Recently I had an opportunity to purchase some used Meriah cooling fans that were in great shape. The Meriah cooling fans have been used for many years as an upgrade for the stock Lucas Pantera cooling fans on cars that have upright radiators. The fan motor is about 1.5 inches longer and about 3/16 inch thicker than the stock Pantera fan motor.
The fan assembly has ten blades with an air flow ring molded on the outside edge of the blades. The distance across the fan blades is 12 and 1/4 inches.
I used this 3/4 inch long, threaded hex spacer between the stock fan motor clamp straps to adjust for the larger motor diameter. The spacer was bolted to one strap and I used a bolt on the other strap that threads into other end of the spacer. This arrangement helps keep the strap ends from bending over as it would if you just replaced the stock bolt with a longer one.
View of the driver side Meriah fan installed. The other stock fan can be seen in the background on the driver side. I had to move the fan power cable from in front of the fan motor to the top of the fan motor because the fan motor is longer than the Lucas motor. I used a wire tie around the hex spacer to tie down the power cable. I positioned the fan blade about 1/4 inch away from the radiator core and I didn't have any clearance problems, including the radiator cover that goes between the front of the car and the top of the radiator. My car has a very early 5 row upright Hall radiator that has be re-cored with a denser 4 row core with 20% more tubes than the 5 row.
View of the fan motor from the front of the car. I didn't need to change any of the fan wiring or fan relays because my electrical system has an upgraded wiring and relay system. The fans move a lot more air than the stock fans but I do not have tools to measure the increased air flow.
View of the driver side fan motor.
Job complete with radiator cover in place.
On the left the fan not running - on the right the fan is running
I noticed that the Meriah fans move a lot more air through the radiator than the stock fans. You can feel the hot air moving under the car and into the front wheel wells but most surprising a lot of air moving up through the GT5 hood vents. There has been much debate and discussion about how much if any air moves through the vents ever since the GT5 went into production with the new vents. Most people believe that no air escapes from the vents or very little.
I decide to do a very unscientific test to see the air flow from my vents by taping some paper towel strips to the vents. The air being forced through the radiator seems to hit the flat upper part of the front trunk wall and then comes out the vent and is blown up at a forward angle. There is enough air moving through the vents to bend the paper strips back to the front of the car and hold their ends up 2.5 or more inches over the front part of the vent. It looks like the new fans are moving a lot of air and are creating a high pressure area behind the radiator. The air is escaping at the paths of least resistance including the hood vents.
I'm not sure what happens to the air flow when the car is under way but I've noticed for a number of years that the vents seem to collect a large amount of road dust indicating significant air movement. I doubt if the vents add very much cooling when the total air flow is considered but air does move through the vents.
Placement of the yarn tufts
Inspired by the standing test, I tried a road test at speeds from 0 MPH up to 60 MPH. The yarn was only flat along the vent when the car was stopped. At any speed the yarn bowed up at the vent area and part way back on the hood as if air was coming out of the vent with more pressure than the oncoming air above the hood. The tuft tended to bow up more as the speed was increased to about 1 inch or more above the vent. Again this is all very unscientific and your test results may very.