Weird question but why...
 

Is there a reason that we all run two heater boxes (those that do) when one would certainly do the trick? Is it because running just one would be too Frankensteinish? Looks bad or a PITA to deal with?

I mean unless you live Alaska during the winter would you ever need heater switches wide open?

Maybe just run the passenger side only? IDK

Porsche AG probably set the heater up this way, so as not to have to make any other changes when the steering wheel is on the Right side or the Left side, one less thing to 'make equal'.

It's all about symmetry / balance, and capability. You need to supply heat to both driver and passenger, and, since there are two header systems, you have a natural split. With an air-cooled set up, the factory needed to maximize capacity and capability.

As you are from southern California, you might not realize that MANY PARTS OF THE USA BESIDES ALASKA have cold enough weather to make good use of BOTH heater ducts. And, with a cab, it's actually fun to have the heater going full blast with the top down on cold weather drives (even in summer).

Good point!

I see from your California location that you are not in an arctic zone.
Try to get through a couple of winter weeks of zero degrees with only one side of the heat working.
Yes, Porsche knew what they were doing.

Maybe I just run hot but I had the car on the highway through Vail in the winter with the windows open at speed and had them only open 1/4. More than that and I almost passed out! :)

Knowing German's pretty well (I'm married to one) you are probably right about the balance and symmetry. That was my first thought.

Totally agree but do you use everything on full blast when it's that cold? Do you keep it there when driving? Maybe mine work too well? Just seems like overkill and seems especially redundant in warmer areas I guess.

I ride with the heater boxes wide open and adjust the temp with the fan speed.
Remember, I'm dealing with three forty-plus year-old cars.

Anemic airflow when idling at traffic lights is what comes to mind ... when folks were still using these daily for everyday use, effective heat, defrost etc matters a lot more.

Gotcha!

It was "Dual zone climate control" before Dual zone climate control was cool...

My wife rides with me in the 911 in winter time. At a recent fall tour to Arkansas we awoke to 16 degree weather.

http://forums.pelicanparts.com/uploa...1617906390.JPG
http://forums.pelicanparts.com/uploa...1617906390.JPG

My 85 has a fantastic heater. My wife is typical of many women and likes it warmer than I prefer. She can keep her side cranked up and I can put my side back to just some heat. I have driven in sub zero temperature and believe me you want all the heat in the car you can get. It was the only time in 26 years of ownership I ran the heater at max for more than 10 minutes.

And it does indeed become necessary to have both side working in defrost mode.

Dual zone climate. Two levers, two heater boxes.

“Duel Zone” An undocumented feature far a head of it time -;>)

That's awesome!

That's true! I love the stories! Man, that looks cold! Great pic too

Follow-up and possible hijack - why was the engine compartment blower motor added with the change in style of heat exchangers? Maybe my blower never worked, but I noticed no decrease in performance when I backdated the heat in my SC - still plenty adequate for temps in the low 30s/high 20s.

Hmmm. My ‘76 912E (3.0L) only has one LH lever for heater control between the seats. Wonder if that helped “keep costs down” on this plain little, price leader of a car back in the day?

Backdated heat works really well but it can be a bit low in bumper to bumper traffic so maybe they added the electric fan to even things out. Remember that a lot of people were driving these cars as daily's so they wanted their creature comforts.