[urq] WUR findings

[Ben Swann]

We are talking about the CIS Warmup Control Pressure Regulator that is found on the WX.
It is similar to the one found on MC-1 and MC-2 10V turbo, but has two pressure ports
vs. only one for the 5000 turbo.  This hangs off the side of the engine block to
reference the heat from the engine as well as its internal heater bi-metallic strip.

I don't recall the CIS WUR for the WX being plumbed exactly as you indicate - the
5000/200 setup may be a little different.  Re-reading what you are writing a few times,
it sounds like you are referring to the CIS system pressure regulator which is
in/adjacent to the metering head and is a spring/relief valve setup and can be shimmed
to adjust sytem pressure routing return fuel to the tank. That does work in conjuction
with the WUR to adjust/compensate pressure.  I am not going into the CIS pressure
regulation details and actual plumbing as one can refer to a manual and the diagrams to
get confused enough.

The CIS-E and E-III attempt to regulate pressure more electronically than mechanically
as the CIS WUR does.

Ben

-----Original Message-----
From: John Cody Forbes [mailto:cody at 5000tq.com] 
Sent: Thursday, March 26, 2009 4:06 PM
To: Ben Swann
Subject: Re: [urq] WUR findings

Ben are we talking about a CIS remote WUR or the CIS-III electronic regulator? The
normal old fashioned WURs like on an MC engine or your urQ in stock trim don't work like
you say. One port recieves control pressure (pressure applied to the piston in the fuel
metering head to counter-act the airflow induced movement, the other is just a return
line that T's into the return line to the tank. It works to enrichen the engine by
bleeding off control pressure which allows the metering plate to move more easily.

-Cody

Ben Swann wrote:
> Gary,
>
> Without remembering exact  specifics on this, I'll give you enough
> info. to support advice to leave the hose routing as indicated in the
> stock layout.
>
> Basically the WUR has two port on it - one provide pressure to the
> side of the diaphragm that enriches and the other to the side that
> enleans.  Once the temp valve opens, the circuit allows to enrich and
> enlean based on manifold pressure.  It seems counterintuitive at
> first that both sides of the WUR are plumbed into the same pressure -
> wouldn't that cancel out any effect of pressure you likely wondered.
> Me too, so I did some experimenting and somewhere I have notes on the
> results.
>
> What actually happens is the amount of force on the diaphragm is
> disproportional.  As I recall, the port has greater effect on riching
> up the mixture than is does to lean, but that is the part I forget
> exactly and it may be backward.
>
> I played with this thinking I could get more enrichment by separating
> out the two and using other pressure sources - one of them was the
> venturi effect off the throttle and there is one off the turbo hose
> too, as well as some valves and manifold source, and use of an air
> fuel meter.  These all met with various and interesting results, but
> mostly my conclusion in the end was to fix what is broke with the
> stock system and leave the WUR plumbing as it was.  With that you
> could use the WUR to provide enrichment for greater fuel at boost,
> but it is very hard to control with simple valves.
>
> The best way to add fuel if you are upping the boost is some sort of
> EFI - a supplementary injector does fine for modest power levels
> under 300 HP and full EFI like what I did using Megasquirt to dial in
> as much boost and fuel as you can safely with your turbo and other
> setup.  You can also shim the air flow meter, but that IMO is a
> temporary workaround.
>
> I like CIS, but I like EFI better.
>
> Ben
>
> [Date: Thu, 26 Mar 2009 08:45:41 -0700 (PDT)
> From: Gary Brown <gmbchef at sbcglobal.net>
> Subject: [urq] WUR findings
> To: urq at audifans.com
> Message-ID: <84785.75341.qm at web82101.mail.mud.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> A few weeks ago I was having leaning condition under high boost.
> Everything was working as they should, and found that the wastegate
> actuation stud was stripped, causing the diaphragm to lift, letting
> the boost spike. Fixed that, same problem. So...after lots of urq
> list archiving and remembering some of the Bosch book topics, I
> remembered that the WUP on this car was set up for cold running as
> well as boost enrichment, but the hose set up made no sense to me. I
> have tinkered with that before, but never quite figured it out. This
> time, I took an old WUP (CPR) apart, and applied pressure to both
> nipples then vacuum to both nipples. What I found was that the two
> nipples are placed in such a way that the diaphragm moves the same
> direction under boost as well as vaccum, the large one being the
> boost enrichment. What didn't make sense is the on-off switch below
> #5 cylinder plug, with the two nipples on it. It has one hose from
> the manifold going to it, and
> one hose that is teed off to go to both the large and small nipples
> on the WCUPR. When the motor gets warm, the switch closes, and
> therefore no vacuum or pressure goes to the CWPUR. This is as per the
> underhood and IST docs. So....I by passed the switch all
> together...guess what....enrichment under high boost! But, now
> enrichment under decel too. When I re-install the vacuum hose from
> the manifold to the switch and the switch to the small nipple, that
> will take care of that. But, it does sound cool with that rolling
> burble under in-gear decel! I'm sure that this has been written up
> somewhere, but I couldn't find it.
>
> HTH
>
> Gary ]
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