That's it, i need heat! (Where's the freezing smilie?)

Took the 914 to work today. It's nice enough outside but *cold*. I'm not really looking forward to the drive back tonight.

I'm thinking about making my own heater boxes that go around the headers. Can't be that hard to do.

How about those heated seat inserts? Like the ones that Paul S did on the car featured in excellence a few months ago? Maybe thats enough.

Naaa, my butt is fine.

I guess i'm spoiled. I'd like to have warm air coming out of the vents.

So are you saying you need an ass in your face?

Is she cute?

For me heat's not an option, it's mandatory. I drove in my car on a 60F day and even 60F in the car is not comfortable.

Good luck with your heater box.

What kind of steel will you use?

Yea, but kinda hairy

Ive been wanting to try this.
http://www.google.com/products/catalog?hl=...ed=0CHYQ8wIwAQ#

I thought your oil cooler lines provided the heat in the cabin...weather you want it or not.

Yes, but that is on the list of things that need to be fixed.
Plus, you need to drive quite a bit for those to get hot enough.

My work commute is only 20 miles each way, not nearly long enough for the oil lines to radiate any significant amount of heat.

...there was a discussion here a while back around the merits of HEs, gas (dangerous), and electric. One of the EV guys was using a ceramic heater. I don't have details other than he was running it off a standard 12v battery separate from the car power source.

Very appropriate thread. -4 degrees wind chill here in Flagstaff!! A lot different than the Bay Area. I think these heat exchangers could be made and put around the headers but you should have a Carb. Monox monitor; the headers are made from mild steel and will rust out and leak. Ideally, everything should be made from stainless steel.

I have some old 911 3.2 heat exchangers/exhaust system I would be willing to try; what kind of plans are we thinking about?? Stainless steel headers and exchangers?

Andy do the B&B heat exchangers put out any heat? They look to small to be worth a dam.

The headers i have are ceramic coated stainless steel. I doubt they will rust any time soon.
The idea is to make heater boxes out of stainless sheet-metal and clamp them around the pipes (no welding).

Kinda like the ones PMS sells, but without the $2300 pricetag:

Here's a pic of my headers, looks like there's plenty of space for some boxes:

You've been away from Germany too long. You are becoming a weather wimp. Lace up the combat boots, wear your LONG camo pants and man up.

I know.

The fact that my GF grew up on a tropical island doesn't help either.
The heater at my house has been running 24/7 for the last two month at 70(!) degrees.
And she's still complaining about it being cold.

Andy,

Not sure this will help... but Brian (bird board -- rarlyl8) has been building headers for the 930 crowd, and as part of that has had some experience of adding heater boxes to his headers. Thread is here:

http://forums.pelicanparts.com/911-930-tur...ct-headers.html

Happy holidays dude

kim.

Thank you Sir!

The heat in Florida will not let up. Last year was the coldest December on record, this one has barely been below 80 degrees.

I'm currently running the fan and sweating in 84 degrees.

He resells the B&B heat exchangers. I have read tons of complaints that the heat is terrible with them and the fitment also sucks.

I've heard similar complaints about the B&B version. I only posted the pic above for reference.

I think making custom heater boxes that work is doable.

How about one of those cool shirt set ups, only with hot water instead...

I think you are right, Andy. Removable heat exchangers look very "doable" and you have what looks like "room to spare". General aviation has done something like this under the Experimental banner on Homebilts.

You have talked me into replacing my headers (mild steel) with the stainless steel ones and trying the heat exchanger build.

Thanks, Andy.

Steve Hurt

Racer Chris has a heat exchanger that he attaches to his (four-cylinder) headers. He may have advice, or you may be able to get one from him that fits...

I wonder how much heat you'll get with the ceramic coating?

--DD

Yeah, me too. I think the boxes will need a divider to run double length ...

Andy, I had these on my plane and they worked great. I don't know if this would be an apples to apples comparison because of the difference in power settings. BTW, before buying a "store bought" heat muff I made my first one. I took an old MAPP bottle, cut it in half length wise, installed a full length "extruded" piano hinge and welded in a couple of 1 5/8" nipples for the in/out connections. GL

Just wear long jons.

Yup, that is what I'm going to do at the UFO event on New Year's Day. Or maybe wear my LL Bean jeans with the flannel liner.

