High static pressure results when a large air mass is forced through a single or multi-stacked core. As the flowing air is restricted by the density of the core, a pressure differential is created and the cooling fan must work harder to overcome it. High static pressures can also occur when a core has tightly packed fins over a small area.
High airflow rates are required to cool not only the radiator, but also the charge air cooler, A/C condenser and oil coolers. With such demand, static pressure levels can skyrocket, especially when the vehicle is under a heavy load.
"OEMs are increasingly creative in their cooling systems designs, which means we will see a proliferation of remote-mount cores which have been stacked up to this point," said Terry Dolberg, sales and marketing manager, heavy-duty vehicles, Spal USA.
Featuring a proprietary new curved blade design the new AP90 H.O. Series fans are available in 11", 12" and 16" sizes. Throughout 2008, Spal will introduce additional H.O. Series fans.
Fan length, height and width specifications as well as maximum airflow ratings - measured in cubic feet per minute (cfm) - are as follows:
• 11" = 11.7"x11.9"x4.39" (1,604 cfm)
• 12" = 13.0"x13.0"x4.39" (1,870 cfm)
• 16" = 15.7"x15.7"x3.74" (1,953 cfm)
The AP90 models feature rigid, glass-filled nylon blades - balanced internally and externally to minimize vibration. The fan motors are sealed and individually balanced, and the entire assembly is high heat resistant, meaning the fan can be expected to outlive the vehicle in which it is installed.
The fans are warranted against defects in material and workmanship for three years from date of sale.
More info: www.spalusa.com