"The demand for better 'air through the radiator' performance as never been stronger, especially with the proliferation of diesel pickups on the road today," said Brent Clark, chief operating officer, Spal USA.  "Our new fans are specially engineered for maximum output at high static pressure."

High static pressure results when a large air mass is forced through a single or multistacked radiator 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 radiator has tightly packed fins and a small core.

A good example of high static pressure is a diesel pickup truck.  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 towing a heavy load or has been modified to produce more horsepower.

Featuring a proprietary new curved-blade design, the AP90 HO Series fans are available in 11-inch, 12-inch, and 16-inch sizes. Throughout 2008, Spal USA will introduce additional HO Series fans.

"What's critical to understand is that our fans hold their airflow rating in very high static pressure," Clark said.  "Zero static, or 'free air' readings do not register high, so don't be fooled by huge cfm claims.  The fan's ability to maintain its performance is the key."

 
Like all SPAL fans, the AP90 models feature rigid, glass-filled nylon blades dynamically balanced internally and externally to minimize vibration.  The fan motors are sealed and individually balanced, and the entire assembly is heat resistant, meaning the fan can be expected to outlive the vehicle in which it is installed.