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914World.com _ 914World Garage _ Ideas On Auxiliary Heating Systems
Posted by: MikeInMunich Apr 20 2018, 12:15 AM
Greetings once again from Munich!
It’s cold over here when the sun goes down, not to mention nice days in March, April, October and November. I need heat, and I don’t have it because my engine has headers.
I am thinking I will need a high output alternator if I’m using only 12v in order to get the necessary output.
Is this somehow a bad idea? 
Questions:
How would a e.g. 50 amp alternator affect power and gas mileage?
Would it have any effect on the electrical system?
Can you recommend a heater for this application?
Other suggestions on how to best get heat into the cabin without heat exchangers?
Here is an article on PTC (positive thermal coefficient) heaters...
https://link.springer.com/content/pdf/10.1007%2F978-3-642-11628-5_51.pdf
Thanks for your feedback and advice!
Mike in Munich
Posted by: dansvan Apr 20 2018, 12:49 AM
Gas powered Webasto or Espar?
Posted by: MikeInMunich Apr 20 2018, 01:31 AM
Gas powered Webasto or Espar?
Yes, good options. Would be mounted in front trunk, with exhaust going through wheel well. And the heat? Suggestions on how / where to best duct it into the cabin? ALL of my front ventilation system is currently not present.
Any thoughts on my other questions?
Posted by: sb914 Apr 20 2018, 05:57 AM
Heated seats !
Posted by: Cairo94507 Apr 20 2018, 06:24 AM
Heated seats and Ben's heat exchangers.
Posted by: mepstein Apr 20 2018, 06:30 AM
Every year guys talk about the gas fired heaters but I’ve never seen one installed in a 914, just the same picture of one. Heated seats are your easiest option. The best option is to install ss heat exchangers. The huge comfort they provide on even the coldest days more than offsets the couple hp you might loose. It’s a stock system so parts are available and it bolts right in. No brainer if you want a very comfortable car in the winter.
Posted by: Mark Henry Apr 20 2018, 07:13 AM
Every year guys talk about the gas fired heaters but I’ve never seen one installed in a 914, just the same picture of one. Heated seats are your easiest option. The best option is to install ss heat exchangers. The huge comfort they provide on even the coldest days more than offsets the couple hp you might loose. It’s a stock system so parts are available and it bolts right in. No brainer if you want a very comfortable car in the winter.
Gas heater, good solution, I believe no one has installed one because they don't want to cut holes in their cars.
12v way too much load for way too little heat. Heated seats work OK, only viable 12v solution.
Heat exchangers, still the best solution.
Posted by: porschetub Apr 20 2018, 05:14 PM
Played with electric,didn't spend a lot (luckily),total waste of time,too much current draw as mentioned ,I use heater fan set on full speed for demist and have deleted heater control,works good enough .
Not really that cold here but would be different in Germany.
Posted by: dansvan Apr 20 2018, 05:28 PM
The webasto and espar units while not cheap, fit inside a small shoebox, the exhaust tube is an inch in diameter at most, and could be easily ducted into the system.
Attached thumbnail(s)
Posted by: 98101 Apr 21 2018, 01:10 AM
I'm in a similar situation. Thinking about this option next winter if I'm feeling like spending a lot of money by then:
http://www.tangerineracing.com/914headers.htm
Posted by: MikeInMunich Apr 21 2018, 01:24 AM
Played with electric,didn't spend a lot (luckily),total waste of time,too much current draw as mentioned ,I use heater fan set on full speed for demist and have deleted heater control,works good enough .
Not really that cold here but would be different in Germany.
I was thinking about using a high output alternator for this purpose and taking the power straight from that. Honestly don’t know much about the feasibility of this possibility. Still waiting for comments on THIS in particular. Aren’t there 12v heaters out there that need about 50 amps to put out about 10,000 btu / 3000 w or similar?
Posted by: Mark Henry Apr 21 2018, 06:36 AM
Played with electric,didn't spend a lot (luckily),total waste of time,too much current draw as mentioned ,I use heater fan set on full speed for demist and have deleted heater control,works good enough .
Not really that cold here but would be different in Germany.
I was thinking about using a high output alternator for this purpose and taking the power straight from that. Honestly don’t know much about the feasibility of this possibility. Still waiting for comments on THIS in particular. Aren’t there 12v heaters out there that need about 50 amps to put out about 10,000 btu / 3000 w or similar?
