WUR/CPR was Re: [urq] Parts recommendations

[Ben Swann]

Hey - I was looking a Huw's diagram.  This makes more sense, but I don't get
it yet.

See: http://www.humanspeakers.com/audi/vacuum-system.htm

Knowing what each CPR port does would clarify - quattro list in copy in case
anyone knows there - Huw?

This includes a valve  between the larger of the two CPR lines and the tee
and another line directly to manifold.

Hmmm - wonder what is going on here.  One must be for vacuum and the other
for positive pressure, or ???

Ben
----- Original Message -----
From: "Ben Swann" <benswann at comcast.net>
To: "Ingo Rautenberg" <i.rautenberg at waratap.com>; "James Howard"
<spam.me1 at ntlworld.com>
Cc: <urq at audifans.com>
Sent: Wednesday, March 30, 2005 12:45 PM
Subject: Re: WUR/CPR was Re: [urq] Parts recommendations
[Ingo describes what I was talking about , and it just didn't make sense to
me.  To simplify - on my '83(as per diagram under hood)  a line comes off
the thermo time valve/switch and tees off to the 2(two) ports on the CPR -
if the valve is open, then you get manifold pressure, if it is closed then
does nothing.  Perhaps some re-teeing or one way valving can be applied to
make this work better.  My engine seems to be running lean on startup and at
boost, and I beleive it is the CPR - yes fuel pressure test is in order.
Was hoping to try a WUR/CPR from an '83 CGT NA (not turbo) as they look
identical, but have not checked the numbers.  Anyone know offhand?

My setup is not like: http://homepage.ntlworld.com/jh.666/diag.jpg but like
Ingo says - what do the two different ports do specifically - thought one
actually facilitated enrichment under boost.

I thought this WUR could be used to facilitate higher fuel pressure at boost
by lowering control pressure, but from what jim says is not the case.  Also
if the thermo time swith closes rather than opens as the engine warms, then
the tee'd off lines do nothing once the engine is warm - so this could
probably be improved upon.

Uh what is thermo-pneumatic valve?  Maybe it is supposed to work somewhat
with pressure too and not just a temp switch.  Why two ports then?  Does one
work under vacuum and one under boost - which is kind of what I thought.

Ben

text edited in earlier messages to remove >>garbage >> as they are one of my
hangups in reading something.  Megots to get ETKA running and recover all my
info - too much to dooo!

----- Original Message -----
From: "Ingo Rautenberg" <i.rautenberg at waratap.com>
To: "James Howard" <spam.me1 at ntlworld.com>; "Ben Swann"
<benswann at comcast.net>
Cc: <urq at audifans.com>
Sent: Wednesday, March 30, 2005 9:56 AM
Subject: Re: WUR/CPR was Re: [urq] Parts recommendations


> Jim,
>
> I know what Ben is referring to.  Unfortunately, none of the ETKA diagrams
accurately pictures this.  On my car (Ben's as well -- and probably all
other WX motors) the FPR/WR has two vacuum ports nearest the engine block,
one being approx 1/4" whereas the other more closely approximates 3/16".

Curiously, there is a tee combining them and then leading to the
thermo-pneumatic valve.  Maybe just another kluge (aka dumbass) modification
to make this part work on the WX motor --most likely a carry-over from the
previous US type 43 5k turbo.  Should only really require one vacuum
connection, IMO.
>
> HTH
>
> Ingo
>
> ----- Original Message -----
> From: "James Howard" <spam.me1 at ntlworld.com>
> To: "Ben Swann" <benswann at comcast.net>
> Cc: <urq at audifans.com>
> Sent: Wednesday, March 30, 2005 4:49 AM
> Subject: Re: WUR/CPR was Re: [urq] Parts recommendations
>
>
> > Hi Ben,
> >
> > On the WR at least the layout is like this:-
> >
> > http://homepage.ntlworld.com/jh.666/diag.jpg
> >
> > When you say 2 lines going to CPR do you mean the 2 Teed together as per
this diagram?
> >
> > The way I understand it the WR system works as below - I think the WX is
pretty much the same at least as far as warm up goes, not so sure aboutWOT
'cause of the whole frequency valve part on the WX - but I did think that
the duty cycle was maxed out by about 4000rpm (it is on the MB).
> >
When the engine is cold, the thermo valve is open and the mixture is varied
as the amount of vacuum applied to the CPR varies. - The more vacuum
applied(ie closed throttle/overrun) the higher the control pressure and the
leaner the mixture. The 'base' control pressure is lower anyway as the
secondary function of the CPR is to vary pressure with temperature.
> >
> > When the engine is hot, the base control pressure is higher (because the
CPR is hot) and the thermo valve is shut. In a non-WOT condition, only
vacuum is applied (and held) on the CPR via the one way valve and the top
connection of the solenoid valve.
 During WOT the solenoid opens and positive pressure is then applied to the
CPR  via the bottom connection to the solenoid valve to lower the control
pressure and provide WOT enrichment.
> >
> > Basically this vacuum system provides enrichment at partial throttle on
a cold engine, and enrichment only at WOT on a hot engine.
> >
I have done some tests on my CPR with a MightyVac and a fuel pressure gauge.
As vacuum is applied to the CPR, the control pressure rises. Applying
positive pressure to the CPR does nothing - the control pressure is already
at it's minimum at atmospheric pressure. The vacuum system on the car
appears to apply positive pressure to the CPR only to dispell the vacuum.
> >
> > This may give some clues too, although it's WR again :-
> > http://www.isham-research.co.uk/quattro/wr_hoses.html
> >
> > Jim.] ....Snip...