Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > 1- Porsche Technical Forums > Porsche 911 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Mar 2006
Location: wisconsin
Posts: 205
Garage
Cold control pressure graph?

I have an '80 SC which should have a WUR ending in Bosch pn 072 (according to my Bentley manual) The one that is actually in my car ends in 112.

Does anyone have the cold control pressure and warm control pressure specs for this regulator? Again the Bosch number is 0 438 140 112.

I assume I want the settings to be correct per the regulator, as opposed to correct for the year of the car. I know ideally it should have the correct regulator but that is not an option at this time.

Thanks!!
__________________
Brendon

80 911SC "Weissach"
77 930 (in pieces)
Old 04-28-2006, 01:21 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
Scott R's Avatar
 
Join Date: Feb 2001
Location: Aspen CO US
Posts: 14,073
Garage
Re: Cold control pressure graph?

Quote:
Originally posted by brendon
I have an '80 SC which should have a WUR ending in Bosch pn 072 (according to my Bentley manual) The one that is actually in my car ends in 112.

Does anyone have the cold control pressure and warm control pressure specs for this regulator? Again the Bosch number is 0 438 140 112.

I assume I want the settings to be correct per the regulator, as opposed to correct for the year of the car. I know ideally it should have the correct regulator but that is not an option at this time.

Thanks!!
I can't help you on the graph, however I have an 80 that had the "wrong" WUR in it and I was never able to get it set correctly. I purchased a 072 and have no issues now.
__________________
2011 Range Rover Supercharged
2005 Cayenne Turbo
2012 Panamera 4S
1980 911 SC
1999 996 Cab
Old 04-28-2006, 02:21 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Mar 2006
Location: wisconsin
Posts: 205
Garage
I have been working with a P-car mechaninc on this for moral/technical support. He couldn't find any info either but the readings I get seem to be right at the average of all the graphs we have looked at; about 2 bar cold (68 degrees ambient) up to 3.75 bar warm.
__________________
Brendon

80 911SC "Weissach"
77 930 (in pieces)
Old 04-28-2006, 03:11 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Scott R's Avatar
 
Join Date: Feb 2001
Location: Aspen CO US
Posts: 14,073
Garage
Quote:
Originally posted by brendon
I have been working with a P-car mechaninc on this for moral/technical support. He couldn't find any info either but the readings I get seem to be right at the average of all the graphs we have looked at; about 2 bar cold (68 degrees ambient) up to 3.75 bar warm.
Why are you looking at the WUR? Do you have some other symptoms you could post?
__________________
2011 Range Rover Supercharged
2005 Cayenne Turbo
2012 Panamera 4S
1980 911 SC
1999 996 Cab
Old 04-28-2006, 06:16 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Mar 2006
Location: wisconsin
Posts: 205
Garage
Quote:
Originally posted by Scott R
Why are you looking at the WUR? Do you have some other symptoms you could post?
Sorry, I should have mentioned that.

My car does not like to run at low speed and steady throttle. It seems to surge, and it is the worst when it is cold. I have been going through everything just to know where the car is at; e.g. timing, tune-up, fuel system pressures.

I did just replace the vacuum advance on the distributor as that was leaky, but haven't driven the car yet. While the distributor was out I checked the mechanical advance and everything in there seemed to be moving freely.

Knowing that this is not the 'correct' WUR for my model, I am just curious how close the pressures are compared to the proper WUR for my system.
__________________
Brendon

80 911SC "Weissach"
77 930 (in pieces)
Old 04-28-2006, 06:41 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Designer King
 
Paulporsche's Avatar
 
Join Date: Mar 2004
Location: Toronto, ON Canada
Posts: 5,074
As you pointed out, the Bentley does not have a spec for that number. However, if you look @ all the graphs shown, if you had a cold cp of 1.6 bar @ 10C and a hot one of 3.3 you would probably be very close.

I am using an Audi 5000 WUR w/ my modified engine now, and it works OK.

BTW I found that steady part throttle surging in my car was due to a too rich setting, especially while still warming up. You may find your cold cp is a little low, or your mixture is a little rich.
__________________
Paul
Yellow 77 Sunroof Coupe/cork interior; 3.2L '80 SC engine/10.5:1/No O2; Carrera Tensioners; 11 Blade Fan; Turbo tie rod ends; Bilstein HDs; 28 tube Cooler; SSI, Dansk; MSD/Blaster; 16x7" Fuchs/205/50 Goodrich G Force Sport Comp 2; PCA/UCR, MID9
Never leave well enough alone

Last edited by Paulporsche; 04-28-2006 at 08:04 PM..
Old 04-28-2006, 08:01 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
Registered User
 
Join Date: Mar 2006
Location: wisconsin
Posts: 205
Garage
Thanks for the replies.