Your money go ahead, but VW guys have been chasing this for 60+ years with poor results.
Even big modern alternators can only handle around max 800 watts.
There was a guy last year that bought a $200 espar china copy diesel kit from evilbay, did he ever install it?
Posted by: Luke M Apr 21 2018, 07:25 AM
What are the water cooled conv. guys running?
Wonder if there's a way to install a heater core and warm the coolant somehow?
Maybe plumb hot oil from front cooler through heater core then to cooler?
Most oil coolers run 180 degrees or so which should be plenty to heat a 914 cab.
Just brain storming and I'm sure I'm not the only one thinking about this.
Found this setup on Jegs :
https://www.jegs.com/i/VPA/960/11301-VUX-A/10002/-1?CAWELAID=230006180037964064&CAGPSPN=pla&CAAGID=44693592161&CATCI=aud-194567928791:pla-215314521911&CATARGETID=230006180039219312&cadevice=c&gclid=EAIaIQobChMI5vuSlbzL2gIVxB2BCh3RgQg5EAkYECABEgKmpvD_BwE
Posted by: jim_hoyland Apr 21 2018, 07:35 AM
Warmer clothes ? Layer up... 
Posted by: Luke M Apr 21 2018, 07:43 AM
Warmer clothes ? Layer up...
Lol.. maybe in sunny CA but not up here in the NE.
It's April 21 st and temps are still in the 40's here.
I plan on heated seats for my 6 as I'm running headers. If I need heat or a/c I'll drive the Audi.
Posted by: Mark Henry Apr 21 2018, 08:05 AM
Oil isn't the greatest for heat transfer, you have to run a thermostat, the engine needs to be warm first (180F). By the time you are getting noticeable heat you are already at your destination.
Again bug guys have BTDT, it works to a certain extent but it's poor a result for the effort. To get enough usable heat the oil heat kits of the 70's-80's recirculated cabin heat, which causes fogging/moisture issues.
BTW I know someone is going to say "but my oil cooler puts out bitchin heat"... when it's 70F+ outside of course it does. Try the temps at closer to the freezing point with a thermostat and forced air over the cooler.
Posted by: GeorgeRud Apr 21 2018, 12:02 PM
I was also searching for heat options for my 914-6 conversion when it was running headers. I even bought a used Eberspacher gas fired heater to install, but ended up finding some factory heat exchangers that I had ceramic coated and installed instead (Ben’s heat exchangers weren’t available then). Though the gas fired heaters put out tons of heat for such a small compartment, I think using Ben’s heat exchangers (or some SSI for a four) will end up being the easiest and most workable solution.
Posted by: Dave_Darling Apr 21 2018, 12:33 PM
If you're handy at fabrication, you may be able to make some heat exchanger wrapping for your header pipes. As we've seen from Tangerine's similar setup, the output isn't huge amounts of heat, but it's more than good enough to clear your windscreen. And it will be available quickly, unlike heat coming from water-based coolant.
Mueller looked into wrapping tubing around header pipes and pushing glycol through there with an electric pump, but consensus was a lot of work for relatively little benefit. You'd need to wrap the outside of the wrapped pipe with something like header wrap to keep the glycol from cooling off too quickly, and insulate it until it got where you wanted the heat.
Any way you go, you'll need to put some air distribution stuff back into the car. The stock stuff is easy and is known to fit, but you can fake up stuff if you're creative.
--DD
Posted by: SirAndy Apr 21 2018, 08:53 PM
http://www.914world.com/bbs2/index.php?showtopic=8825
Posted by: porschetub Apr 22 2018, 02:56 AM
I researched this extensively for my car...not that I really will need it.
Small motorhome diesel powered unit would be a possibility and would only require a very small fuel tank as these units are efficient ,I haven't really checked these out fully however.
My early tests involved using my A/C in my late model Audi to demist and then the ambient cool air ,both worked....I won't move ice/frost from the screen but that's not an issue for me,my setup directs all the air from the airbox fan to my screen with the option to feed air out the kneepad vents in the summer.
No real easy answers really without heat-exchangers.
Posted by: Mark Henry Apr 22 2018, 09:28 AM
I looked at why a Tesla doesn't use a heat pump, apparently an auto would have a major icing issue due to moisture, rain, snow, etc. Tesla uses basically a water heater to heat coolant.
