Heating system on RSR's

kiato4 · 05-27-2008, 06:43 PM

Hi all:

I'm building an IROC replica and have gutted my Porsche entirely (1975 911S, no sunroof). The rollcage is in I am about to get the chassis painted before putting everything back in. Did the RSR's have heat, and if yes, how was it routed? I have noticed that many 1974/75 RSR pictures show some sort of heater arrangement in the trunk, but they also seem to have the heater block off style plates on the engine. I'm still deciding if I should put the stock system back in after paint or weld the holes in the firewall closed now before paint.

Thanks.

TRE Cup · TRE Cup's Garage

RSR's did not have heaters. They did have the fresh air box (in the front trunk) with ducting routed to help defrost the windshield (which was not so good under really wet conditions)

Though it looks cool to clear out all those parts, we don't recommend removing heaters from cars that are street driven.

kiato4 · 05-27-2008, 07:23 PM

Thanks for the help. The car will be used only on the track, but I do want to have some sort of system in there for defrosting. How is this system routed? I assume I can use the stock 1975 blower motor, fresh air box, both front control boxes, and just route them accordingly. It's a bit confusing in my car because it came with AC as well. Thanks again.

kiato4 · 05-27-2008, 07:37 PM

Actually, just looked at a few pictures of RSR's. It seems that it is just the front blower motor and the fresh air box. I assume the two control boxes in the front trunk are for heat and are therefore not needed.

javadog · 05-28-2008, 05:15 AM

The two control boxws you mention are there to allow you to control which outlets the air comes out of; the defroster vents on the dash, or the footwell vents under the dash. If you remove them, you won't be able to direct the air towards your feet. If all you want is defrost, the route a hose from each side of the fresh air blower motor housing to the dash vents.

JR

DW SD · 05-28-2008, 06:32 AM

JR suggested something similar to what I have setup.

I removed the fresh air blending box mounted at the cowl.

I routed air from the rocker panels direct to the defroster ports at the dash. I kept the controls for the heat exchanger heated air behind the e-brake. I cannot heat my feet, but this does keep the window defrosted and generally warm up the cabin.

I have blocked off the incoming air at the cowl itself with a panel behind the bug screen and some home - made gaskets.

Doug