radiator thickness? 2.25 vs 3.0 inches

[rustrocket]

For the same surface area, what difference does thickness make?

 

Also, are there any advantages to a scirocco style?

[desert dog]

Thicker radiator allows more water to flow through and be cooled.

 

However, cooling efficiency drops a little, but not significantly. 3" is about the limit in thickness where you really don't lose much efficiency. The increase in cooling capacity more than makes up for it though.

[rustrocket]

so, the cooling efficiency isn't directly proportional to radiator thickness?

[grumpyvette]

many 3" radiators have 3 layers of coolant passages while many 2.25" only have two layers, the result is that the coolant flows thru the 2.25" radiator aproximately 30% faster, allowing that much less time for the air to absorb and transfer the heat from the coolant

[v8dats]

i would think width

[Pop N Wood]

Surface area and air flow through the radiatior also play a part. Add too many rows and it will restrict the airflow and can actually reduce cooling capacity. Check the JTR site for his notes on 3 (or 4?) row core radiators.

[Michael]

One would think that faster flow of water through the radiator does NOT reduce cooling efficiency – in fact, quite the reverse. The engine/water pump/radiator/plumbing are a closed system. So, faster flow through the radiator means faster flow everywhere in the system (conservation of mass!) unless part of the coolant flow somehow bypasses the radiator. Water that flows quickly through the radiator will also return quickly; it will spend “more cycles per minute†in the radiator, even if each cycle is shorter. I’m sure that going through the heat transfer equations would confirm that assuming radiator fin surface area is kept constant, that faster water flow increases the heat flux from the coolant overall, into the radiator and into the ambient air.

[Pop N Wood]

One would think that faster flow of water through the radiator does NOT reduce cooling efficiency – in fact, quite the reverse. The engine/water pump/radiator/plumbing are a closed system. So, faster flow through the radiator means faster flow everywhere in the system (conservation of mass!) unless part of the coolant flow somehow bypasses the radiator. Water that flows quickly through the radiator will also return quickly; it will spend “more cycles per minute†in the radiator, even if each cycle is shorter. I’m sure that going through the heat transfer equations would confirm that assuming radiator fin surface area is kept constant, that faster water flow increases the heat flux from the coolant overall, into the radiator and into the ambient air.

 

But the mass flow rate through the engine is the same, so I would think the more time the coolant spends in the raditor the more heat you can suck out of it.

 

Of course if you slow the coolant down so much that it transitions from a turbulent to laminar flow....

[grumpyvette]

"But the mass flow rate through the engine is the same, so I would think the more time the coolant spends in the raditor the more heat you can suck out of it."

 

the opposite would also be true,the more time the coolant spends in the engine the more heat you build up in it.

 

look the coolant flow should be regulated with a thermostat, the job of the thermostat is to slow the flow thru the radiator to raise the heat if its below the t-stats rated temp. and allow full flow untill the temp drops below that rateing, this will work correctly only if the combination of radiator surface area and coolant voluum plus the flow can transfer & release that absorbed heat to the air flow thru that radiator FASTER than the engine can add heat to the engine coolant with the t-stat open, since the internal coolant passages in the engine and its coolant voluum are fixed the obvious factors that can be changed are the radiator size,surface area, and air flow rates thru the radiator that carry away the excess heat,and the designed efficiency and the larger the percentage of that coolant in contact with the radiator where it can quickly disipate the heat it absorbed from the engine, the more effective the system can work.

 

since theres usually packaging concerns, and space limitations, the easiest factor to add efficient is both sellecting an effective radiator design and working at increasing air flow thru the radiator and sellecting the radiator with the most surface area to transfer heat to that airflow ijn that given space, remember air is a poor heat conductor and aluminum is a very good conductor of heat, from coolant to air, so adding surface area to the radiator fins tends to help the heat transfer effeciency as it adds both time in contact between air and the fins and surface area, that can aid in that transfer

this is a good place to point out than a far higher percentage of the engine temp control is the result of OIL FLOW thru the engine and the release of heat into the sump and oil cooler than most people realize, you can very easily drop engine temps 20-30 degrees thru the use of a large baffled oil pan,and a large efficient oil cooler anfd pumping 7-9 qts of oil thru the system