You could do something similar with an Espar hot box, where you heat coolant. You would of course still have to plumb it, need a heater core, diesel tank, coolant tank,etc, etc, but the hose would be much smaller lines to run.
Posted by: edwin Apr 23 2018, 08:02 AM
I've been seriously considering buying one of the Webasto style diesel heaters out of china.
Slightly less to go wrong than a cheap petrol heater.
2kw normaly advertise less than 0.5L/hr which means most of us could use a tiny 1-2L aux tank and be comfy for hours.
Did I mention they are less than $300 of our slightly more useless Australian dollars?
https://www.ebay.com.au/itm/12V-2KW-Diesel-Air-Heater-for-RV-Motorhome-Trailer-Trucks-Boats-2000W/142544786789?hash=item213054d565:g:jvYAAOSwMhda1wMk
Posted by: Mblizzard Apr 23 2018, 02:25 PM
While you lose some of the instant heat, I would go with the oil as a heat source. While that can become complex an inexpensive sandwich plate with the oil routed to 2 round oil coolers small enough to fit in heater tubes. Not sure of the heater tube ID but on a quick search found the coolers down to 3-inch in diameter.3-inch PVC has Id of 3.068 inches. Oil cooler approximately $33 in cost. 
Make a cap to fit the ¼-inch oil lines through and 2-1/4 inches square and 1-inch thick 12-volt fans that slides over the heater tubes. 2-fans are about $60. Of course, with a little work and flexible tubing you could use the stock fan as well. 
Not sure how much heat would be generated from the surface area but depending on how much could be placed inside the heater (found them in 12, 15, and 18 inch lengths) they should be capable of putting out a lot of heat.
Wire the on for the fans to the heater lever via a relay and you’re done.
Of course, variable speed fans would give you more control of the heat but his should be easy to do. As another option if the oil cooler won’t fit inside the tubes or you did not want to buy 2 oil coolers you could use one cooler inside a tube external to the heater tubes with flexible hoses running to each heater tube. Could also work with stock fan.
Posted by: McMark Apr 23 2018, 02:29 PM
Is your car 4cyl? Cause I can get you a 250amp alternator that'll fit. Then shop for 12v heaters for truckers/tractors/lorries/etc. 
http://www.my12voltstore.com/product_p/sd12-5000.htm
DC Thermal 12 Volt Ducted Heater - Direct Hook-Up - 50 Amps, 600 Watts - 10,020 BTU
DC Thermals heaters are hand built in the USA with only the very best parts, motors, and wire. These heaters are not constructed of snap together plastic, and cheap internal parts. DC Thermals heaters are designed to last you a lifetime, not a season. DC Thermal heaters will work in any vehicle with a DC electrical system including cars, trucks, vans, busses, heavy equipment, etc. Measures 9"x5"x4" and will easily fit into tight spaces. Vents and Hoses are not included. They can be purchased separately. Part Numbers: DCT-defrost, DCT-Horizon
DC Thermal SD12-5000 � another winner from DC Thermal, a leading manufacturer of 12 Volt Heaters offers various easy to use models of portable 12 volt heaters.
Features
Available with 2, 3, or 4 vent outlets
Adjustable Fan Speed
Heater Dimensions: 9�x 5� X 4�
12 Volt, 50 Amps, 600 Watts
10,020 BTU�s
Brushless 50,000 Hour Ball Bearing Fan
10,000 Hour DC Thermal �RuCar Vacuum Sealed Elements.
Case Construction: T5052 Aluminum.
Wired Entirely with GXL Wire
HIGH and LOW Heat Settings.
Thermally Protected
TWO YEAR Parts AND Labor Warranty
Posted by: Mblizzard Apr 23 2018, 05:51 PM
Is your car 4cyl? Cause I can get you a 250amp alternator that'll fit. Then shop for 12v heaters for truckers/tractors/lorries/etc.
http://www.my12voltstore.com/product_p/sd12-5000.htm
DC Thermal 12 Volt Ducted Heater - Direct Hook-Up - 50 Amps, 600 Watts - 10,020 BTU
DC Thermals heaters are hand built in the USA with only the very best parts, motors, and wire. These heaters are not constructed of snap together plastic, and cheap internal parts. DC Thermals heaters are designed to last you a lifetime, not a season. DC Thermal heaters will work in any vehicle with a DC electrical system including cars, trucks, vans, busses, heavy equipment, etc. Measures 9"x5"x4" and will easily fit into tight spaces. Vents and Hoses are not included. They can be purchased separately. Part Numbers: DCT-defrost, DCT-Horizon
DC Thermal SD12-5000 � another winner from DC Thermal, a leading manufacturer of 12 Volt Heaters offers various easy to use models of portable 12 volt heaters.
