Ventilation fan unit

[gouldsborough7]

As most of us will have found, when our soft or hard top roof is in position, the interior of the car gets a bit steamy - when the weather is damp I mean!! Windows get misted up, and it is not very comfortable.

With the usual limitations in dash-board space, my rebuilt layout could only accommodate one largish plastic vent in front of the gear-laver area. I have yet to install some 63mm dia elephant trunking to pick up fresh air from the front of the car.

CBS have a very nice fan unit that fits into the 63mm dia trunking, but at a cost of more than £90!! They claim it is of high quality and good performance, but the cost is really prohibitive.

I was wondering whether anyone has any alternative ideas. I was thinking of a larger fan inside a metal container, with a large intake scoop at the front, and a flange for the 63mm pipe at the rear. Siting it somewhere under the bonnet could be a problem though.

To encourage a through-put of air, I will also install a couple of plastic vents somewhere at the back.

Any thoughts on a fan unit, homemade or otherwise?

Cheers
Mike

[Dane_Rescueman]

Re: Ventilation fan unit

Mike,
I have just travelled this route and will publish the end result as soon as I finish it. I have ripped out the old Cortina plastic fug stirrer and installed the CBS 4.5 Kw heater in its place. I will soon have a small scoop on the NS bonnet top to supply fresh air to the assembly. The heater supplies air to the screen vents and to two CBS low profile adjustable outlets each side of the centre console. I am just designing a simple water trap prior to cutting the last bits of metal. I have MoT next Tuesday and have had a few teething troubles tuning in the new Vulcan 2.1 (Pinto) injected lump. It ran for the second time today !
I'll let you all know about the heater when all is finished, which will be soon.

[keith_h]

Re: Ventilation fan unit

I made a unit from the Sierra donor cars heater. I stripped out the 3 speed fan and heater matrix and threw everything else away. Essentially I made a rectangular aluminium box with 4 outlets on the top and one on each side. It has flaps inside to direct the heat from feet to windscreen and dash center outlet. I think I still have the original drawing I did for Pitstop (over 12 years ago now) if you are interested.

[gouldsborough7]

Re: Ventilation fan unit

Thanks Guys
My problem is that having assembled a totally new dash, I am loath to start stripping things out again. If I can locate a smallish fan, possibly of axial type, put it in a fabricated box with one outlet for the trunking, this might do the job. Whether one largish vent I have installed in the lower/centre of my dash will provide enough throughput of air - only time will tell. Where I am going to site such a contraption is another problem!

Cheers
Mike

[christel.stockden]

Re: Ventilation fan unit

On the same subject of ventilation, but more to the back of the car, here are some pictures of our mod to keep the rear window demisted! A heater/blower assembly, salvaged from a BMW 3 series cabriolet, fitted to a cut-out in the rear bulkhead and using the existing wiring in the original loom to the heated rear screen. It was easy to fit, does the job, draws only 10 amps and supplements the poor heating from the front of the cabin.
We think it is a neater layout to the "stick-on" heater alternative and can be used for hard-top and soft-tops alike.

[gouldsborough7]

Re: Ventilation fan unit

The BMW blower looks good to me. I could probably do with 2 of them - one for the front vent I have been writing about, and the second to copy the installation at the back. But, where will I get them? Any ideas?

Cheers
MIke

[christel.stockden]

Re: Ventilation fan unit

Hi Mike,
My partner, who breaks/repairs/sells 3/5 series BMW's and with whom I share a workshop, has ONE for sale at €30.00. Let me know on [email protected] if you are interested and I could bring it back to the UK on my next visit in a few weeks time and post onto you.
Rgds, Neville

[gouldsborough7]

Re: Ventilation fan unit

Just to finish this item off, I received the BMW fan unit from Neville (many thanks for your help & time) and fitted it to my Berli. This wasn't as easy as it sounds, and needed some surgery to the unit to start with. I decided that I wouldn't use the heater element and anyway this part of the casing was too bulky to fit in the only available space i.e. under the bonnet, adjacent to the exhaust pipes at a lower level.

I was then left with a square hole on the casing to fit a similar sized round hole of the trunking to the vent in my dashboard. I made up a fibre-glasss adaptor, based on lightweight gauze to create the shape and to provide strength. To fit the fan casing to the car, I made a wooden mould, adding fibreglass to create a very snug fit. The combined assembly is now bolted to the top of the chassis.

After that, it was a fairly simple but time-consuming job to cut a hole through to the inside of the car. The only route was between the pedals, with the trunking carefully strapped as it wound its way to the lower dashboard area wher the vent is sited. A simple on/off toggle switch controls the operation. The fan is not all that powerful, but I am hoping that with roof ON, and in damp cold weather, I wont be all fogged up as before.

I have a couple of plastic slotted vents still to fit somewhere at the rear of the car. My theory is that, to make the air flow through the car more efficiently, there should be a positive exit point as well. I know that there are all sorts of gaps with Berlis, but no harm in providing a few more.
Cheers
Mike