Quote:
Originally Posted by Old H2S
How about spinning the fan faster and bleeding some flow to make a low pressure blower.
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As I have discussed in previous thread, spinning the fan faster does not necessarily generate additional air flow. It's a ducted fan so fan tip speeds are critical to blade cavitation. Generally, Porsche engineers increased the fan speed to compensate for low RPM running with AC. Sitting in traffic with the AC on was cooking the engines.
Those high RPM fans were generally on low RPM street motors.
Porsche even reduced the fan diameter and the crank pulley diameter on race motors to compensate for fan tip harmonics that created a cavitation.