Radiator Thoughts

[moes]

Question to think about, why does a big block radiator have 2 different size hoses? The top hose is always smaller in diameter then the bottom hose is. Why are they not the same size? Would it make the fluid go through the radiator at too fast of a speed to cool it? Is this a restriction that engineers did to help cool the fluid coming from the hot motor into the radiator so it would cool it better?

 

[dadsbee]

Small block same top and bottom. Big block a size bigger on the bottom outlet.

 

[R413]

I Don’t know why. They were like that for 20 years and they seem to cool just fine that way. So don’t argue with success.

BB was 1.75” lower 1.5” upper.

The water can only go as fast as the slowest flow in the system.

 

[hangn0ut]

I just don't buy the "goes thru to fast to cool" line. Look at intercoolers and such. They work well and are not slow with the flow.

 

[gkent]

"goes thru to fast to cool"

You may not "buy it" but its a fact! Once the coolant is up to temp you want it moving slow enough to give off the heat. Otherwise it just keeps getting hotter until something finally blows from the pressure.

 

[hangn0ut]

Then why on the highway is the cooling system wide open regardless of temp? Say a hot day, ac on, pulling a load. A restriction would help it run cooler? Not trying to be a bitch,sometimes I overthink things. Like this. Thanks.

 

[dadsbee]

A/C engines actually have less impeller blades on the pump to slow the flow down....

 

[1 Wild R/T]

A/C engines actually have less impeller blades on the pump to slow the flow down....

A/C engines have less impeller blades cause the A/C W/P pulley is half the size of the non A/C W/P pulley so the pump spins twice as fast....

 

[67belvedere/225]

if your car overheats with a 160 thermostat , then you try a 180 or 190 , so the coolant stays in rad longer
Cause just think if its running hotter than 190 , 160 its just stays open and coolant flows never stopping long enough to be cooled. and coolant hold heat longer that water so more water more heat dissipation in rad. I ve had cars like this 68 mustang come in , and no shroud or fan to far or to close to rad making it move less air through the rad .

 

[WileERobby]

Then why on the highway is the cooling system wide open regardless of temp? Say a hot day, ac on, pulling a load. A restriction would help it run cooler? Not trying to be a bitch,sometimes I overthink things. Like this. Thanks.

Huh ? Wide open ? The thermostat is the regulator. Irregardless, as posted earlier, the coolant requires sufficient time to travel through the radiator to dissipate the heat. Going back in the engine at the same temp as it came out is a recipe for disaster. Quick disaster.

 

[mopar jack]

Generally when it comes to pumps the suction side is bigger and the discharge side is smaller.

 

[moes]

it's like when people say remove the thermostat the fluid will move through the radiator quicker and that way it will cool it faster. Not going to work! I always though the the thermostat was a restriction slowing down the fluid so your radiator could cool it down before entering the motor again.

 

[R413]

Some of these ides put down here are a bunch of hogwash. Weather the t-stat is 160 or 195, it’s open just as far at the regulated temp, the flow is the same.

 

[diesel_lv]

Sooooo, there are a whole lot of assumptions going on in some of these posts. Most of this has been covered before by members who actually work in the field of thermal dynamics. Hot Rod magazine, Mopar Muscle etc are definitely not bibles, they sell advertising.

 

[RJRENTON]

You may not "buy it" but its a fact! Once the coolant is up to temp you want it moving slow enough to give off the heat. Otherwise it just keeps getting hotter until something finally blows from the pressure.

ABSOLUTELY INCORRECT......FAST VELOCITY is the secret to heat transfer efficiency. Based on your premise: "you want it (presumably the coolant) slow enough to give off heat" please show us your calculations to support your argument. You will need to show temperature differences of both the liquid side (heat loss) and the air side (heat gain), pressure losses for both the liquid and air streams, total volume being circulated and the specific heat characteristics of the coolant, if not just water. Once you perform the necessary calcs, you will understand the how's and why's of thermodynamics.
BOB RENTON

 

[diesel_lv]

ABSOLUTELY INCORRECT......FAST VELOCITY is the secret to heat transfer efficiency. Based on your premise: "you want it (presumably the coolant) slow enough to give off heat" please show us your calculations to support your argument. You will need to show temperature differences of both the liquid side (heat loss) and the air side (heat gain), pressure losses for both the liquid and air streams, total volume being circulated and the specific heat characteristics of the coolant, if not just water. Once you perform the necessary calcs, you will understand the how's and why's of thermodynamics.
BOB RENTON

Thank you Mr Renton. I was hoping you would join.

 

[diesel_lv]

You may not "buy it" but its a fact! Once the coolant is up to temp you want it moving slow enough to give off the heat. Otherwise it just keeps getting hotter until something finally blows from the pressure.

As Mr Renton said, you want it moving quickly. Example, my jet boat that is turbo charged w 700 hp and considerable load, boats don't coast. I want 1psi of pressure so I don't cavitate, and my water going through the engine quickly. No mater how short a period of time the water is in the engine, it is pulling heat away from it. W a radiator, the trick is a large enough core w enough airflow to cool off the coolant once it has been heated up.

 

[RJRENTON]

I Don’t know why. They were like that for 20 years and they seem to cool just fine that way. So don’t argue with success.

BB was 1.75” lower 1.5” upper.

The water can only go as fast as the slowest flow in the system.

I believe that the coolant exiting at the tangent to the water pump's impeller blades will have the highest velocity pressure which translates to head pressure which translates into PSI or Pounds/Square inch. This developed pressure divides or reduces as the coolant circulates thru the block and heads to the radiator back to the water pump's inlet to begin the journey again. The total system pressure loss can be calculated by measuring the pump's inlet and outlet pressures, with the difference being the system pressure loss and based on that value, total flow in GPM, or Gallons/Minute can be calculated. The variable quantity is the pump's RPM, which when combined with the pump's impeller diameter at a given maximum RPM, will determine the system's capacity, in terms of BTU's being moved. Points to ponder......
BOB RENTON

 

[1 Wild R/T]

As Mr Renton said, you want it moving quickly. Example, my jet boat that is turbo charged w 700 hp and considerable load, boats don't coast. I want 1psi of pressure so I don't cavitate, and my water going through the engine quickly. No mater how short a period of time the water is in the engine, it is pulling heat away from it. W a radiator, the trick is a large enough core w enough airflow to cool off the coolant once it has been heated up.

Sez a man who runs his A/C in his Hotrod when it's 120 degrees outside.... I'm thinking this line of thought is correct...

 

[Nate S]

You may not "buy it" but its a fact! Once the coolant is up to temp you want it moving slow enough to give off the heat. Otherwise it just keeps getting hotter until something finally blows from the pressure.

Actually not correct. The higher flow makes it turbulent instead of laminar, heat transfers better. They don’t put high volume water pumps in for nothing.