I'm in the process of installing a new all-aluminum bar and plate radiator (BC1193) from Champion Cooling in my 1996 Cherokee. It turns out that in 2013, I purchased the Triple Threat Extreme fan set with integrated shrouds from FF Dynamics. I didn't install them at the time because of a number of negative reviews about how electric fans could not match the mechanical/electric factory design for airflow. I put them in attic storage, and decided to look at them again for this new radiator install.
The three shrouds all closely ganged together cover the the radiator core rather exactly. I was not impressed with the nylon push-through tie-downs supplied to mount the shrouds to the radiator, so I made up an aluminum angle custom mount to fix the shrouds as tightly as possible to one another and sealed the shrouds to the core surface with high-temperature silicone edge gasket material. The modified mount holds the fan shrouds tightly to the core body.
I setup a test rig, first mounting the fans firmly to an 18 inch long flat surface, then took a series of air flow rate measurements. I then added the radiator, bolted it to the fan assembly, and repeated the measurements. Then, I added an air conditioner condenser and did then again. In each case, I measured the applied voltage and the current draw for each airflow measurement. I measured the fan rotational speed for each condition with CenTech Photo Tachometer. I measured the airflow with a handheld Mastech MS6252A Digital Anemometer.
The results are:
The peak current surge when the fans are triggered to start is 22.8 amps at 13.96vDC. After this surge, the fans settled to the results cited.
Open air (no radiator) fan. V=13.98vDC, A=13.68 amps, RPM=1890, Airflow ranged from 1830 to 1905 ft./min. Airflow measured both behind and in front of the fans.
With BC1193 installed in front of fans (not in Cherokee).
V=13.75vDC, A=11.60A, RPM=2210, Airflow ranged from 1350 to 1410 ft./min measured at the rear of the fan. Interestingly the Airflow measured in the front of the radiator (at the radiator core surface) was a very uniform 970 ft./min.
With the AC condenser mounted in front of the radiator,
V=13.57vDC, A=11.92A, RPM=1820, Airflow ranged from 1250 to to 1310 ft./min.
The fan blade diameter is 9.25 inches for an area of 67.2 sq. in or 0.47 sq. ft. This says, just taking the cross-sectional area of the fan that under open air conditions, the individual fans flowed 878 CFM. Against the radiator, they flowed 649 CFM and with the AC condenser added, they flowed 601 CFM. These numbers are per fan and indicate that the 3-fan package is pulling 2634, 1947 and 1803 CFM.
Interestingly, the very uniform air flow over the whole core takes into account the contribution of the three shrouds. The core area corresponds to 2.387 sq. ft. and therefore the total air mover by the three fans amounts to 2315 CFM.
As a final note, all three fans are drawing a total of 11.60 amps with fan installed on radiator.For automotive fans mounted against radiators we expect of the order of 100 CFM per amp. By this guideline, the flow with radiator installed should be around 1200CFM, so the fans are moving more air per amp than expected by nearly a factor of two.
These measurements are crude using inexpensive instruments and under far from laboratory conditions, but they clearly show the differences in airflow from free air to radiator mounted. Also these measurements were take at an elevation 6,125 ft. above sea level.
The three shrouds all closely ganged together cover the the radiator core rather exactly. I was not impressed with the nylon push-through tie-downs supplied to mount the shrouds to the radiator, so I made up an aluminum angle custom mount to fix the shrouds as tightly as possible to one another and sealed the shrouds to the core surface with high-temperature silicone edge gasket material. The modified mount holds the fan shrouds tightly to the core body.
I setup a test rig, first mounting the fans firmly to an 18 inch long flat surface, then took a series of air flow rate measurements. I then added the radiator, bolted it to the fan assembly, and repeated the measurements. Then, I added an air conditioner condenser and did then again. In each case, I measured the applied voltage and the current draw for each airflow measurement. I measured the fan rotational speed for each condition with CenTech Photo Tachometer. I measured the airflow with a handheld Mastech MS6252A Digital Anemometer.
The results are:
The peak current surge when the fans are triggered to start is 22.8 amps at 13.96vDC. After this surge, the fans settled to the results cited.
Open air (no radiator) fan. V=13.98vDC, A=13.68 amps, RPM=1890, Airflow ranged from 1830 to 1905 ft./min. Airflow measured both behind and in front of the fans.
With BC1193 installed in front of fans (not in Cherokee).
V=13.75vDC, A=11.60A, RPM=2210, Airflow ranged from 1350 to 1410 ft./min measured at the rear of the fan. Interestingly the Airflow measured in the front of the radiator (at the radiator core surface) was a very uniform 970 ft./min.
With the AC condenser mounted in front of the radiator,
V=13.57vDC, A=11.92A, RPM=1820, Airflow ranged from 1250 to to 1310 ft./min.
The fan blade diameter is 9.25 inches for an area of 67.2 sq. in or 0.47 sq. ft. This says, just taking the cross-sectional area of the fan that under open air conditions, the individual fans flowed 878 CFM. Against the radiator, they flowed 649 CFM and with the AC condenser added, they flowed 601 CFM. These numbers are per fan and indicate that the 3-fan package is pulling 2634, 1947 and 1803 CFM.
Interestingly, the very uniform air flow over the whole core takes into account the contribution of the three shrouds. The core area corresponds to 2.387 sq. ft. and therefore the total air mover by the three fans amounts to 2315 CFM.
As a final note, all three fans are drawing a total of 11.60 amps with fan installed on radiator.For automotive fans mounted against radiators we expect of the order of 100 CFM per amp. By this guideline, the flow with radiator installed should be around 1200CFM, so the fans are moving more air per amp than expected by nearly a factor of two.
These measurements are crude using inexpensive instruments and under far from laboratory conditions, but they clearly show the differences in airflow from free air to radiator mounted. Also these measurements were take at an elevation 6,125 ft. above sea level.