Owners with backdated exhausts - how's your heating?

09-09-2003, 09:00 AM

I've finally had my heating system connected with the new backdated exhaust.

Apart from the ugly SC style hoses in the engine compartment I'm dissapointed by heating output. I need to select 5 and up to get any heat at all!? With the stock exhaust I never exceeded step 3!!! With the new exhaust even at max setting it still feels weak and insufficient. And autumn is closing in on us poor danes!

What are people's experiences regarding this??? Please comment.

arcsine · 09-09-2003, 09:07 AM

I have a backdated heater and a set of SSI's. I cannot take much more than a few minutes of full heat as I feel I may spontaneously combust. Downright nuclear.

AirCooledExcellence · AirCooledExcellence's Garage

Yeah my SC with SSI's is the same as Gary's, number 3 is as much as I can stand!!

Cheers

09-09-2003, 09:17 AM

Ok something must be wrong then.

I always thought backdated systems produced as much heat as the stock system which indeed also seem to be the case with you guys. Something must be wrong on mine then? It sure lacks the "baking power" of the stock system that's for sure. Confusing...

arcsine · 09-09-2003, 09:22 AM

FWIW, the "heat capacity" of my system jumped significantly with the SSI's. Unfortunately, I have no help I can offer with your Carerra. Good luck.

09-09-2003, 09:29 AM

Well I did notice one thing that made me wonder. Usually the control box makes a whirring noise when I adjust the setting and often a significant "blower" sound could be heard from the ventilation system. Today when I checked I could hear none of those sounds or at least they were much less apparent.

ruf-porsche · ruf-porsche's Garage

I had a backdated or original heating system in my old 74 911 and it never got warm, with the 82 SC Targa there is plenty of heat compare to the 74. I think that electric blower does add quite a bit of extra heat into the cabin.

Richard C2S · 09-09-2003, 10:47 AM

Does the heating system in an SC have to be modified in any way to work properly if I install the SSIs?

PeterSW · 11:14 AM

I think the reason you can no longer hear any blower sounds is that your footwell blowers get their power or are activated by the engine bay heater fan - which I assume is now no longer there. I believe this can be got round but I know not how - I read an old post somewhere when searching for info on engine blowers

arcsine · 09-09-2003, 11:17 AM

Quote:

Does the heating system in an SC have to be modified in any way to work properly if I install the SSIs?

Nope.

The in- and out-lets for the SSI's are the same as the stock HE's. If you rip out the heater blower and backdated the engine tin, you loose heat at idle. But, the engine cooling fan takes over at anything over idle so it works out in the end.

Milu · 09-09-2003, 12:33 PM

No difference with mine.

Superman · 09-09-2003, 12:40 PM

You mentioned that you have SC plumbing. I have backdated my SC and there is no remnant of the old SC plumbing. Out went that plastic accordion hose. Out went the ugly hose crossing over the top of the fan housing. Out went the blower.

The air inlet to the early heat exchangers is at a different angle, and it was just a little challenging to connect (engine tin needs to be changed or modified). Heat at idle was probably better with the old system, but who needs idle heat? Who idles?

Like Nostatic once said, I can bake a chicken in this heating system. Burns my leg if I leave it on. Jim's Sauna.

Formerly Steve Wilkinson · 09-09-2003, 01:09 PM

Mikkel, I have SSIs on the '83 and the heat seems fine. I installed footwell blowers on each side, activated by a switch on the center console, and because I entirely removed all of the SC stuff--hoses and blower--my source of "pressurized" air is a single outlet on the right rear of the fan shroud, leading into 2.5" SCAT aircraft hose, to a tee, one hose going down to the right heat exchanger inlet and the other across the back of the engine compartment, inder the hood latch, and to the left-side inlet. the left rear of the fan shroud, just ahead of the distributor, is blanked off.

Stephan

ruf-porsche · ruf-porsche's Garage

Quote:

Originally posted by Superman
Heat at idle was probably better with the old system, but who needs idle heat? Who idles?

Who idles? Well some of my co-worker would say that I'm probably one of those idle workers that spend too much time on the net on the Pelican Bulletin Board.

People who store their cars during the winter, but start them occassionally just so everything doesn't rust out and the seals doesn't dry out. We are the people that idles.

arcsine · 09-09-2003, 01:49 PM

But do you need heat in the cabin while you are keeping the car from rusting and drying out?

Gunter · Gunter's Garage

Superman beat me to it: Blower gone, hoses gone, modified sheet metal work on big fan (See Tech Articles) Full heat will fry an egg in 4 minutes or will give you athletes-foot on a 3 hour drive. Even any of those good-for-nothing cats, who normally want to lay right on the heater, can only stand it 1 minute longer than an egg. Mikkel: Have a Tuborg and re-check your connections. Are you saying that you now have SSI heater boxes ??? With blower??? Tell us more about your exact set-up.

carreradpt · carreradpt's Garage

Mikkel, I am looking to do the same with mine (an 85) though I do not have SSI's. You have a Carrera right? VenetianBlau 87 has done this and told me that in order to get the footwell blowers to work you have to bridge the 2 pin connector left in the engine compartment that hooks to the aux motor. I think that might help with your heat woes. I am interested to know if that works.

89911 · 09-10-2003, 07:52 AM

The heating is not a problem. The low volume in output while at idle and at the increased output at high rpm is the biggest inconvienence. The 2 pictures show my car with backdated heating and SSI's. The other is a 72T that shows the correct sheetmetal to do the change.

rfix'n · 09-10-2003, 09:26 AM

I don't have SSI's but do have similar B&B's, no blower fan in the engine compartment and no ability to bring an egg above its refrigerated temp. I'm interested in the footwell blowers comment. Can someone confirm that the wiring for these are routed through the rear 14 pin connector? I think pins 2,7,13 are all related to the engine compartment heater blower. If two of these are bridged will the footwell blowers always be on?

Superman · 09-10-2003, 09:32 AM

Rob, regardless of whether you have the early system or the one with the blower, heat should be excellent if everything is there and working properly. In fact, the blower does not need to work, and you'll still get plenty of heat. Adding footwell blowers to a system that is not making heat is just going to give you a higher volume of the same cool air.

Oh, and your ball joint tool is STILL on my work bench. If you send me your address, I'll send you the tool.