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Posted by: sgetsiv Oct 20 2014, 10:05 AM

I have headers (of course) and was thinking I could install one of these directly into the factory ducting:

http://www.my12voltstore.com/12_Volt_Ducted_Heater_p/sd12-4000.htm





I still have my booster fan, nice flappers, J tubes and plenty of ducting... they make a 50 amp model as well.

It would need to be located in the engine bay in my opinion...

Posted by: ClayPerrine Oct 20 2014, 10:08 AM

You will need a new, high amp alternator. The stock one only puts out 55 amps.

I put in an electric heater for one winter, and I only drove to and from work. Had to put the battery on a charger every night.

Posted by: GeorgeRud Oct 20 2014, 09:30 PM

Once the car is started, how many amps does it take to keep it running (assuming no other electrical draws other than brake lights and turn signals as required)? I've never heard any numbers on how many amps an ignition system draws.

Posted by: r_towle Oct 20 2014, 09:33 PM

It's interesting that Clay mentioned this.
With two amps, it felt funny when driving with the stereo on full blast, when I turned it off it ran better....

Gotta see who makes a bigger alternator.

Posted by: mgp4591 Oct 20 2014, 09:44 PM

Subaru makes a bigger alternator!

Posted by: r_towle Oct 20 2014, 10:08 PM

Right , 8k for an alternator upgrade.

Posted by: rick 918-S Oct 20 2014, 10:13 PM

Bigger alternator requires more ponies to run it. So I don't know what you have for hp but any gains will likely be negated while running the heater. Fuel mileage will suffer as well.

Posted by: Mark Henry Oct 21 2014, 06:33 AM

A 40amp draw is huge and 8000 BTU is not much when heating a cold car.

We're talking clothes dryer draw (in amps) and the average dryer puts out 22,000+BTU

Posted by: ClayPerrine Oct 21 2014, 06:58 AM

Yea, but the clothes dryer is running a 240V. The car is only running 12V. There is a big difference in the available power between 240V and 12V. A 12V car battery will only get a dryer's heater elements slightly warm.

Here is the math for it:

A 12V heater at 40amps is generating 480 watts. 480 Watts converts to 1638 BTU.

The dryer you list above, at 22,000 BTU is pulling 6447 Watts. That works out to 27 amps at 240 Volts.

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The ignition system on a 914 will only draw a few amps. It is when you start running lights and wipers to deal with the rain/snow/night that you will exceed the output of the alternator.

Posted by: mgp4591 Oct 21 2014, 07:31 AM

True... unless you've already got the swap done.

Posted by: Rob-O Oct 21 2014, 08:18 AM

100 amp GM one wire alternators fit in there like a glove. No more voltage regulator on the board either. I've seen a few of these alternators that need slight maching to fit, but most bolt right in. I've got one in mine and it works well.

Posted by: stugray Oct 21 2014, 08:29 AM

Can we get the "frame number" or part # for the one that fit?

Posted by: stugray Oct 21 2014, 08:33 AM

I saw the numbers posted above and was dubious.

"That works out to 27 amps at 240 Volts."

I dont think that my wife goes out to the garage to plug her hair dryer into my welding outlet (or the clothes dryer).

In the US, the most a hair dryer can pull is 15 Amps @ 110V for 1650Watts.
Most of them are 1200 watts.
Even most electric floor heaters will not pull more than that.

Posted by: Rob-O Oct 21 2014, 08:49 AM

I'll see if I can snap a picture (and get frame/model number info) next time I'm under there.

Posted by: Dtjaden Oct 21 2014, 09:06 AM

Definately snake oil! As stugray stated above 480 watts is the equivelant of 1638 btu's, not 8000. You can't get more power (heat) out than you put in.

To generate 8000 btu's from 12 volts you would need to draw 195 amps.

Posted by: Mark Henry Oct 21 2014, 09:12 AM

Yeh I'm no electrical engineer... my point was that 8000 BTU in a car is not much.

The Subaru why would you do an electric heater?

Even at 100amp alt the electric heater would still be wimpy.

Posted by: Cap'n Krusty Oct 21 2014, 09:22 AM

Uhhhh, your wife drys her hair in a clothes dryer? Nothing in the post referred to a hair dryer.

The Cap'n

Posted by: SirAndy Oct 21 2014, 10:08 AM

Electric heaters in cars do *not* work. They just don't.

Get a gasoline heater and be done with it.
http://www.914world.com/bbs2/index.php?showtopic=113152

Posted by: stugray Oct 21 2014, 10:26 AM

Just put jwalters self-sustaining wind turbine in one of the headlight buckets and you can generate enough power to run a clothes dryer...

Posted by: Dr Evil Oct 22 2014, 08:31 PM

I have a BN4 gas heater that I will sell you

Posted by: VegasRacer Oct 22 2014, 09:20 PM

The P.O. installed an electric heater in Elvira. If I turn it on at night, the headlights dim by almost half.
It does put out a reasonable amount of heat, but the real problem is air flow.
The only time it adds any noticeable warmth to the cabin is if the top is off and both windows are rolled up.

Posted by: mgp4591 Oct 22 2014, 10:22 PM

If it was efficient enough I'd save weight with one of these rather than a heater coil and the associated plumbing, box and the like. You're right tho- I think I'll stick with using the logical method with my Subie engine...