Hello all,
Reading the MANY threads regarding the air cooled 911 engines (specifically the 78-83 years), there was one thing that has been bugging me. I am curious to know why Porsche chose to place cooling fins on only the bottom side of the cylinder for the 930? This seems counterintuitive to me since they reduce the cooling area while increasing power output.
Maybe to make up for this loss in cooling efficiency, they increased the flow rate of the fan when compared to the 3.0L?
Porsche fan specs:
3.0L - 1:1.81 drive ratio - 1380 l/s @ 6000 Crank RPM
3.3L - 1:1.68 drive ratio - 1500 l/s @ 6000 Crank RPM
I have searched threads relating to cooling or cylinder head temps, and the only thing that I came across that was a little helpful was this (where I found the fan specs).
http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/489193-porsche-turbo-engine-cooling-issues.html