MrJLR, what are your temps doing with that PWM controller doing the fan work? It should be pretty close to what the radiator can cope with. Do you have a full shroud and hood seals? Those Hondas are bull like refrigerator doors with all their hood seals and radiator shrouds. regulating the bottom just determines what the temp of the coolant leaving the radiator is. What if you monitored the upper rad hose for engine coolant temp? Engine pulling more is going to tax the cooling system so if your controller sees hotter coolant coming out of the motor, maybe it would be able to better regulate the engines temp?
