RE: Servotronic

["Dupree, Jim" <dupree@alldata.com>]

Wouldn't this also lower the overall resistance of the circuit and increase
the current flow or load on the controller? Possible burning out the
controller.
Thanks
Jim Dupree
 <mailto:dupree@alldata.com> dupree@alldata.com
Technical Editor II
ALLDATA Corp.
Database Development
(916) 684-5200 Ext. 3346
Fax: (916) 684-5225

	-----Original Message-----
	From:	David Kavanagh [SMTP:dak-ignore@rochester.rr.com]
	Sent:	Tuesday, February 02, 1999 1:38 PM
	To:	quattro@coimbra.ans.net
	Subject:	Re: Servotronic

	I just thought about this again, and a parallel resistor would
divide the
	current going through the rack assist coil. My suggestion about the
series
	resistor was wrong. Anyone want to try it?

	David Kavanagh wrote:
	> 
	> Steve, If I remember my electronics education, putting the
appropriate
	> value (and wattage)
	> resistor in series with the rack would decrease the assist
according to
	> the resistor value.
	> Without doing some measurements, I don't know if that requires .5
Ohms
	> or 1K Ohms (or 1/4 W
	> or 10 W resistor). I suppose if you knew the resistance of the
rack
	> (assuming just two connections
	> to the rack), you could figure out what kind of power was going
though
	> it at 12V and pick the
	> right resistor and see if it "feels" right.
	> 
	>         David
	> 
	> PS. Does the '91 200 20v have the same rack?
	> 
	> "Buchholz, Steven" wrote:
	> >
	> > While looking into some other V8 trivia I found a discussion of
the
	> > Servotronic system ... at least the one for the V8.  In the
description it
	> > showed that the system worked by varying the current through the
Servotronic
	> > valve on the steering rack ... with the amount of assist being
increased as
	> > the current through the valve increased.  Below about 12MPH the
controller
	> > drives the valve to saturation to get the maximum assist, but
above that
	> > speed it showed the speed/current function with the current
going to -0- at
	> > over 100MPH.  This implies that those of us who have
disconnected the
	> > servotronic have set the assist to the amount that it would be
at a much
	> > higher speed.  I don't have a problem with the assist at that
level now, but
	> > it should be a fairly simple matter to rig an adjustable current
source that
	> > would allow the amount of assist to be user selectable.  It
might actually
	> > be possible to "recurve" the existing module to reduce the
amount of assist
	> > at certain speeds, while leaving full boost when parking.
	> >
	> > I don't know if I want to even think about "chipping" my
steering right now,
	> > but it might very well be possible ... :-)
	> >
	> > Steve Buchholz
	> > San Jose, CA (USA)