Because it's been so cold lately I have been considering improvements to the heating system.

I was thinking of disconnecting the pipes which go from the fan housing to the heat exchangers and blocking the holes in the fan housing. Then somehow installing small 12VDC electric fans at the entrance to the heat exchangers. The fans could be variable speed and would blow air into the heat exchangers. This would mean that even when standing still a reasonable amount of air would come through the vents and demisting the windscreen would be quicker. I am talking about a type 3, but the same idea could apply to any VW.

Has anybody tried this? Any ideas or opinions?

I was doing this with my bus - til I eliminated the heater boxes!

They way to go is get a working kombi fan from a type IV engine. Wire it up so that it operates via a switch in the cabin. From the two output tubes on the fan connect your heater ducting... run these tubes to the heater boxes.

This is exactly the way the type IV heat is set up.

If you're not interested in heat the same system can be used for fan forced window demisting, skipping the heater boxes straight to the defunct heater channels and up to the glass....

The amount of air from a 12V DC fan would be no where near the out put of a generator driven fan.

The most you can pinch from you generator system is a couple of 100W say .25kW MAXIMUM

When you take your fan pulley off (like a drag car) HP goes up by say 5HP or about 3.5kW - over 10 times the difference

You could get a kombi fan system - but it would not be as good as the original.
Maybe in ADDITION but that would be a LOT of work

ive done it on my 1302 and it works a treat i used bilge blowers that i got from a boating store and fitted them in the heater ducting under the back seat. unfortunately they are still in the car after i wrought it off. the way i did it was the same as hot vw did it last year i think. you can also buy the kits from the states but this is the cheaper option as the fans are about $40 each

Barry, the type IV heater system works in exactly this way (an electric fan). If it moves enough air over thru the heater boxes for a kombi for a bug or type 3 it's gonna be even more effective. Don't forget the air out of the cooling shroud from the gen/alt fan is also going out under the engine.

true

What do modern cars use to blow air into the cabin? I assumed they used an electric fan. Couldn't one of these be used? There's plenty of room under the rear parcel shelf of a type 3 to fit a fan and run some ducting to the heat exchangers. What's this Kombi fan thing? Do Kombis have electric heater fans? What the...?

Obviously the whole point is to get more air than the current engine cooling fan supplies without sucking the battery dry. Considering that the fans primary purpose is to cool the engine, not heat the cabin, I didn't think this would be too hard to achieve.

Kombi's have the air from the cooling fan and also a 'booster' electric fan. It only helps when idling. If you could adapt one of these it may help, but I am sure they draw a fair amount of current and an alternator would be a must.

Does anyone know how much current they draw?