W. Alex Edmonds

My car is outfitted w the FVD exhaust w no heat. Wouldn't it make sense then to just delete my fan blower and add the heat duct block and fan block off parts? Not even bother w the RS bypass tube?... Is there any other reason to keep the fan blower in there even though it currently is operating just fine at least I think..

https://www.fabspeed.com/porsche-964...off-1989-1994/

r-mm

I believe the engine bay fan provides additional engine cooling in certain circumstances, doesn't it? Also, the air temp sensor may be an input the CCU needs, even without heat?

ToreB

The rear fan has two purposes, (1) push heated air to the cabin and (2) cool the engine. If you have no exhaust heat exchangers you could remove the fan.
However, the Climate Control Unit will shut down the two front blowers if the fan does not operate. To avoid this you have to keep the temp setting at minimum. I guess you already do.
Cheers,
Tore

W. Alex Edmonds

Thank you.. and will the engine run warmer w/o the fan or is it negligible?

wallra

I removed the fan and added a relay to the rear fuel box and my car does not run any warmed and my heater fans in the front work on all speeds. the fan in the rear is just for the heater If you look at the piping you will see their is no way It cools the engine. May be just the heat ex changers.

Ski Porsche

Wallra—I’m thinking of removing the rear fan on my car, but still want heat in the cabin. Do you have instructions and photos of what you did? I understand rear fan removal has no affect on a/c, right?

Foxman

I also removed the rear blower in both my air cooled 911’s, and agree the car does not run any warmer whatsoever while operating. But the rear blower does help when the car is parked in extreme heat, particularly in garages with little to no airflow. You’re right the blower cools the heat exchangers. It also blows the heated air from the engine out through the two spring loaded dump valves under the engine. See Tore’s DIY guide on HVAC details. Nominal cooling perhaps, but enough that Tore strongly urges all of us to retain the rear blower. And Tore certainly knows what he’s talking about.