Features
Available with 2, 3, or 4 vent outlets
Adjustable Fan Speed
Heater Dimensions: 9�x 5� X 4�
12 Volt, 50 Amps, 600 Watts
10,020 BTU�s
Brushless 50,000 Hour Ball Bearing Fan
10,000 Hour DC Thermal �RuCar Vacuum Sealed Elements.
Case Construction: T5052 Aluminum.
Wired Entirely with GXL Wire
HIGH and LOW Heat Settings.
Thermally Protected
TWO YEAR Parts AND Labor Warranty
Don’t get me wrong, I almost put in that high amp alternator during the last engine drop. But at $200 plus for the alternator and another $200 plus for heater that you have to squeeze in an already tight space it seems like an option that uses most of the the original equipment might be easier.
Posted by: mepstein Apr 23 2018, 06:42 PM
Different year, same thread.
Posted by: Dave_Darling Apr 24 2018, 08:36 AM
While you lose some of the instant heat, I would go with the oil as a heat source.
Or you could go with something that costs even less and works almost exactly as well:
-Nothing at all.
--DD
Posted by: mepstein Apr 24 2018, 10:28 AM
I don’t understand why guys don’t like the ss heat exchangers. Jake Raby said they are good for up to 165-170hp engines. They are totally bolt on, reasonably priced and replacement parts are available. The system is light weight and works great.
Posted by: Mblizzard Apr 24 2018, 11:51 AM
While you lose some of the instant heat, I would go with the oil as a heat source.
Or you could go with something that costs even less and works almost exactly as well:
-Nothing at all.
--DD
OK so I am not sure I see a connection. Are you saying you cant get sufficient heat from engine oil?
Quick calculation indicates that a small oil cooler with just 1 meter of surface area could transfer almost 900 watts of heat if the oil was at 180 and the outside temp was 30F.
Posted by: Mblizzard Apr 24 2018, 11:59 AM
I don’t understand why guys don’t like the ss heat exchangers. Jake Raby said they are good for up to 165-170hp engines. They are totally bolt on, reasonably priced and replacement parts are available. The system is light weight and works great.
That's what I am running now. I am OK with the heat they make but it could be better and you always have that engine smell in the car.
I just think there might be a way to solve it for people that don't have heat for what ever reason.
So I have ordered some of the parts and will see if this is even possible.
Posted by: mepstein Apr 24 2018, 12:07 PM
I don’t understand why guys don’t like the ss heat exchangers. Jake Raby said they are good for up to 165-170hp engines. They are totally bolt on, reasonably priced and replacement parts are available. The system is light weight and works great.
That's what I am running now. I am OK with the heat they make but it could be better and you always have that engine smell in the car.
I just think there might be a way to solve it for people that don't have heat for what ever reason.
So I have ordered some of the parts and will see if this is even possible.
The heat on high should be burning you out of the car. check your connections. There really shouldn't be an engine smell. Again, check your connections. You may need to clean out your heat exchangers. You can get your local mechanic to use a smoke machine to make sure there are no cracks in the headers. This can be done with the heat exchangers on the car.
I also shove a vacuum hose from the engine compartment down the longs to get out dust and dirt and whatever animal has crawled in.
Posted by: Mblizzard Apr 24 2018, 01:04 PM
I don’t understand why guys don’t like the ss heat exchangers. Jake Raby said they are good for up to 165-170hp engines. They are totally bolt on, reasonably priced and replacement parts are available. The system is light weight and works great.
That's what I am running now. I am OK with the heat they make but it could be better and you always have that engine smell in the car.
I just think there might be a way to solve it for people that don't have heat for what ever reason.
So I have ordered some of the parts and will see if this is even possible.
The heat on high should be burning you out of the car. check your connections. There really shouldn't be an engine smell. Again, check your connections. You may need to clean out your heat exchangers. You can get your local mechanic to use a smoke machine to make sure there are no cracks in the headers. This can be done with the heat exchangers on the car.
I also shove a vacuum hose from the engine compartment down the longs to get out dust and dirt and whatever animal has crawled in.
