2+2GT
10 Year Member
The high flow = improved cooling is what pump manufacturers use to sell pumps. If you want better cooling, a shroud, better fan, and bigger radiator will do it.
Here's the reason--it takes time to transfer the heat of the engine to the coolant, and then transfer that heat to the air via the radiator.
The restriction is required because if you allow the coolant to flow freely, it will not adequately absorb the heat from the engine, nor will it transfer that heat to the air.
How much time does it take for heat to transfer?
It's interesting to me how myths like this survive. I'm sure it's because the cooling system in a car is complicated, so it is difficult to diagnose problems. Even some "experts" believe this myth. It's possible that the water pump may cavitate if it doesn't have enough back pressure to work against, but faster flow will ALWAYS help cooling.
Imagine blowing on a hot spoonful of soup. Blowing slower will cool the soup faster, right? Of course not! So why do people think that water must move slowly in a radiator? In fact, slow laminar flow is bad for heat transfer. Just ask any turbo expert about intercooler design. You want the fluid to tumble so more of the fluid comes in contact with the hot/cold surfaces.
The 289 High Performance and BOSS 302 called for different water pumps than their lower-performance brethren. The difference? The vanes in the pump were curved, which actually pumped the coolant a little slower, but prevented cavitation at high rpm.
Sadly, these pumps are long gone, although until fairly recently Ford Racing sold the special impeller.
I'm not sure what you're getting at with thermal coefficients.but nobody likes cold soup now do they????
you also forget that the thermal co-efficient of air is but ~.025 while water is ~.6. the water needs more time for the heat to transfer when compared to air, and thus it needs to travel slower to act efficiently.
Also remember that a "high flow" pump will only flow as much as the t-stat will let it. it baisically fills it up to that point, and even though its a "high flow" pump, the t-stat still will do its job. However once that t-stat opens all the way up, it'll still restrict it some, but the "high flow" pump will flow better, and yes, improve cooling, once the engine is up to temp, if it gets to cold, the t-stat closes again.
obtw...I'l be laughing my ass of when you blow too hard and "soup" goes all over your hand
which is strange considering that 'k' values are measured in "W/(mK)" so wouldn't a higher k value suggest that it takes MORE energy to transfer the heat ???
Imagine blowing on a hot spoonful of soup. Blowing slower will cool the soup faster, right? Of course not! So why do people think that water must move slowly in a radiator? In fact, slow laminar flow is bad for heat transfer. Just ask any turbo expert about intercooler design. You want the fluid to tumble so more of the fluid comes in contact with the hot/cold surfaces.