Modifying SC era engine fan to later curved bade fan.
 

What is involved in reducing 911 engine fan whine by modifying 911SC era straight bladed fan with later model curved blade fan?

There are past threads showing the conversion but I would never want to mute the fan sound.

Saw this in one of the earlier threads - "The 964 Turbos used the conventional, far more efficient 11/straight blade fan," That is good enough for me, I will stay with the straight blade fans!

The 964 did not have a engine mounted oil cooler. As a result of air not going thru the engine mounted cooler the volume of air moved could be less. The curved fan used on 964 and 993 does not move as much air as earlier fans. Later fan on early car will not move the designed air volume and could cause cooling problems.

john