Alphacool HF D5 Top
The Alphacool HF D5 top comes in both plexi and acetal versions. It’s also the most affordable top out there at $31 for the plexi version. Despite that price it comes in a nice box:
It also comes with two copper stop fittings for the alternative input and output ports:
However the screws that bolt the clamp to the mainbody do not match the usual alphacool copper theme. There is a mounting bracket but nothing to help isolate any pump vibration from the PC case itself.
The plexi top itself looks good when mounted to the floor of a case, however if it were to be mounted vertically the logo would be upside down and presumably hidden behind the pump inlet feed. Through the plexi you can clearly see the 90 degree bends that occur between the primary input/outputs and the secondary less efficient input/output:
The volute looks like the standard cone shape used by most high flow tops:
To test pumps I use a flow meter and a differential manometer and vary restriction by adjusting a brass gate valve. I adjust the gate valve to give different flow points and measure the pressure “gain” across the pump using the differential manometer. To understand how to read these plots check out this guide.
Leaks
Before getting stuck into the data it’s worth mentioning the issues that I had with this particular top. The first test I ran with a D5 Vario and after tightening the screws “tight enough” for my liking I found that the pump was leaking slowly and bypassing the o-ring seal. I proceeded to tighten the screws further (really really tight) which did finally seal the block. However one of the bolt heads started to strip. When I fitted the D5 strong for testing the same thing happened but this time the bolt head stripped completely and I had to drill it out. I wondered why the leaking would occur when the design was so incredibly similar to the EK top (the internals and bolt/clamp pattern seem identical). As far as I can tell the difference is the o-ring. The EK had a thicker o-ring. The EK part was also made of acetal which might also help. For now I can’t recommend the Alphacool because of this leak.
Performance Data
The Alphacool top does at least perform well. Through the region of interest (0.75gpm-1.5gpm) there is a small gain in performance over the standard Laing top regardless of whether you use the optimal ports or the alternative ports. If the top is compared to other tops with a D5 at max we can see that it performs at the top of the pack:
Summary
A well priced high performing high flow top that sadly can’t be recommended as it is let down by a tendency to leak unless you over-torque the clamp bolts.
Where to buy: PPCs
