I've been chatting with Keith at
Zuffenhaus about this mod (he built the engine in the pic above) and he walked me through what needs to be done. He was also willing to let me share this info with fellow Pelicans. In addition I've been looking at the PET catalog comparing part numbers between the 3.2 Carrera/964/965.
In order to pull this off what needs to be done is:
1. Source a 3.2 or earlier fan/alt/ring and machine off the rear mounting boss for the early coil.
2. Source a 3.6 fan backdate shroud from Damon at Series 900 (I believe Keith developed the mold for this part).
3. Source a turbo left heat duct and a 911 right heat duct.
4. Consider sourcing a lower crank pulley that's sized about the same as the 3.2 Carrera stock pulley. I believe the Patrick Motorsports 964/993 single crank pulley is the correct size (smaller than stock diameter 964/993 lower pulley). This is to keep the pulley ratios similar to stock and not overdrive the 3.2 fan.
5. On the 3.6 case machine off the fan strap mount bosses.
6. On the L + R heat ducts reposition the lower mounting tabs to match the 3.6 case.
7. Put it all together!
The net result of doing this mod is:
A. Fan output of ~1500 ltr/sec @ 6000 rpm vs. 1010 ltr/sec @ 6100 rpm.
B. Dual heat outlets that easily attach to heat exchangers.
C. The 911 fan sound (louder than the 964 fan).
D. It looks cool.
E. Additional horsepower is used to drive the 3.2 cooling fan. However some folks say the additional horsepower used for more cooling will actually generate more horsepower overall due to a cooler running engine.
I'm not 100% sure I'm going to do this mod but I can post pictures of what needs to be done. The reason being is I want to see if this mod is reversible. Step #5 above is what's holding me back. I'm going to look to see if there's a way to remount a stock 3.6 fan after performing this mod (this will probably require a different fan strap since the original mounting bosses will be gone).
Stay tuned! Thanks again to Keith at
Zuffenhaus for sharing this info!