How much space is there between the gas tank and the floor on a 914? Due to the high cost of fuel we are planning on bringing our 914 out of winter hibernation to lessen our dependance on my wife's Blazer. Since the car is liquid cooled I am thinking about using heated air coming from the radiator to heat the car. I want to put a duct running from the front trunk to the interior foot well passing under the fuel tank. Does anyone know how much room there is?

Brian Roth

i'd say about 3-4 inches....if you have a swaybar, this takes up some space, but even with one, there is plenty of room to do what you want to do...I'd make the tunnel from sheetmetal and weld it to ensure that the firewall does not become comprimised

Cool. I have a mid 70's 911 front end. The kind with the swaybar mounted to the suspension sub frame instead of passing through the body.

I do not think the air coming off the radiator is going to be as warm as you think
it is going to be. The air flowing over rhe radiator will not be heated enough to bring heat into the car.... You may end up bringing in cold air rather than warm air.

there is someone else on the list that is heating up his car in the same method, sure it might not be as toasty as having the heater core right under the dash, but it works

if the radiator setup is done correct, most of the air should be flowing thru it....there will be heat

But there won't be any heat until the engine warms up enough to open the thermostat. Could easily be 10 minutes of driving on a cold day before you even start getting a hint of heat. Not great for defrosting the windows in the morning.

Demick

you would also need a fan or something to convince the warm air to go into a sealed (sort of) cabin instead of out the normal path to freedom. Either that or run with the windows down and that would kind of defeat the purpose.

It would be almost as easy to install a small radiator in your fresh air blower that would be tied to the in and out hoses of the main radiator and use that as a heater core.
or you could plop down the big bucks and get a renegade heater system that actually works right
Naw, I'm too cheap too.

I do plan on installing a blower fan. I also agree that it is going to take awhile for the thermostat to open and the air to heat up. The front trunk sure gets hot usually but I have not tried driving the car when it is cold out. Perhaps I will block off 1/2 of the air inlet to the radiator for winter driving if necessary. It is good to hear someone is using this idea with at least some success. It sounds like an elegant solution to me.

Last I checked it was in the >$350 range and you had to have their new water pump. Adding a heater core increases the chance of air pockets, ask Paul Smrz. I've read where someone fabricated heat exchangers similar to the stock to utilize the exhaust heat. You could wire an electric heater made for cars (much like a hair dryer). Chris 914n6 in Las Vegas had a simple heater solution and was working on a heat/cold system awhile back. I don't think the radiator heat will be sufficient unless it's well contained . You should capture the heat in the hose from the engine somehow.
Good luck!
Felix

I'm mounting one of these in my V8 car. Can also be piped into the defrost. Right at $100

Bob

http://161.58.79.191/cgi-bin/SoftCart.exe/...cstore.cfg+842H

Yesterday I started doing some measuring and concluded that there is less than one inch of clearance between the sheet metal hump over the steering rack and the bottom of the tank. So, I abandoned the idea. Instead I used a heater core for a Ford something that I bought at a garage sale. I made a shroud for it and used a 914 blower fan to suck through it and blow through the stock driver's side heater channel. I connected the heater core through the inlet to the stock water to oil oil cooler on the 2.3 turbo. After getting it all installed I could not get the fan switch on the dash to activate the blower wires (if I found them: green and brown?). I must admit, after four 914's I still don't fully understand how to turn on and adjust the heater. However, I am pretty certain there is a problem in the fan switch circuit. I tried swapping around the round relays on the regulator plate and still nothing. If the fan signal goes through the relay how does the amperage change to run the fan at different speeds?

What about putting the heater core and blower back in the engine compartment and routing the plenum hoses through the factory (!) heater tubes? Factory ventilation controls would still work. Couldn't you get a water supply off the intake manifold?

-datapace

Bob,
Nice, got any pics in the car?
Felix

datapace,

That's what I did! I guess my post was too wordy.

Brian,
Can you provide pics? This is lower than up in the dash, thus less chance of air pockets or flow problems.
Felix

Hi Brian, no, I am just an idiot. I had this thread in my mind for a day or so and didn't catch your post before I posted.

would be nice to see some pics. I'll probaby be doing something similar and wanted something to rip off ... er, for inspiration before I actually start

-bryan

I drove the car 47 miles to work this morning. It was so nice to be back in the car after driving my Civic for the past 3 months. That car is so hooked up. I put heavier springs in the rear since I last drove it too and now it does not bottom out any more. Plus I fixed my broken rear sway bar link and it corners so flat, just like a 914 should. It is nice being able to pass any car any time by nailing the throttle and/or downshifitng. Anyway, on to the heater. It works pretty well if you like having various engine fumes being blown into the cabin. I am going to try some kind of cover to get it to draw clean air from under the car. As it is now the air intake faces right at the engine. I have an oil leak so I smell that and some exhaust. With the driver's window cracked it wasn't bad. The air flow was adequate and the temperature was pretty good with it being about 35 degrees outside. Of course I was probably driving under the influence of carbon monoxide. I can probably come up with some pictures in a few days. Also, I need some help sorting out those heater controls. I can't get 12v at the stock heater fan lead no matter how I switch the controls. I tried swapping the round relays and changing dash fuses. I have a lame Haynes wiring diagram.