All that is done an good. As far as the engine smell I am not sure I see how it is possible to completely eliminate that. The impeller and blower fan intake air from the engine compartment. The least bit of oil on the heat exchangers when stopped or moving slow always makes it into the engine compartment and then to the inside of the car.
Certainly it can be varied by m
Posted by: Rand Apr 24 2018, 03:01 PM
Warmer clothes ? Layer up...
Lol.. maybe in sunny CA but not up here in the NE.
It's April 21 st and temps are still in the 40's here.
Seriously? 40s? You mean above freezing or below? LOL That's not cold. I still commute on a bicycle when it's that warm.
I dress for how I need to be comfortable OUTSIDE. Then the car is just warmer.
Defrost is the real hassle, but a coating of RainX inside and out of all glass can help big time with that.
Posted by: Dave_Darling Apr 24 2018, 08:22 PM
OK so I am not sure I see a connection. Are you saying you cant get sufficient heat from engine oil?
Quick calculation indicates that a small oil cooler with just 1 meter of surface area could transfer almost 900 watts of heat if the oil was at 180 and the outside temp was 30F.
If you have a 1-square-meter oil cooler (that's a big one!!) how long do you think it will take to get your oil to 180F when the ambient air is 30F?
If you're letting the car idle, it will be somewhere between 20 minutes and never. If you're driving, I hope you've got the windshield cleared off already, but it will still take 5 or 10 minutes to get anywhere near that.
So I exaggerated a little bit, but the point is that for most of us the oil-fed heater core isn't going to provide any appreciable warm air when we need it.
--DD
Posted by: Mblizzard Apr 25 2018, 06:41 AM
OK so I am not sure I see a connection. Are you saying you cant get sufficient heat from engine oil?
Quick calculation indicates that a small oil cooler with just 1 meter of surface area could transfer almost 900 watts of heat if the oil was at 180 and the outside temp was 30F.
If you have a 1-square-meter oil cooler (that's a big one!!) how long do you think it will take to get your oil to 180F when the ambient air is 30F?
If you're letting the car idle, it will be somewhere between 20 minutes and never. If you're driving, I hope you've got the windshield cleared off already, but it will still take 5 or 10 minutes to get anywhere near that.
So I exaggerated a little bit, but the point is that for most of us the oil-fed heater core isn't going to provide any appreciable warm air when we need it.
--DD
You are correct on the delay! Not sure that I did my math correctly. I think the surface are would be about only.4SM which does bring down the potential output to about 360 watts.
Going to play with the concept a bit just for fun.
Posted by: 98101 Apr 25 2018, 08:33 PM
You are correct on the delay! Not sure that I did my math correctly. I think the surface are would be about only.4SM which does bring down the potential output to about 360 watts.
Going to play with the concept a bit just for fun.
Possibly due to my front-mounted oil cooler, on cool Seattle winter days (generally well above freezing) my oil temperature gauge will take about 10 minutes of driving to budge off the 50C floor. It might take 30 minutes of driving for it to get to 80C (176F). That's the highest I've seen it.
I still hope you do this experiment because models and assumptions often turn out to be wrong.... and I'd love another option for getting heat.
Posted by: 98101 Apr 25 2018, 08:47 PM
Seriously? 40s? You mean above freezing or below? LOL That's not cold. I still commute on a bicycle when it's that warm.
I used to commute on bicycle in any weather, and never knew what my girlfriends were complaining about in my 914 with no heat. (As an aside, it seems the same women who are attracted to the *idea* of a convertible in the early dating phase will the be ones asking for the top to be on later.)
My wife simply wouldn't go with me on the motorcycle without heated gear. Once I tried heated gear, I was hooked. I did a ride without it and felt that being so cold affected my judgement and especially my enjoyment.
In my Miata, having a good heater means I can leave the top open more than I could otherwise.
So I'm happy to join the wimp club. I'd love to have a heater in my 914. Didn't need one today though.
Posted by: Garland Apr 25 2018, 10:26 PM
For me, it was around 40 years old, when I started running with heat exchangers. Best long term solution for heat. And yes I did try using a 12v window defroster. Right!
Posted by: wysri9 Apr 26 2018, 02:25 AM
For my stripped competition/road car I am going for a heated windscreen :-
http://www.heatedwindscreen.com
and hoping reduced padding on the rear bulkhead will allow some heat to come through. I am not planning on running in winter on the heavily salted Scottish roads though.....
Posted by: Edward Blume Apr 26 2018, 05:11 AM
While you lose some of the instant heat, I would go with the oil as a heat source.
