Possible Heat Delete - Pros and Cons?

[Nick Triesch]

Well, the thing is you will sell your car. We all will. Your car will be worth more with the stuff in it that came with your car. Folks want heat.

[Helix8]

Originally Posted by 3literpwr

Anyone have the part numbers needed for this?

Have a look at these two part #'s may be a start for you -
911-106-322-01-PH
930-106-321-01-V2-PH

[Canada Kev]

Originally Posted by javadog

What you don't get is his system is nothing like yours. He doesn't need to lose heat in the cabin with this arrangement. Fresh air, crack a window...

JR

Hmmm... First, you don't really know what the HVAC system is like in my car. It's immaterial what I have, but lets assume that you expect it to be that of any other Carrera. In that situation, it would certainly be different than the OP's and your average short wheel base car, to be sure. And I am also making assumptions in that his is like that of a 1968 912.

If he elects to run a couple of SCAT hoses from the rockers to the windshield vents, great. More power to him. And, yes, he won't actually lose heat, but it will all be directed only at the windshield instead of having the ability to have it at the footwell vents and/or at the windshield.

He will also lose the ability to have fresh air at the vents. Sure he could open the window, but perhaps there's a crazy herd of June bugs or bees or something else he's driving through that he doesn't want inside the car. Having functioning fresh air is kind of a nice thing to have from time to time.

I don't know, but it seems like a lot of trouble to go through to (in my opinion) lose some of the functionality and flexibility of the factory system for no appreciable gains that I can see.

But that's not the OP's problem, it's mine. I just don't get the motivation behind it, so I guess I'll just close my word hole and watch.

[javadog]

Originally Posted by Canada Kev

Hmmm... First, you don't really know what the HVAC system is like in my car. It's immaterial what I have, but lets assume that you expect it to be that of any other Carrera.

Well, you might be surprised. Have a look at how the heater works on a SWB car.

JR

[kach22i]

For defrost I've read that some track car used a 12v blow-dryer from an RV, he removed the fresh air blower duct-work and motor while he was at it.

Another solution I saw in this forum was an item from a UK website, I believe it was a compact marine duct/fan/motor and heating element, tiny output and power draw but just enough to defog. You might want to search West Marine or something.

I bookmarked the UK website a while back, will post it later when I have more time, should be an ebay or Amazon procured item as well.

Try a search here:
Porsche Autocross and Track Racing - Pelican Parts Technical BBS

[carwash]

I guess I just assumed that the stock system is insanely complicated and inefficient but maybe that's not the case. Perhaps I keep the system and reinstall with all new parts. I need to do more research on what parts I will need to make it work perfectly.

[NYNick]

Originally Posted by carwash

I guess I just assumed that the stock system is insanely complicated and inefficient but maybe that's not the case. Perhaps I keep the system and reinstall with all new parts. I need to do more research on what parts I will need to make it work perfectly.

...and there it is!

[Daves911L]

Actually it is extremely simple in SWB cars. A lever to open a valve that lets fresh air in at the base of the the windshield. A single lever to open 2 valves to let heat flow from the heat exchangers to the body ducts. Two slides to let warm air go to your feet or up to the dash. Regulation and mixing is achieved by adjusting two levers and the two slides. It all works pretty well, in my humble opinion, and our '68 has been a daily driver, and taken on quite a few ski trips over the years. 912 and 911 are identical, except for the heat exchangers themselves. All of the body-mounted components are the same (oops, almost forgot, 912 has an extra pull wire in it to operate the flappers). If you already have a 911 engine on your 912, then you have a 911 heat system.

Clean and repair your heat valves. Make sure all the hoses are fresh (paper/foil in engine comp, vinyl between heat exchanger and valve). Adjust the cables correctly. replace the slide covers if damaged. Buy a nice set of SSI heat exchangers (expensive, but worth it), and you will be set for life.

The few pounds you would save by getting rid of the heat system are already offset hundreds of times over by already having a SWB car compared to all all these later cars.

Good luck,
DG

[carwash]

Thx for the push guys. Heat is staying.

Will need to trouble shoot while disassembling, as currently no heat comes out of the defrost window ducts. Air yes, controlled by the knob lever I pictured, but it just controls amount of air, it's always the same temperature.

