[urq] WUR findings - Warmup Pressure Regulator

Thu Mar 26 15:39:58 PDT 2009

It is possible to use the WUR to enrichen the mixture under turbo pressure, 
but you would need a so called three stage WUR for this.
A couple of years back I was thinking of doing a turbo project on a car I 
own, and bought such a WUR for this car.
This car uses simple CIS / K-Jetronic. The WUR is adjustable, and it also 
has the ability to give extra fuel when under positive pressure as
under negative pressure.

The company I bought this WUR from is http://www.enginetuner.co.uk/ - ask 
for Alan Jeffries.

/Dag
1990 100 TQ Sport Exklusiv

----- Original Message ----- 
From: "Ben Swann" <benswann at verizon.net>
To: "'Bares, Vittorio'" <Vittorio.Bares at nuance.com>; <gmbchef at sbcglobal.net>
Cc: <quattro at audifans.com>
Sent: Thursday, March 26, 2009 10:09 PM
Subject: RE: [urq] WUR findings - Warmup Pressure Regulator

>I just sent a reply to Cody, so read that for a little more info.  It is 
>helpful to read
> the Bentley to gain some details on the various CIS and CIS-E systems.  To 
> really get
> the whole story, BOSCH Fuel Injection by Probst is the required bedtime 
> reading.
>
> WUR - Warmup Regulator
>
> WUP - something one used to get when they were naughty.  I think was a 
> typo, but could
> perhaps mean Warmup Pressure
>
> WCUPR - A little harder to type, but actully more accurate meaning Warmup 
> Control
> Pressure Regulator and should probably be WUCPR or just CPR which might 
> get confused
> with something that is done then a heart stops beating.
>
> CWPUR - probably another variation on the above.
>
> Most folks call it the WUR or CPR.  In short this device has been used on 
> CIS based cars
> since the 70's or before when Bosch fuel injection came about.  It 
> regulates the control
> pressure that acts as a counterforce in the fuel metering head.  By 
> controlling this
> pressure as the car warms up and also for load related condition (manifold 
> preesure) the
> fuel mixtrue can be enriched for cold starting or heavy load, or enleaned 
> as the engine
> warms up or is cruising.  The devil is in the details.
>
> Ben
>
> -----Original Message-----
> From: Bares, Vittorio [mailto:Vittorio.Bares at nuance.com]
> Sent: Thursday, March 26, 2009 3:46 PM
> To: Ben Swann; gmbchef at sbcglobal.net
> Cc: quattro at audifans.com
> Subject: RE: [urq] WUR findings
>
> I feel dumb...what is:
> -- WUR
> -- WUP
> -- WCUPR
> -- CWPUR
>
> Unless they are the sounds of my car makes when its not working right ;)
>
> Vittorio -
>
> -----Original Message-----
> From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com]
> On Behalf Of Ben Swann
> Sent: Thursday, March 26, 2009 3:36 PM
> To: gmbchef at sbcglobal.net
> Cc: quattro at audifans.com
> Subject: [urq] WUR findings
>
> 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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