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Unread 03-17-2005, 02:37 PM   #27
Jimbo Mahoney
Cooling Neophyte
 
Join Date: Jan 2005
Location: UK
Posts: 96
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OK, results:

2 x Swiftech MC600 / AQX 50Z's in series.

5/8" on suction side

1/2" on both link between pumps and output of second pump.

Nexxxos XP block only.

@ 12v = 6 lpm

@ 13.8v = 6.6 lpm

This was done using a stopwatch and a 1 litre jug

Noise levels didn't increase, just the pitch.

The PSU I'm using is from Maplin, part XM22 (£20).

I have now modded it with a 2200uF cap, part VH54 (£0.49), immediately before the output (you can just make out the blue cap on the left side connected to the red and black output wires):




I doubt you need to do that, but the oscilloscope output before the mod was quite nasty - it was very noisy and varied by as much as 0.4V in spikes. With the 2200uF cap in place, it was much smoother and only varied by about 0.15V.

If anyone's interested, there are two small pots immediately below and to the right of where I've added the cap, and the leftmost one (labelled RV2 on the board) controls the output voltage. It can be changed from 12.15 V to 15.25 V. I didn't want to test the pumps any higher than 14.4 V and the improvement over 13.8 was minimal.

Hope this is of some use to people.
Jimbo Mahoney is offline   Reply With Quote