To find out the different flow rates between the two pumps I used a sink full of water with the above mentioned water cooling equipment hooked to each of the pumps and timed how long it took to fill the 10 liter jug with each pump. There was approximately 1 foot of head to the system and 3.5 feet of tubing. The test was done three times with each pump to help ensure accuracy.

Results:

Originally I used tried this with the Black Ice Extreme rad as well as the heater core but found that it made very little difference which of the two radiators I used . In fact it was so small a difference that it could easily be attributed to a minor inaccuracy of the testing procedure I used.

Eheim 1048 = 42- 43 gph

MCP300™ = 59- 60 gph

That’s close to a 50% improvement over the Eheim 1048, which makes the MCP300™ more comparable to the Eheim 1250

With only one water block in place:

MCP300™ = 85 gph