So this weekend I did a lot of tinkering to put my curiosity to bed on heating a car with headers. I remember reading from Dan Root's -6 conversion thread that he welded some pipe to his headers and pushed air through with a stock heater fan.

Sorry no pics now but, I can explain somewhat. I tacked a bent pipe in perhaps 20 places along the length of this bent pipe to the left hand primary tubes. I did insulate the header plus pipe in 1" header wrap. When I attached the blower and ran at idle for maybe 10 minutes I measured the duct surface temp at the driver footwell to be 87 deg. with a good supply of air flowing out. I do think that perhaps the dual oulet blower ( 1 side is capped) from an early car does blow a bit too hard and may need to throttle down that motor or perhaps replace with a bilge blower.

I do realize that this is not ideal and the C0_1 hazard but these are not permanent and I will inspect in the spring when defrost is no longer needed for corrosion etc..

Now, if I do replace the fan or throttle it down, more heat soak should occur between the heater pipe and the air traveling through. Additionally I have not road tested only idled so I anticipate more heat as I piddle around town regardless of cfm through the hose.

Does anyone have an idea about how much cfm the 71 dual oulet blower should blow?

Details; Patrick headers, DE header wrap 1", wrapped to headers for perhaps 1 foot, the remainder is merely insulated.
87 deg vent temp with 20 outside temps (idling). Air being drawn in beside the trans.
Click to view attachment

You could build a stainless steel container attached to the header with welded tabs. The container should be two sided - one side with the cockpit heating air and the other side where the exhaust pipes pass through. It would be something like a cockpit heating system found in general aviation. The flexible heat tolerate hoses on each end and tied to the butterflies and the fan system. Nothing new about this type of heating system. Also, you should use a carbon monoxide monitoring system in the cockpit.

The worse case found in such a system is the possible leaking as the header system wears out. Periodic inspection could be used to make sure the exhaust side is ok. I personally do not like exhaust heating source systems. I am doing something a little different since I am interested in both defrosting and heating. I live part of the time in the hight country of Arizona. Yes, we do have cold and snow in the winter months in Flagstaff - 7,000 ft.

Best of luck and with the proper materials should work great. Always be aware of the carbon monoxide!!!!

Steve Hurt

Steve Hurt

Thanks for the input Steve. I agree that a SS chamber is most ideal, These are mild steel headers and I recall reading somewhere of dissismilar metals accelerating corrosion. Either way this is definately not a permanent solution merely an experiment if you will to satisfy my curiosity about "would it work". I have looked some into the aviation HE's for inspiration and I dont see the surface area within for effective heating. I will admit that factory SSI's are most ideal and probably best for my mild engine but, I already had a header installed so...

One thing I haven't looked at is the CFM of light aircraft vent. blowers. As that may lead me where I want to be with regards to air output.

Ok, I half answered my question, Aircraft "swamp coolers/evaporators" flow 250CFM.

http://www.aircraftspruce.com/catalog/pspa...kpitcoolers.php

I may try a bilge blower or similar and throttle it down to see whats best at least for my application.

Sorry, but I don't think you'll get enought heat to do anything. You'd be better off just to put on a set of HE's in the cold weather.

Do you really think that the original fan blows 250cfm??

I would be very curious to know as I have a one sided heating system (passenger side capped off) and I really want to improve the heating so I can use the car in the winter more..

I'm thinking of two bilge blowers instead of the original fan, but I can find bilge blowers with 100cfm and am now wondering if they would be up for the job?

With regards your want for heat on headers, I would use a larger flexible aluminium tube (large enough to swallow the header) fitted over a length of pipe, have a fan BLOW the air through it and then connect to the heat pipes in the sills. no need for the flapper boxes then as it is now using the engine fan to blow heat, so when you want heat, just turn the fan(s) on..

The flapper boxes are still nice because you don't want any heat oozing in when it's 100 degrees out. I tried an electric fan on a bug without any flappers once years ago and the heat always seemed to come through when it was hot enough out to roast a pig inside my car. Not that I ever did roast a pig inside my car, but it seemed possible.

Rod, I didn't mean that the stock blower flowed 250 cfm, I just found that as a possible representation of what another manifold heater system uses.

I did get the feeling today that slowing the fan would allow more conduction of heat into the pipes and then into the airflow. Too much air...in my application cools the pipes off too much. I tried this by using various resistors in the power lines.

Unfortunately, I think the bushings in my fan motor have died rather epically... it went from a bit noisy to grinding to I unplugged it. I may end up having to get a bilge blower just to see what happens. It should allow cleaner routing.

RE: CFM of these air pumps. disregarding rpm of the elec. motor and making a whole bunch more assumptions. I can see a 4" blower specs at 230ish cfm, a 3" at 120, so our 2" blower based on just area pi*r^2

Hows this for some BS math

4 INCH, 12.56^2 230CFM

230/12= 18

3 INCH, 7.065^2 120CFM

18 * 7.065=128

2 INCH, 3.14^2

18 * 3.14=57

So I don't know what to make of this and they are diff. fans but take it for what it is. Please don' kill me for the quick math, I am just thinking out loud.

I happen to have a dual outlet fan and a airflow meter sitting on my shelf. I might have to check for giggles.

1. Do NOT weld to your headers! Never. If you look at the SSI's, the sheet metal for the heater boxes is not welded to the tubes anywhere.
Welds can crack and leak and you'll wake up dead the next day.

2. Just get a gasoline heater. The modern units are small and quiet and they produce more heat than you'd ever need in a 914.
I used to have a Eberspächer gas heater in my VW Bug. Sauna inside at -20C outside ...
http://www.eberspaecher.com/servlet/PB/men...6_l1/index.html


Andy

Fan volume isn't the issue, it's heat transfer.

I'll 2nd what Andy says about the welds. Do a search, I've posted on this topic before. The dangers are real and the consequences can be lethal.

Eberspächer in English:
http://www.eberspacher.com/products/air-heating/
Anyone know of a US dealer?