I've just hooked up a Kombi demister fan on my rx7 oil cooler above my gearbox. I have the correct 2 stage switch as well. I can only get it to suck air away from the cooler but I really want it to blow air through the cooler.
It doesn't matter which way I hook up the wires & can't get it to blow which is what I beleive the Kombi demisters do anyway.
When I picked it yesterday I tried it on a battery & by just swappping what looks like the earth on the fan from positive to negative I could get the fan to rotate either way & at both speeds.
Any ideas at all would be most apprecciated. I suppose I could just turn the fan around but with it sucking & not blowing air its pushing air back over it's own housing & motor which I'm sure it's not supposed to do according to the bit of Kombi channel that the fan was still attached to.
regards
Jak

Do you have the funky little control box really thing on it or are you trying to wire the fan up directly ?

Do you have the flaps open ?

Put the fan on the other side of the cooler then it will blow through ???

Is the current flow on the motor able to be reversed ??

[Edited on 15-6-2003 by vw54]

I'm not running a relay & CT said that when he had one that he didn't either.
I could just put the fan on the other side but as I said it is then blowing air over itself which is inefficient & I also know that it blows both ways but not the way that I have it wired up. Like I said, by just swapping the wires from psitive to negative on a battery I could get the fan to spin both ways. Why doesn't it do it now?
regards
Jak

.

I've just been out to the garage and had a play with a spare of mine. It does reverse if I reverse the polarity. But the blades in the fan are curved. Its noticably less efficient reversed. "normal" airflow would be from left to right in your picture.

Thanks Chris, I was just about to e-mail u about it since I know u are into kombis. i thought that the 'normal' air flow would be from right to left as I have it in the pic, so it would be blowing air through the cooler??.
I've just tried hooking up the earth on the fan to the power on the switch & then to the fuse box but it just wouldn't do anything. I'm stumped. If I can reverse the action of the fan just by swapping the earth from positive to negative on battery terminal, how do I put that into practise with the switch in the equation?
regards
Jak

I'm 100% certain that normal flow is from left to right. The fan slips into a tube under the dash, those tabs stop it from going in too far. Air is drawn over the motor. up into the dash vents. Buy me a digital camera and I'll take a photo!

I've got no idea why it wont reverse for you now. In any case you should take it out and see the difference in airflow depending on which direction its running.

These fans are pretty noisy. A 12V fan from Dick Smiths or whoever would be quiet and take up less room. probably not as much air flow though.

Yeah, if you reverse the flow it may not deliver as much volume of air. They are not designed to work in reverse.

Yeh Chris the tube that u are talking about cam with the fan, so I know that it's supposed to blow not suck air. These little fans put out huge amounts of air thats why I got one, I may get another when I get this one sorted. I can't hear it from inside the car, & it's only going to be turned on when on the track as thats the only time i need it.
I spoke to a guy at Jaycar electrics today & showed him the pics & explained what was happening. He tends to think that it's all hooked up correctly & that the problem may be that it's not insulated from the car, ie: it's all metal on metal & thats why the fan is earthing itself as a negative rather than a positive making the fan spin the wrong way. What do u think???
Jak

hmm I dont think the earth theory works, the fan motor is insulated by 3 rubber blocks. Would it work if you took the impellor off and turned it around? Or would it still blow the same way.

Just read the article in zeitschrift. Its a good read, well done.

I think that it still blows the same way if the fan is turned around. I thought of that.
I was thinking of just getting a normal toggle switch & running the earth to it & then to power, duplicating the battery test, then put just the high speed wire of the fan to the switch as well.
What do u think
Jak

PS are u coming out for a look on Saturday Chris at Oran Park?

Hey Jak,
I will come for a sticky, what time will you be racing too. I gotta work in the morning. Cheers, Keith.

just looking through your post, what event is on up at oran park this saturday, (circuit racing is it), i am a person interested in this type of thing.
cheers!

Circuit racing it is, and with the Porsches as a back drop (they are nearly as exciting as the Bettles - believe it or not ).
-
How many Beetles do you expect I'll see on Sat Jak ? (Blue cant finish his.)

I started to read the thread but got tired so look at teh pics, I am guessing youhave been told the one you have there is in backwards an will not work properly at all like that.
Also you will find it works like poo without ducting to push air into.

I agree with Brad, for relatively small areas of cooling forced air driven through ducting from an axial fan ( the Kombi one over the engine would be excellent as it is designed to blow through 2 duct tubes that look about the depth of the oil cooler) & you caould mount the fan somewhere out of the way

:alien

Keith,
It runs all day, hope to catch up.

As for the fan I have given up. I've made 3 ducts to force air into the cooler & the fan can suck it out, we'll see how we go.
Thanks again everyone
regards
Jak

What about running the brown earth wire to the main terminal on your starter motor. Then the high speed black wire to a toggle switch, and earth on the other side of the switch. (Thats probably what you have said)

I dont know why you cant run it normal direction though and draw air through the cooler.

Better still. Mount it on the roof with a few teck screws. Bewdiful. Oil coolers are free (in a scrutineering sense) you can do what you like :P

Dont think I will get there saturday. I've got an exam at 2pm.