914-6 heating question, I googled! lots of googling! ...bet someone still answered this one! Options

[davebrossi]

Hi All,

One of the long term dreams that has come to be a possibility within the last couple years is the mythical 'heat' that is rumored to spill out of the vents when the red lever is pulled between the seats. With exhaust systems containing heat exchangers now a reality again, I understand the functionality behind the system from the heat exchangers to the vents, but the final piece of the mystery is just how the air is motivated into the heating system.

The original six used the main engine fan and a set of ducts in the shroud to push air into the system, but in my case, the 3.2 shroud appears to be a different design at least in the fan shroud department. It lacks the two vents of the original six, and instead it would appear an aux fan in the engine compartment was responsible for drawing air into the system. I have the wiring for this fan, but before I start chasing after one, I want to make sure the 3.2 relies on that for air into the heat exchangers.

I had an 81 Vanagon that relied on the alternator to perform a similar function as it had a squirrel cage on one side drawing air into the system.

[Steve]

Just put the 914-6 ducts on the 3.2 shroud and your done. I ran factory heat exchangers on my 3.2 until I recently replaced them with mb911's 1 5/8" heat exchangers. They produce good heat almost as good as the factory heat exchangers.
Check out my blog for pictures. The early steel pipes for each side of the shroud are pretty easy to find, since lots of people replace them with block off plates for race cars.
http://www.914world.com/bbs2/index.php?aut...ch&id=12943

[raynekat]

Search on The Bird for heat back date and you'll get all the info you need. The early steel pipes if I'm not wrong are still available new as well.

[mepstein]

A lot of 911 guys remove the auxiliary fan and "backdate' the heat. You will get less heat flow at idle but it cleans up the engine compartment and still provides plenty of heat if you have stock exchangers or the ones Ben / MB911 makes. We backdate the heat on almost all the 911's we build if they have ssi's. Neither my 4 or my 6 conversion have the aux fan and even the 4 will cook me with heat in the winter.

[mepstein]

Search on The Bird for heat back date and you'll get all the info you need. The early steel pipes if I'm not wrong are still available new as well.

Correct. The metal reproductions are not cheap but they are very nice.

[McMark]

Or you could also install the 73 style single outlet fan that goes under the relay board, and just have heat on the driver's side. Should still be sufficient, and is the easiest install -- unless your car is a 70-71-72 with no blower mount.

[jim912928]

you can use the 911 (with 914 fan cover) aux heater blower motor. With this setup I kept all the 3.2l shroud components. The 911 fan cover is too tall to clear the engine lid...just swap the covers and use the 911 motor and you are good to go.