This one'll stump you all.......

[8v-of-fury]

Nifty heater my good sir.

[rabbitman]

Nifty heater my good sir.

Thanks, I think it's probably saved my life a few times haha. Puts out some hot air, just not a lot of volume.

[ORCoaster]

Well we got us a heater heating a heater here or what?  If I understand this setup you are removing heat through the stock core so you can keep the defroster and such working.  Then if there is heat still left in the coolant you run it through a second core with a second fan behind it?  Not sure I can tell from the picture.  So heat from core #2 is dependent on residual heat from core # 1 and the amount of air being pushed through it. 

At -45 degrees you are completely cooling your car with these two cores I am sure of it.  If you have air blowing in through the engine bay, like most of us do and can't stop it, then you are getting all you are going to get.  The only thing I think left for your setup is a very high temp thermostat.  Or consider an electric accessory heater.  Don't you have a monster battery in this or is that 8 V that does.  Big battery equals inverter plus electric heater that is low enough watts to use without major mods to the electrical system. 

Time to wrap the front end up like they do the big rigs.  Underpan to keep air out. 

[8v-of-fury]

Me gots 1000 cca But a measly 65a alternator.. Tdi swap will have 120amp booyeah. Its got coolant glow plugs right in the coolant neck feeding the heater core!

[R.O.R-2.0]

Me gots 1000 cca But a measly 65a alternator.. Tdi swap will have 120amp booyeah. Its got coolant glow plugs right in the coolant neck feeding the heater core!

that do basically nothing but waste power.. they dont even heat up the coolant faster.. there kinda a waste of time, or atleast thats the general concensus..

[rabbitman]

ORcoaster, the aux heater comes second but blows WAAAAY notter air than the stock heater ever blows, I know it will seem hotter since it has interior air blowing through it but it starts heating before the stock heater ever dreams of making heat.

-60F this morning, bunny not happy. The interior never got above about -45F haha........

[R.O.R-2.0]

ORcoaster, the aux heater comes second but blows WAAAAY notter air than the stock heater ever blows, I know it will seem hotter since it has interior air blowing through it but it starts heating before the stock heater ever dreams of making heat.

-60F this morning, bunny not happy. The interior never got above about -45F haha........

theres not enough air passing THRU your heater core.. its all going AROUND it..

[Lonewolf]

Maybe a daft suggestion, but could the blower motor be spinning the wrong way? kind of sucking the heat away rather than blowing air through the matrix? is that a possibility?

[R.O.R-2.0]

Maybe a daft suggestion, but could the blower motor be spinning the wrong way? kind of sucking the heat away rather than blowing air through the matrix? is that a possibility?

you can spin a squirrel cage fan both directions, and it will still push air the same way. just pushes more spinning one way, than it does the other..

[rabbitman]

I have air coming out the vents so no problems there.

I'll have to tear into this again, sometime.....maybe.....it's starting to feel like I've done it before......like at least 10 times.

[commuter boy]

I'll have to tear into this again, sometime.....maybe.....it's starting to feel like I've done it before......like at least 10 times.

At anything below -25F you won't get much heat, period.  As someone else said, it's too efficient an engine.  We had the same problems with MKI and II's when I was a kid in eastern Canada.   You learned not to breathe in the car so the windows wouldn't fog up   

[Smokey Eddy]

That's massively cold. I'm willing to bet the engine doesn't get hot enough for you to even notice...
in -30c (-22f) my car blew cold air all the time so long as it was moving (and i know my t-stat isn't stuck open).
try letting it idle and get up to temp for at least 15-20 minutes then turn on your heat...
that's crazy cold...
What do you use for fuel at -60F?

[rabbitman]

That's massively cold. I'm willing to bet the engine doesn't get hot enough for you to even notice...
in -30c (-22f) my car blew cold air all the time so long as it was moving (and i know my t-stat isn't stuck open).
try letting it idle and get up to temp for at least 15-20 minutes then turn on your heat...
that's crazy cold...
What do you use for fuel at -60F?

They winterize the fuel here, works good but if you have a car sit 'til winter with summer fuel you'll have issues for sure.

[billybobf]

ok, so, your aftermarket heater is pulling air from in the car and heating it right? your factory heater is pulling outside air and trying to heat it correct? I think that may be your problem? turn the factory heaters blower fan OFF, does the aftermarket heater get hotter? turb it back on, aftermarket cool down a little? with the tempt you are talking I wouldnt be supprized if there just isnt enough heat going through the core to compensate for the cool air its sucking from OUTSIDE.