Or you could go with something that costs even less and works almost exactly as well:
-Nothing at all.
--DD
Long underwear, assuming you wear underwear.
Posted by: Dave_Darling Apr 26 2018, 10:13 AM
In my Miata, having a good heater means I can leave the top open more than I could otherwise.
So I'm happy to join the wimp club. I'd love to have a heater in my 914. Didn't need one today though.
Heh, I still remember getting pulled over by a cop in a "no cruising zone" (enforced because of gunfire happening there earlier in the week) while on my way home from a 4-midnight shift at work. The cop gave me grief about how cold I must be with the top off. I sad, "the heat works fine, I'm warmer than you are right now!"
I'm lucky there wasn't anything wrong with my car and I wasn't speeding, so he couldn't write me a ticket for having a big mouth....
--DD
Posted by: mepstein Apr 26 2018, 11:11 AM
In my Miata, having a good heater means I can leave the top open more than I could otherwise.
So I'm happy to join the wimp club. I'd love to have a heater in my 914. Didn't need one today though.
Heh, I still remember getting pulled over by a cop in a "no cruising zone" (enforced because of gunfire happening there earlier in the week) while on my way home from a 4-midnight shift at work. The cop gave me grief about how cold I must be with the top off. I sad, "the heat works fine, I'm warmer than you are right now!"
I'm lucky there wasn't anything wrong with my car and I wasn't speeding, so he couldn't write me a ticket for having a big mouth....
--DD
It is nice to crank the heat and drive with the top off on a chilly day. Keep the windows up and it's comfy inside.
Posted by: SirAndy Apr 26 2018, 12:57 PM
Funny, when i went with the "out the top of the hood" vent for my large front mounted oil cooler *everyone* told me i would end up with a sauna in the car whenever i take the top off and my car would lose 500hp because it would now ingest boiling hot air coming over the roof.
Btw, neither of those predictions became reality ...
Posted by: Dave_Darling Apr 26 2018, 03:41 PM
I believe I didn't say either of those things. I did say that you'd get reverse air flow because the lid was a high-pressure area.
Turned out I was wrong.... 
--DD
Posted by: Rand Apr 26 2018, 04:03 PM
Seriously? 40s? You mean above freezing or below? LOL That's not cold. I still commute on a bicycle when it's that warm.
I used to commute on bicycle in any weather, and never knew what my girlfriends were complaining about in my 914 with no heat. (As an aside, it seems the same women who are attracted to the *idea* of a convertible in the early dating phase will the be ones asking for the top to be on later.)
My wife simply wouldn't go with me on the motorcycle without heated gear. Once I tried heated gear, I was hooked. I did a ride without it and felt that being so cold affected my judgement and especially my enjoyment.
In my Miata, having a good heater means I can leave the top open more than I could otherwise.
So I'm happy to join the wimp club. I'd love to have a heater in my 914. Didn't need one today though.
I completely understand and respect the wimp club, even though I often comment like I did for fun. I have a car with creature comforts too. I just won't go down that road with my 914. It's not the car for that.
Bottom line that seems to keep being regurgitated year after year is: The best electric option is heated seats. You cannot heat and defrost your car from a 12v source. STOP trying. "Capn' I cannotta change the laws of physics."
Heat exchangers just work. The most solid solution.
The gas heaters can work great, you just have to be willing to go through a proper installation.
Keep seeking another solution if you want to waste your time. Or come up with something that hasn't already been tried and proven to fail around here.
Posted by: MikeInMunich Apr 27 2018, 01:28 AM
Seriously? 40s? You mean above freezing or below? LOL That's not cold. I still commute on a bicycle when it's that warm.
I used to commute on bicycle in any weather, and never knew what my girlfriends were complaining about in my 914 with no heat. (As an aside, it seems the same women who are attracted to the *idea* of a convertible in the early dating phase will the be ones asking for the top to be on later.)
My wife simply wouldn't go with me on the motorcycle without heated gear. Once I tried heated gear, I was hooked. I did a ride without it and felt that being so cold affected my judgement and especially my enjoyment.
In my Miata, having a good heater means I can leave the top open more than I could otherwise.
So I'm happy to join the wimp club. I'd love to have a heater in my 914. Didn't need one today though.
I completely understand and respect the wimp club, even though I often comment like I did for fun. I have a car with creature comforts too. I just won't go down that road with my 914. It's not the car for that.
