Date:         Thu, 30 Jun 2005 13:15:53 -0700
Reply-To:     John Bange <jbange@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Bange <jbange@GMAIL.COM>
Subject:      Re: Addendum: Boston Bob Big Valve Engine Update
In-Reply-To:  <42C44753.4090309@charter.net>
Content-Type: text/plain; charset=ISO-8859-1

> Someone a while back posted about work on adapting a "hot" type AFM unit
> for use on a Vanagon.

I believe those Bostig Engineering guys are working on that one. They
did a dyno test not too long ago, but I haven't heard anything since.
Their web site is refusing connection, so I dunno what's up recently.

> Also there was some discussion about
> re-engineering the Idle Stabilizer Control box (in front of the right
> tail light)  into a solid state unit less susceptable to failure.

Heh. That was me. I won't go so far as to call it a pipe dream, but
progress is definitely slow on that project. So far all I've done is
trace out about a quarter of the circuit diagram for the standard
analog unit (thanks to Frank Condelli for providing me with a couple
no-go units to bash on). It's a remarkably complex hand-tuned analog
computer. Being mostly a digital electronics kind of guy, analog
control systems like this are black magic to me. I'm thinking that the
way to really approach this is from the other end: monitor the various
inputs in conjunction with the air bypass valve output in a running
vehicle in order to get the operating parameters. I'm under the
impression/delusion that a digital idle control unit would be
unbelievably easy to implement compared to the analog one, as there's
one thing digital can do that analog can't, and that's COUNT! There
are obviously only a few variations in optimum RPM depending on
whether the AC compressor is on, the engine is warming up, etc. A
digital controller need only count the R's Per M and adjust the idle
stabilizer valve if the number is too high or too low to match the
current "mode". I hope to have the engine into my vehicle soon (it's
been dead since Dec 25, though, so "soon" is very relative) and then I
can start working on "improvements". If my Idle Stabilizer Controller
experiment works, I may even feel bold enough to design an ODB
II-compliant digifant ECU replacement! OK, maybe not. Probably just a
Zemco-style engine monitoring system...