Click for Coverage
Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
  • JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler

Spal High Output Radiator Fan - Tech

Posted in How To on July 1, 2008
Share this
Photographers: Courtesy of Spal Automotive

Cooling is a major isuue with us as we take our 4x4s off-road and crawl around at slow speeds in 100+ degree heat and blast through snow at high RPM for long periods.

SPAL has introduced AP90 High Output (H.O.) Series electric cooling fans to improve airflow in high static pressure situations across the spectrum of diesel engine applications including on- and off-highway heavy-duty vehicles. If these fans work for them, they'll certainly work for us in the 4x4 world.

"The demand for better 'air through the core' performance has never been stronger, especially with the increasing demand for better emissions and fuel economy," said Terry Dolberg, sales and marketing manager, heavy-duty vehicles, SPAL USA. "Our 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 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.

A good example of a high static pressure scenario is a turbo-charged diesel tractor. 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.

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)

"What's critical to understand is that our fans hold their airflow rating in very high static pressure," said Dolberg. "Zero static, or 'free air' readings have little value, 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 high heat resistant, meaning the fan can be expected to outlive the vehicle in which it is installed.

We've used SPAL fans in many of our V8 swap projects and they have never let us down. These fans built for heavy-duty vehicle use should work even better, providing cooling arflow no matter what we're doing with our 4WD vehicles. SPAL USA is located at 1731 SE Oralabor Rd., Ankeny, IA, 50021. Contact SPAL USA at 800.345.0327, fax 800.654.7725 or visit

Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Browse Articles By Vehicle

See Results