Funny, but it doesn't matter what the outside temperature is at an event. Even without a windshield you're never thinking about how cold it is...

An important question is how much of the header pipe must be encapsulated to produce sufficient cabin heat. That depends on how much heat you want.

I’ll assume the goal is 5,000 BTU’s per hour (exceeding the capacity of an alternator to generate electrical heat). The second question is the header pipe operating temperature. In biomass combustion heat exchange calculations often based on a rule that one square foot of heating surface is required to produce 2,000 BTU/hour. Using that ratio for a header pipe diameter of 1.5 inches, 2 linear feet of pipe = one square foot of surface area. Therefore, five linear feet of exhaust pipe might be considered to radiate 5,000 BTU/hour. With 20% heat loss, you must encapsulate about 6 linear feet of header to capture 5,000 BTU/hour. Looking at the stock H/E, that is approximately correct, as they look to contain roughly three feet of “header” pipe each.

The laminar tendency of air flow through a hot pipe makes me think that minimum clearance between the HE shell and the header is ideal. I assume that’s why the stock H/E shell appears “streamlined.” If the enclosure is a high volume box, the heat exchange will be less efficient and more header will required for a given heat production. A contraflow set-up between the heat source and the gas being heated is conventional and that is how the stock H/E flows. Insulation of HE shell has been found to substantially increase H/E efficiency.
To get 5,000 BTU/hour into the heating system of the care you need:
6 feet enclosed section of exhaust.
Minimum clearance of H/E shell that permits sufficient hot air flow
Round tubes rather than a box for the shell.
Hot air flowing in opposite direction of exhaust gas.
Insulated shells.

Good luck.

I found the best solution was to bite the bullet and find some original -6 heat exchangers. Or, find an Eberspacher heater and plumb that into the system. Big money in either case!

Huh?

Those are words, sorry to confuse you.

I always appreciate forums when engineering types chime in. There are ceertain physical laws that don't change, regardless of our opinions.

Just wish I had a mind that could work that way! That's why I usually try to stick with things that the factory engineered for me ( I don't have to reinvent the wheel), unless it was just done to make something cheaper, not better.

I'm nowhere close to an engineer, but the physical rules ("engineering") of gas/air heat exchange are universal and easy to understand. Using wasted exhaust heat for climate control in an air cooled vehicle is a no-brainer. One problem is that Porsche/VW heat exchangers, while effective, are not very durable, and the exhaust configuration of the stock version is not ideal for high performance. Moreover, replacements are expensive and in limited supply.

Constructing H/E requires fabrication of sheet metal -- an activity that is by definition time consuming and requires skill but is not expensive, while success offers comfort and greater vehicle utility. These facts legitimize any discussion for an alternative or "homemade" H/E design. I've spent 30 minutes researching and 30 minutes typing in response to the OP question and the more I think about it the more interesting and potentially useful is the speculation.

In keeping with the advice of another post in this thread, I'd start by obtaining a preformed cylinder (or tubing) of sufficient diameter, and cut and fit it to the headers after attaching the appropriately sized "nipples" (inlet/outlet). I'd love to know the source for the 1-5/8" nipples described earlier.

I know by direct expereince that Eberspacher, or the other brand of gas heaters, are an excellent design and produce tons (literally) of heat. The system is just as safe as a carburetor. It is, however a complex and expensive way to heat a vehicle.

Thanks for the clarification, now lighten up. Geesh....

I was promised a global heating!

It may have been 1.5", I don't remember. It was scrap tube in my shop. I'd like to add this: The area of the plane's cabin was similar to the 914. It was 42" wide and just a drafty. Being a low wing configuration it had the advantage of solar heating ,also. We called it the "fish bowl" effect. The planes insulation was = or< a 914. However, the temps I encountered were much lower than most will see in a 914. Our MN bothers, excluded. I was told that some "bush" pilots wrapped chain around the header within the HE, or heat muff in this case, to increase output. I questioned this but never tested it to prove or disprove. I was more concerned with the chain wearing through my headers. A/C headers are expensive and I didn't want any carbon monoxide fumes from a worn header. Again, used an extruded hinge or the vibrations will eat up your hinge. The advantage of the aluminum heat muff is weight and wear. The aluminum will wear at contact points rather than your header. Hope this helps.

sorry Imissed thisClamp-on aircraft HE