Low speed normally means you have a fan inefficiency since at higher speed, speed creates air flow without a fan.blown265 wrote: ↑Sat Jun 25, 2022 5:05 am G'day all.
I have a Davies Craig EWP150 40gal/min electric pump installed in the lower radiator hose, adding flow to the factory mechanical pump, on my personal 1971 street/strip car.
On the subject of cavitation, does this electric pusher pump before the OEM mechanical, raise the rpm cavitation threshold?
For example, if the factory (pressed impeller) mechanical item thrashes the water at 5000rpm, does the added EWP150 electric raise this rpm point appreciably 6000rpm?
The reason I ask, is if the above premise holds true, I was considering raising the mechanical pump speed with a smaller pump pulley for more low rpm flow, and then relying on the electric pump to maintain reasonable system flow at redline. (minimal cavitation) The current cooling is good, but I'd like more safety margin for the occasional worst street situations eg, 110 degf summer days on a slow car cruise, or peak hour traffic jam.
I use the EWP150 thermatically switched on at 185 degf, off at 175, and have an indicator light on the A pillar, showing when the electric pump is running. Interestingly, the majority of the electric pumps' use/need is at low rpm, suggesting the factory mechanical is a poor performer at idle and low rpm.
Thanks
Paulie
Low speed low power production creates coolant temp rise if your ignition point is too late and you end up heating the cylinder more than pushing the piston down.
I'd dump the Davies Craig, OEM wouldn't use them and neither should we.