model in the shop was an original version of the Rainbow Lifeguard Quiet One which is an AC-powered mega-pump. While I briefly considered running them side-by-side, I realized there would be nothing worthwhile from such a test as it would be comparing apples to oranges and the original RLQO is not even available anymore as Pentair Aquatics changed the design shortly after they bought out Rainbow. As such, I ran temperature testing with just the D4 and the other previously mentioned components.
For temperature testing., temperature readings were taken with an Omega 5830 bench thermometer using 700 series thermistors. To obtain idle temperature readings, I stressed the system with Toast for about 30 minutes and then let it set for another 15 minutes before taking the idle reading.
For load temperatures, I cranked up Toast for 2 hours and then recorded the readings from the Omega thermometer. With an ambient temperature of 20 degrees Celsius, the CPU temperatures were 27 degrees Celsius at idle and a very respectable 31 degrees Celsius under load according to the Omega unit. The D4 clearly moves enough water through the loop for the rest of the components to do there job.
Other notes and observations — the D4 ran exceptionally cool during all of the testing. I checked the pump housing several times throughout testing and it was never more than just slightly warm to the touch. As far as noise is concerned, the D4 does make a bit of a humming noise but it is much quieter than most watercooling pumps I have used and the humming could not be detected over the sound of the video card’s cooling fan.
Conclusion
Overall, the Danger Den D4 is an exceptional pump for watercooling systems. It is extremely small and yet powerful. As it is powered by 12v through a standard Molex connector, the pump turns on and off with the rest of the computer and it can be connected to a rheobus to tune its performance provided the rheobus is rated to handle 18w.
The only minor complaint I have is that it does not include mounting screws for attachment to the case but that is easy enough to remedy with a dollar or two and a trip to the hardware store if you do not already have the screws on hand. While some have complained that it is more expensive than some other pumps on the market, it is a good deal less expensive than many pumps I have bought for cooling loops in the past and it is a very well made pump.
Danger Den has yet another solid product with the D4 and I give it a solid 9.5/10 and the OCmodshop Seal of Approval. I would like to thank Directron for making this review possible. As always, they were great to deal with and they are a top notch source for computer gear.
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