Heating

Heating Overview:

The heating in the Type 1 Volkswagen is notoriously poor. If all the seals are new, and the motor is able to get to its proper operating temperature,then in my experience, the heating system is able to heat the incoming air to approximately 30 deg. above ambient. This is almost acceptable down to around freezing, at 32 deg. outside the car temp. is around 62 deg., almost comfortable . But what if the outside temperature approaches 0 deg.? Well I'm here to tell you it's not fun. With the cold moist air hitting your windshield at around 30 deg., not only are you numb from the cold, but your glass is icing up on the inside !!

Several things come into play to determine how warm the air is coming out of your heater. The first thing , is the temperature of the air going into your heater. In a stock aircooled Volkswagen, this is the outside temperature, as the air is drawn in from the outside by the engines cooling fan and through the heater boxes. A common modification, is to draw the air from inside the car via fans, and blow this air through the heater boxes. The advantage of this is that your re-heating the same air, thus, raising the temperature at each pass. The disadvantage of doing this, is the current draw of a fan powerful enough to push enough air to do any good is more than the stock generator can safely provide if the headlights are on at the same time , and the fan adds considerably to the noise inside the car. Even with the disadvantages, I believe this modification is well worth the effort. Since my car is not going to have a stock generator anyway, I will just add the current draw of the fans to the current rating of my alternator. As far as the noise is concerned, I plan to mount the fans in a acoustically dead box under my rear seat on the drivers side. Another consideration is the amount of surface area in the heater box available to transfer the heat from the exhaust to the air passing through it. Since I am installing a Type IV motor, and plan on fabricating a custom exhaust, I am going the extra yard, and plan to build custom heater boxes as well. Instead of having the inlet and outlet at opposite ends, like the stock units, I plan to have both at the same end. I will accomplish this by having the box divided down the middle by a partition. In this way, the air will travel down one side, and back down the other. This will double the amount of time the air has to pick up the heat. In addition, I plan to have twice as many fins, half as thick as the stock heater boxes have. I believe this will substantially increase the efficiency of the heat transfer. Finally, to paraphrase an old axiom "a BTU saved, is a BTU earned". The stock insulation in the bug, is in a word, pathetic. I plan to fill every cavity with urethane foam, and fill the space above the headliner with rockwool batting.

Well that's the general idea for my heater that works, I plan to post the details later.