Bottom line that seems to keep being regurgitated year after year is: The best electric option is heated seats. You cannot heat and defrost your car from a 12v source. STOP trying. "Capn' I cannotta change the laws of physics."
Heat exchangers just work. The most solid solution.
The gas heaters can work great, you just have to be willing to go through a proper installation.
Keep seeking another solution if you want to waste your time. Or come up with something that hasn't already been tried and proven to fail around here.
So 12v and e.g. 100 amps from a high output alternator is unfeasible?
M.i.M.
Posted by: Edward Blume Apr 27 2018, 04:12 AM
Heh, I still remember getting pulled over by a cop in a "no cruising zone" (enforced because of gunfire happening there earlier in the week) while on my way home from a 4-midnight shift at work. The cop gave me grief about how cold I must be with the top off. I sad, "the heat works fine, I'm warmer than you are right now!"
--DD
Sounds intimate. Was this on Sunset strip?
I'm confused though... was he the "John" or were you?
Posted by: Mblizzard Apr 27 2018, 10:21 AM
Seriously? 40s? You mean above freezing or below? LOL That's not cold. I still commute on a bicycle when it's that warm.
I used to commute on bicycle in any weather, and never knew what my girlfriends were complaining about in my 914 with no heat. (As an aside, it seems the same women who are attracted to the *idea* of a convertible in the early dating phase will the be ones asking for the top to be on later.)
My wife simply wouldn't go with me on the motorcycle without heated gear. Once I tried heated gear, I was hooked. I did a ride without it and felt that being so cold affected my judgement and especially my enjoyment.
In my Miata, having a good heater means I can leave the top open more than I could otherwise.
So I'm happy to join the wimp club. I'd love to have a heater in my 914. Didn't need one today though.
I completely understand and respect the wimp club, even though I often comment like I did for fun. I have a car with creature comforts too. I just won't go down that road with my 914. It's not the car for that.
Bottom line that seems to keep being regurgitated year after year is: The best electric option is heated seats. You cannot heat and defrost your car from a 12v source. STOP trying. "Capn' I cannotta change the laws of physics."
Heat exchangers just work. The most solid solution.
The gas heaters can work great, you just have to be willing to go through a proper installation.
Keep seeking another solution if you want to waste your time. Or come up with something that hasn't already been tried and proven to fail around here.
So 12v and e.g. 100 amps from a high output alternator is unfeasible?
M.i.M.
I think you would need more than 100 AMPs. See http://www.914world.com/bbs2/index.php?showtopic=327849&st=0# Post
Posted by: Mark Henry Apr 27 2018, 10:57 AM
http://www.914world.com/bbs2/index.php?showtopic=8825
With a modern espar or wabaso gas heater this would be a much cleaner install. Plenty of room to put a small diesel tank if you want to use a truck bunk heater. A bunk heater will roast you out. They use them for ice fishing huts up here and they have to be careful not to melt the ice they're sitting on.
On a six conversion, without a relay board, you cold likely mount it in the bay and tie it into the heat tubes without cutting a single hole.
Posted by: Dave_Darling Apr 27 2018, 11:19 AM
So 12v and e.g. 100 amps from a high output alternator is unfeasible?
You'll want to run #00 welding cables from the alt to the battery and from the battery to your heater...
--DD
Posted by: worn Apr 27 2018, 11:33 AM
So 12v and e.g. 100 amps from a high output alternator is unfeasible?
You'll want to run #00 welding cables from the alt to the battery and from the battery to your heater...
--DD
For 1200 watts? Of course you would have to leave some of that behind for the other needs of the car. Step it up 110 with an inverter on the way and the wiring could be an extension cord. Which brings me to the Honda generator in the trunk idea. Small household space heater in the car.
Another idea is to put the webasto in the right rear wheel well and duct into the existing air system.
I want to go to WCR across the Rockies from me. Will I make it without a heat exchanger? The front fan works, and I can bundle up, but I do want to see ahead.
Posted by: mepstein Apr 27 2018, 11:54 AM
So 12v and e.g. 100 amps from a high output alternator is unfeasible?
You'll want to run #00 welding cables from the alt to the battery and from the battery to your heater...
--DD
For 1200 watts? Of course you would have to leave some of that behind for the other needs of the car. Step it up 110 with an inverter on the way and the wiring could be an extension cord. Which brings me to the Honda generator in the trunk idea. Small household space heater in the car.
