5. How does radiator core thickness affect cooling?
Be CoolIncreasing core thickness slightly increases cooling capacity. It should be noted that increasing frontal area is a more efficient means of increasing cooling.
Flex-a-liteIn vehicles with the belt-driven fan option, the thickness would not be as much of a factor in cooling as the electric would. Electric fans, when installed, will require a minimal static load, blockage, in front of it. In the event a "multicore" radiator is used, it may cause a reduction in the cfm that the electric fan can pull through the core. Too much static load will reduce the effective cfm to a point where it will not cool the application.
GriffinCfm is too low with a thick core (more than 2.25 inches) and the fan, so you then run the risk of the radiator not cooling properly at idle.
Mattson's The air will have a hard time cooling off the radiator if the radiator is too thick. Some of the old continuous fin-type cores were great for the dirt roads and minimal traffic a long time ago.
U.S. RadiatorAn increase in thickness over a stock application allows for greater fin bond surface and therefore greater temperature drop. When going from a two-row to a four-row, for example, you double the fin bond or heat transfer points. However, the increase isn't a one-to-one because the transfer efficiency of the trailing rows is adversely affected by the increase in air temperature from the previous rows and the decrease in air velocity caused by the increased thickness.
WalkerThe key to all cooling is determined by the prime cooling area. The prime cooling area is the frontal core area and the prime cooling area of the core is the first 1 inch. This is the area where the radiator fin's design and the air management package are critical. Doubling the thickness of a radiator results in only 20 percent more cooling efficiency.
6. How does fin count affect cooling?
Be CoolIncreasing fin count will increase the capacity to reject heat, up to a point. If the fin spacing becomes too close, the airflow can become restricted and may reduce cooling capacity. OE radiators use 18 to 20 fins per inch. Be Cool has proven that its 14-fin-per-inch design is the most efficient for air travel with the least resistance.
Flex-a-liteTheoretically, the more fins per square inch a radiator has, the better it will cool. More fins will provide more surface area to dissipate heat. Reality is that the number of fins and the angle of the fins can affect the ability of the cooling fan to move the air through it.
GriffinSame effect-you can run a thin core with a high fin count, or you can run a thicker core with lower fin count.
Mattson'sThe type of fin and the number of fins per inch determine the efficiency. The type or too many or few fins affect the proper efficiency.
U.S. RadiatorWe've found that core design, and not material, had the greatest effect on temperature drop. While all radiator cores might look the same, they perform vastly different based on tube spacing and fins per inch. Heat transfer points where temperature is actually allowed to leave the radiator are where the fin is bonded to the tube. The more transfer points, the greater the temperature drop. A '60s core, for example, had a 1/2-inch tube spacing (i.e., 1/2-inch fin between the tubes), and by going from a two-row radiator to a four-row core design, we were able to double the heat transfer points, which resulted in a 15 to 20 percent increase in temperature drop without changing the other variables (airflow, coolant flow). In the '80s, the Japanese came out with a core design in response to the need to downsize that has become the standard and was efficient enough to allow the re-introduction of aluminum (a less efficient heat transfer material) at the OE level. By changing the tube spacing to 3/8-inch, a design referred to as High Efficiency in the industry, more tubes or water passages and fin were allowed across the face of a core with a specific width in inches. The design was simple enough but proved to be very efficient in that more heat transfer points created greater temperature drops inlet to outlet.
WalkerFin count (number of fins in a given inch within the core area) affects the number of times a fin-to-tube contact is made. The more fins per inch you have, the better the heat transfer (up to a point). Too high of a fin count will cause an air blockage, limiting the core's cooling performance.
7. Do you recommend mechanical or electric fans?
Be CoolElectric fans are preferred because sufficient airflow is maintained at idling or low ground speeds. Airflow supplied by a mechanical fan changes with engine rpm and can be insufficient at low-engine rpm, and also uses up horsepower.
Flex-a-liteWith most cars and light trucks, the installation of an electric fan is a great choice to free up horsepower and increase fuel mileage. If the vehicle is to be used under "extreme" conditions, such as towing or when using a four-core radiator, the use of the original belt-driven fan may be a better option.