[javadog]

^^^ Great advice.

It's why I told him yesterday that he needs to read his owner's manual and look at some parts diagrams to understand what he has. I'd wager that most of the threads he's read here on Pelican, that seem to have confused him, have to do with the systems in the long wheelbase cars, which are completely different from systems in the SWB cars from the heater tubes in the rockers forward. It doesn't help that 90% of the replies to his query are from people that have LWB cars and give advice based on how their systems work.

A basic SWB heater/ventilation system is already about as simple as it gets.

JR

[carwash]

Thanks for the advice guys. It is much appreciated. Thx for dealing with me while I learn.

[javadog]

Originally Posted by carwash

Thx for the push guys. Heat is staying.

Will need to trouble shoot while disassembling, as currently no heat comes out of the defrost window ducts. Air yes, controlled by the knob lever I pictured, but it just controls amount of air, it's always the same temperature.

Start with looking at the tubes that come out of the front of the rockers on each side and route the air through the dash. If you follow the path from there to the dash outlets, the problem ought to be easy to spot.

The dash lever controls the fresh air.

JR

[911tracker85]

Ferrino,
my plan is similar to your set up, and it looks great.

but I am thinking of keeping the two way flappers so I can direct heat to windshield or feet. but remove all the other fresh air crap and already pulled all the AC.

saw on another 930 thread a guy who installed NASA ducts on his hood to push fresh air into the cabin.

once you start hacking lots of cool ways to skin this cat.

Mike,
I know part of your thought is about headers without heat exchangers. I have see 2" alum HVAC ducting run (stuffed) between the headers and the heads to pick up heat.

when I get to that point and have the $$, will probably get heat exchangers on Brian's headers. my current headers have heat exchangers but really hope to find the $$ for Brian's.

I had started a thread on the 930 forum about elec heat. problem is the amount of amps needed to generate any significant heat. so my plan B as loosely described.

[Daves911L]

Originally Posted by carwash

Thx for the push guys. Heat is staying.

Will need to trouble shoot while disassembling, as currently no heat comes out of the defrost window ducts. Air yes, controlled by the knob lever I pictured, but it just controls amount of air, it's always the same temperature.

The caffeinated canine correctly urges you to read your owners manual. The way of Porsche is logical, but often very different from the way other cars work. A lot is explained in the manual that if you were just to assume what something is for, or how it works, you could be wrong. Directing hot air is a great example.

Do you get heat now from the floor vents, but not to the base of the windshield? There are quite a few SWB cars that are missing the black plastic slides over the floor heat vents. If these are missing, or just open, no heat will flow to the base of the windshield.

That photo in the post just above is wrong for your car. That is the LWB control valve, which replaced the function of the extremely simple and effective plastic slides in 1969 and later.

[javadog]

SWB heater slide:

[911tracker85]

That photo in the post just above is wrong for your car.

I knew that, just tossing out ideas. but suspect he could do something similar and simple in his car. I live just a few miles from him and have seen his car, but did not poke around under there to see how the older ones work.

[carwash]

I have those slides yes. They spit out tons of hot air. When I close them I get no more heat at the windshield.

[javadog]

So start at the front of the rocker panels (inside the car) and follow the air ducting up through the dash to the bottom side of the dash vents.

Do you have the optional blower?

JR

[javadog]

Bottom side of the driver's side dash vent on a car equipped with the optional blower motor in the smuggler's box.

Blue arrow - path of fresh air from the outside, controlled by plastic lever under dash.
Red arrow - path of heated air from duct coming off of forward end of rocker panel, through the dash bulkhead.
Green arrow - path of forced air from optional blower motor, if equipped.

[RDUNCe30]

When I rode motorcycles, I used a Gerbing electric jacket and thermostat and it was toasty on my bikes (BMW R1150RT and R1200R) at 32F when worn under an uninsulated textile riding jacket at 65 mph plus.

If you want to run headers with no heat or alter/experiment with your heating system, maybe a Gerbing jacket or vest (can be found on sale at times at big discount) plugged into your cigarette lighter would provide a short term solution to keep you warm on early morning drives. The thermostat is really needed to turn back the heat once you are warmed up. Or you can save dollars by skipping the thermostat and just unplug. Doesn't help a foggy windshield though...

Sam