Date:         Sat, 27 Jul 2013 18:02:41 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: afordable alternatives    RE: Radiator fan resistor
Comments: To: Project Pat <psdooley@VERIZON.NET>
In-Reply-To:  <0MQM0024C6LDCO20@vms173005.mailsrvcs.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 05:34 PM 7/27/2013, Project Pat wrote:
>The resistance values and power dissipation should be in the ballpark with
>any other brand.  It would just need to have the same number of stages for
>correct functionality.  And of course the footprint would need to match the
>existing VW part.  That really isn't hard to fix if the mounting hole in the
>airbox is accessible.

Not to say it won't work, but there are a couple things that might be
in the way.

First, that resistor is similar to the Toyota type which if my
experience with a Camry one is typical will glow red and burn out in
seconds on speed ?two? if not in the correct airflow.  The VW one is
a large hollow ceramic core with the resistance element wound around
it and overcoated with ceramic glaze, with tap terminals coming out
the side.  It clips into a steel bracket with prongs that hold the
ends of the core.  It has enormous thermal mass compared to the Ford type.

Second, there is no external access at all.  You have to remove the
dash and then the heater box, and then you have to split the heater
box to get to the resistor.  So there's a big investment involved.

My suggestion would be for an experimental rig to go with an external
resistor or a PWM controller, and do any necessary heatsinking and
ventilation independently.  The motor wouldn't care and you wouldn't
have the high premium on getting it right the first time.

One data point: my measurements on several blowers indicate the front
blower assembly by itself draws about twelve amps from a charged
battery, or ~150 watts.  I haven't got measurements for the resistor
values, sorry.

Yours,
David