Another idea is to put the webasto in the right rear wheel well and duct into the existing air system.
I want to go to WCR across the Rockies from me. Will I make it without a heat exchanger? The front fan works, and I can bundle up, but I do want to see ahead.
buy a heated seat pad. plug it into power outlet. fold it up when you get to WCR
Posted by: worn Apr 27 2018, 12:13 PM
[/quote]
buy a heated seat pad. plug it into power outlet. fold it up when you get to WCR
[/quote]
OK. Thanks. Think the cold air will handle the defrost? While it may conceivably snow, I am really thinking about rain and possible wet clothing getting in and out of the car. That can fog things up. I also have some rained antifog.
Posted by: 98101 Apr 27 2018, 01:14 PM
I don’t understand why guys don’t like the ss heat exchangers. Jake Raby said they are good for up to 165-170hp engines. They are totally bolt on, reasonably priced and replacement parts are available. The system is light weight and works great.
I've been advised that the 1 5/8" headers that came with my car are part of why the engine is underperforming for a 2366. (Chris F's opinion here:
http://www.914world.com/bbs2/index.php?s=&showtopic=322371&view=findpost&p=2567229
).
So I'm intrigued by Jake Raby's statement, since I'd love to have heat and defog next winter. Wouldn't I lose more power by going to ss heat exchangers intended for a stock engine?
Posted by: Mark Henry Apr 27 2018, 02:49 PM
I don’t understand why guys don’t like the ss heat exchangers. Jake Raby said they are good for up to 165-170hp engines. They are totally bolt on, reasonably priced and replacement parts are available. The system is light weight and works great.
I've been advised that the 1 5/8" headers that came with my car are part of why the engine is underperforming for a 2366. (Chris F's opinion here:
http://www.914world.com/bbs2/index.php?s=&showtopic=322371&view=findpost&p=2567229
).
So I'm intrigued by Jake Raby's statement, since I'd love to have heat and defog next winter. Wouldn't I lose more power by going to ss heat exchangers intended for a stock engine?
I don't think that quote is correct, for HP Jake always said a proper sized header makes the most power. Ballpark 5% for stock to 15+% on a performance engine. A 180hp engine could lose 25hp with small 1-3/8" ID heat exchangers.
A header is the greatest bolt on HP you can add to your 914.
Posted by: GeorgeRud Apr 28 2018, 01:36 PM
Maybe Ben (mb911) would make some if there was enough demand, but perhaps fabricating some outer envelopes over currently made headers may be a more reasonably priced alternative.
Posted by: 76-914 Apr 28 2018, 05:55 PM
It was interesting to hear Scott? @PMS speak to the importance of not over sizing your exhaust. He showed us one car that never met it's potential until they reduced the size of the collector. He said that was one of the more common mistakes that we, the occasional builder make! This may apply to high output engines only; didn't ask.
Heated seats are a God send. I cannot have mine on high or I'll roast my arse. I have a water cooled conversion and never run the heat unless it's below freezing. Otherwise, I need to roll down a window to blend in some cold air. Before you make any attempt to add heat or AC seal and insulate! Replace the old door seals if they're torn, the old roof seals and plug any holes in the bulkhead including old worn grommets. 
Posted by: larryM Apr 29 2018, 03:27 PM
... perhaps fabricating some outer envelopes over currently made headers may be a more reasonably priced alternative.
EXCELLENT IDEA - should not be all that difficult for someone with the right sheet metal tools - there are clearly some among us who will take on any fabrication challenge
i made a set of templates long long ago off my oem -6 headers, but never bothered to follow thru on the idea (they are on a shelf somewhere)
(oem heat boxes make the routine obligatory tending to the valves etc a major PITA on both -4s & -6s)
- don't need heat in sunny california
- or if i do, i drive the Miata instead - maybe even top-down
Posted by: theer Apr 29 2018, 04:37 PM
I have a water cooled conversion and never run the heat unless it's below freezing. Otherwise, I need to roll down a window to blend in some cold air. Before you make any attempt to add heat or AC seal and insulate! Replace the old door seals if they're torn, the old roof seals and plug any holes in the bulkhead including old worn grommets.
Do tell more of how you are getting heat with a water-cooled conversion. Here in New England, some of the nicest driving days are Spring & Fall when it can get a bit chilly after dark. Defog/defrost is the bigger issue, though.
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