Radiator suggestions
I never said 3 x .75" would cool better than 2 x 1.5"
He was saying the flow through the rad was the most important aspect and I disagree. I say that all the variables are important but you will get no heat transfer without surface area so IMHO fin count is the most important variable as that is 100% responsible for the heat transfer, the more fins per inch the more contact area between the tubes and the fins, the more heat can be transfered .
My opinion in descending order.
Radiator size. It has to have enough coolant capacity to cool the horsepower you produce at WOT.
Water pump capacity. If the pump can’t produce enough volume at any given RPM you won’t have the flow to get the heat out of the engine.
Water pump speed. Again, this goes to the all important amount of flow you have at any given RPM. More flow is always better.
Core size. The bigger the core, the more they flow. And coolant flow is what counts.
Thermostat flow. No matter what, a system with zero restriction will produce the best cooling. Period. A thermostat is a necessary evil to control minimum operation temperature. Using a washer type restricter is bad policy because you have to heat the volume of the cooling system to get to temperature. With a correctly sized and timed (temperature rating) thermostat you are only heating the coolant in the engine. That’s why you have a bypass. So the coolant in the engine gets full circulation while the thermostat is closed.
Fin count. You can get by with way fewer fins per inch if everything else is correct. Less fewer fins per inch means less air restriction moving through the core. And air flow through the radiator is as important as coolant flow through the radiator is.
They are all important but how many fins per inch you have is at the bottom of things I worry about.
Again, that’s my opinion formed from building cooling systems that will maintain 160 degree coolant temperatures on 100 plus degree days, and it’s based on my research long before I ever built the first cooling system.
A phone call to Stewart Components, Evans Coolant, Griffin Radiator and any fluid dynamics and/or thermodynamics expert would shorten the learning curve up exponentially.
