46 replies to this topic

[Captain Mainwaring]

It's interesting, even if we're all agreed it's not worth the effort.

 

I wonder how well matched the pump & fan are, on their common shaft? Does radial vs axial favour one or the other at various rpm? More effort seems to have been put into developing the fan over the years. I'd assume improving the pump's flow is futile unless heat exchanger bit also keeps up?

 

Perhaps the pump is more of the story, you'd think having a substantial mechanical fan  for a side mounted radiator would be an advantage when stationary: compared to a front mounted rad, deprived of the gale from being pushed headlong through the air.

 

 

Anybody ever tried rear mounted rads?

[Ethel]

I can't make my mind up if that's a quip 

 

I imagine a rear rad might not be all that bad. Unless your aerodynamics are prticularly good, the negative pressure differential behind you car will be nearly as much as the positive one infront of it. As long as you can duct enough air to the front side of your rad.... Busses spring to mind as potential examples.

 

From the "where to stick your oil cooler" quandry, I was led to believe that the shape of the heat exchanger wasn't all that critical with moderate airflow. To maintain an efficent temp differential the air needs to be replaced before its temperature goes up, and the more laminar flow you get in a thicker rad core helps to keep the air moving. I do see how frontal area would become all important  as the airspeed reduces.

 

Mass of water temp decrease > mass of air temp increase. Air entering the radiator will have about a thousandth of the density of the water, and the specific heat capacity bumps up the heat volume ratio to something like 1 to 4 million. I'm thinking aloud, rather than stating an opinion, but it suggests there's far more scope on the air side to cause a beneficial effect.