Date:         Thu, 18 May 2000 23:56:47 -0700
Reply-To:     Garrett Adams <gadams@JPS.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Garrett Adams <gadams@JPS.NET>
Subject:      Re: Cruise Control
Comments: To: Newtonun@AOL.COM
In-Reply-To:  <c0.3e14e28.26560ea5@aol.com>
Content-Type: text/plain; charset="iso-8859-1"

Ron,

In March 1990 I bought an Equus model 9000A cruise control from Pep Boys.
Cost then was around $125-$150 installed. In use it's not perfect but for me
has been adequate, especially on long boring Interstate highways. The
Vanagon's vacuum unit isn't really up to the job of supplying the necessary
vacuum to the cruise control. This results in my preset speed sometimes
disengaging. This requires a speed up and reset, or in my resuming manual
control for awhile. Also it is not very effective (or efficient)  in hilly
terrain but that's an area where I normally prefer manual control anyway.

From what I understand the factory Vanagon cruise control has its own vacuum
supply rather than feeding off the engine's vacuum.

Reproduced below is a 1997 message dealing with these issues. I'm not sure
if it was from our list or from a newsgroup.

Garrett Adams
83.5 Adventurewagen GL
Stockton, California

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Date: Mon, 06 Jan 1997 15:03:00 -0500 (EST)
From: Porter_Fred%PAX9@mr.nawcad.navy.mil
Subject: Cruise control progress

Today I talked to the Equus cruise control Technical Service dept.
(800-544-4124) and they were super helpful!  I talked with Gene--he has
installed the system on his 84 Westy and had some detailed modifications to
make the system work.  Equus does not recommend the system for the Vanagon
because of the low vacuum levels supplied by the engine.

The vacuum on the Vanagons is not enough to run the cruise control so at a
minimum a vacuum canister with check valve needs to be installed to build up
a reservoir of vacuum to power the servo.  Gene recommended to call Napa and
ask for part no. 250-6019 from the Perfect Circle catalog.  It will probably
look like a can with two ports on it.  It also has a check valve so that
vacuum can be 'accumulated' in the canister.  For junkyard scavengers, look
for late model GM's or call automotive heating and A/C types.  It is
IMPORTANT that the canister have two vacuum fittings and that the flow only
goes one way.  If you suck on one side you should be able to feel it on the
other port in only one orientation because there is a check valve in the can
to permit only one way flow.  Even with the canister, operation at altitude
is still questionable.

Gene suggested hooking up the vacuum feed line to where the line goes
forward to the power brake booster.  Right now, mine is taping off the idle
stabilizer valve connection to the inlet air distributor.  That may be a low
and inconsistent source of vacuum.

Gene also said that a vacuum pump is too powerful.  They typically supply
18-20" of steady vacuum and the unit only needs about 10-16".  Using a
vacuum pump could result in a stuck valve and an inadvertent full throttle
condition.  Yeuch.

Considering the above two scenarios, I think that after I move to Utah, I'll
be modifying my cruise control to have its own independent vacuum pump, but
will run it through a vacuum canister with a pressure relief valve.  This
way I'll be able to have a steady supply of strong but meterable vacuum.
The vacuum pump will be hooked up to the canister which will be hooked up to
the cruise control servo.  If the vacuum becomes too strong for the servo,
the pressure relief valve will allow some air into the system reducing the
level of vacuum.  Having the canister in line will reduce the systems
sensitivity to valve operation and make the vacuum level more consistent.
By hooking up a vacuum gauge on the exit of the canister, I'll be able to
set the release point for the relief valve.  This should allow the servo to
operate at altitude.  For safety sake, the power to the vacuum pump could
also be controlled by a pressure sensor on the canister.  At a minimum, the
power supply to the pump could be in series with the power supply to the
servo--kill both with one wire yank at the fuse block.

If all this fails, Gene recommended an all electric system made by Rostra
(previously Dana) in North Carolina, 910-276-4853

BTW, the stock VW cruise control system for the Vanagons has a vacuum system
independent of the engine.  It has its own vacuum pump.