Date:         Tue, 14 Oct 2014 13:28:20 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Vacuum System Parts on 1.9 - "Y's" and Constrictors...
Comments: To: Ryan Perry <rjdperry@GMAIL.COM>
In-Reply-To:  <CAKLYf13_2tGDegoSszQg3Qj6sh3co_uSKxoRAmpHG=Papxjqig@mail.g
              mail.com>
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At 10:46 AM 10/14/2014, Ryan Perry wrote:
>1) I broke the plastic "Y" that connects a large vacuum hose that comes off
>the passenger side of the air plenum that has a small hose coming out the
>side. It was pretty brittle, and I was heavy handed. I have it duct taped
>together but can't imagine that being a long term fix. I am having issue
>finding the part, anyone know where it might be available or the sizing of
>the large vacuum tube so I can find something non VW?

The side arm of that Y contains a 1.4 mm (.055") orifice.  That is
the suction line to ventilate the activated charcoal canister and
pull off the gasoline vapors which have been adsorbed onto the
enormous surface area (something like 40,000 square feet per teaspoon
IIRC)of the charcoal.  The orifice limits the rate of this airflow
(which does not pass through the AFM.


>2) I was reading in the manual about a constrictor in the small vacuum line
>right after the "T" that plugs into the back of the air plenum. Looks like
>right after the T the constrictor headed towards passenger side. I had
>replaced this with a FLAPS "T" and ran the van and didn't seem to notice
>any changes beyond the off idle bog I have been hunting down. Anyone know
>if this is absolutely necessary or how to get one?

That is the control line that operates the valve allowing the first
line to apply suction to the charcoal canister.  It only sees vacuum
when the throttle comes off the idle stop, and the orifice controls
how quickly the valve can open and close.  I don't know why they put
this one in, whether for emissions or driveability or to keep from
injuring the valve.  The orifice is very small, .006 inches or one
and a half times the thickness of a Post-It note.

I've got no advice.  But if you need an orifice and can't find one
p-mail me.  I know I can make a .013 orifice, maybe I can make a
smaller one.  And I can certainly make the larger one if necessary so
you could use a FLAPS tee.

Yours,
David