We all know roots superchargers can make a great deal of heat, especially when the boost bug bites and we crank up the blower speed. Without the proper cooling system this heat can spell disaster. History proves to us the best way to make reliable power is to keep these charge temps cool. This means our supercharger cooling system needs to be as efficient as possible. The heart of the cooling system is the electric pump that circulates coolant within the system. Each component in the system can be seen as a restriction or a load the pump has to fight against in order to move fluid through the system. We call this head pressure, this pressure combined with the pumps ability will play a major role in the efficiency of the system.
The question on ever ones mind is what pump does the best job against this head pressure? To answer that question the guys at Dedicated Motorsports decided to perform a bench test . A test that eliminates the usual variables in a supercharger system (heat exchanger, hose and fittings, intercooler brick and tank) and focuses on the pumps ability in the 0-10 PSI head pressure range.
The Fight Card:
For the most part this test went exactly as we would have imagined. The higher quality pumps that sport higher amp motors ended up flowing the best against the higher head pressure. Keep in mind all cooling systems have head pressure, especially the systems with multiple heat exchangers, numerous reducers or tight AN fittings. All that restriction is accumulative and the pump will be working against it. We will do another article with a flow/pressure test on some common cooling system circuits.
The DMS vote for the best engine bay coolant pump is the Pierburg 100 this little pump out flows any other pump its size at all pressure ranges and doesn’t give up the fight when the head pressure rises over 6 psi. Our vote for the most well rounded rear mounted or trunk mounted coolant pump is the WP32 EMP pump. This pump does well against head pressure and is easy enough to mount/plumb making it our choice for most trunk tank systems.
Now for the results: