Henry,
As far as I know nobody has ever posted back-to-back dyno readings from the same engine on the same dyno on the same day using a faster-turning fan vs. a slower one.
That is why I have two pulleys, one 130mm and the smaller version. When this engine is run on the engine dyno, the debate will hopefully be resolved. Empirical testing is the essence of the scientific method.
The reason for the double pulley arrangement for later cars was to allow the alternator to be run at a higher RPM than the fan for more electrical output. The fan could not be run at the higher speed for noise purposes. The cup pulleys available for the 964 and 993 run the entire assembly at the lower fan speed at the expense of reduced alternator output, which makes sense considering that race cars generally operate at higher RPM and have fewer current consumers (HVAC, etc.)
LOL comparing me to an Ostrich, this is why it's great having you on the board, have a great day!