I have also heard that too lean can cause surging in that situation.

Just averaging all the graphs I have found it looks like my results should be about right. I guess I am just in search of the sweet spot for mixture at this point. I could pay to have everything checked out thoroughly and set properly, but where is the fun in that...
__________________
Brendon

80 911SC "Weissach"
77 930 (in pieces)
Old 04-29-2006, 09:45 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
Jim Williams's Avatar
 
Join Date: Feb 2005
Location: Huntsville, AL
Posts: 1,346
FWIW,

I checked a Bosch Fuel Injection Catalog I have dated 1996, and it doesn't list a 438 140 112 Warmup Regulator. It skips from 110 to 113. This catalog, however is a US Bosch catalog, and doesn't list European parts, that is, Bosch parts for cars sold only on the European market.

So if you want to do do further research, you'll need to find a source that covers European Bosch parts. If you find such a source, please let me know, as I've been looking for one for years.

At one time, Bosch had one on their German language site, but I haven't been able to find it in some time. The URL I had no longer works.
__________________
Jim
www.jimsbasementworkshop.com
(CIS Primer for the 911)
(73 911T (RS look) coupe)
(Misc. 911 Parts for Sale)
Old 04-29-2006, 12:17 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,423
Garage
112 is a Euro designation.
The graphs are very similar, I'd say not signifiantly different.
What is your CO% at idle?
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 04-29-2006, 04:49 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered User
 
Jim Williams's Avatar
 
Join Date: Feb 2005
Location: Huntsville, AL
Posts: 1,346
Brian,

Where did you find the graph for the 112? Do you have a source for the Euro CIS parts?
__________________
Jim
www.jimsbasementworkshop.com
(CIS Primer for the 911)
(73 911T (RS look) coupe)
(Misc. 911 Parts for Sale)
Old 04-29-2006, 06:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,423
Garage
No source for parts but I just sold my spare 112 a few weeks ago. Most of my CIS is now Euro due to replacing US parts with new and used Euro parts.
The graphs I have are from many sources such as Bosch, Porsche factory manuals, and various CIS manuals. When I was tuning my CIS I printed out all of the graphs to see if changing the WUR would cause any problems. The graphs were not significantly different. The WUR works in concert with the fuel head so they are "matched" for the application. What I found out was that I could adjust my US WUR to work better with the Euro head. The US WUR, and particularly the California WUR ran lean as you would expect. It does not take much adjustment to richen them up.
Jim, "bleask" over on Rennlist modifies WURs for very specific and custom applications. Shoot him an e-mail and you will learn more than you ever wanted to know about WURs.

To address the original post, a Euro WUR should work on a US engine with an adjustment from the mixture screw. How well it will work depends on the other CIS components. With my engine I eleminated everything that was not manditory for the engine to run in order to simplify tuning and troubleshooting. It is really difficult to troubleshoot WUR problems in a complex system like that found on California cars.
That being said, surging is "generally" a lean issue. It may not have anything at all to do with the WUR - a vacuum leak in the right place will do the same thing. Any unmetered air can cause a variety of issues depending on where it is coming from.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 04-29-2006, 09:12 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered User
 
Jim Williams's Avatar
 
Join Date: Feb 2005
Location: Huntsville, AL
Posts: 1,346
Brian,

Sorry, the question about the Euro parts came out wrong. I was trying to ask about the sources of *information* about the specs on the Euro Bosch parts, not about the the parts themselves. I didn't word it very clearly. Your post implied you had or had seen, a graph on the 112 WUR, so a source for the information on specs for the various Euro CIS components is what I was interested in.

The graph of pressure versus temperature is what most folks seem to be concerned about, but probably as important is how the WUR pressure changes with manifold vacuum. Once the WUR has warmed up, the pressure is constant except for the changes when manifold vacuum is decreased (or decreased past atmospheric pressure for turbos) as the throttle plate is suddenly opened. For Lambda CIS cars, of course, the vacuum feature on the WURs went away.

The WUR temperature specs were also chosen, I suspect, considering the thermal features of a particular engine, in how fast it "warms up". But the whole story of how all the characteristics of the CIS components were actually chosen by the Porsche and Bosch engineers for each engine model will never be known, I think.

Where can "bleask" be found on Rennlist?
__________________
Jim
www.jimsbasementworkshop.com
(CIS Primer for the 911)
(73 911T (RS look) coupe)
(Misc. 911 Parts for Sale)
Old 04-30-2006, 03:56 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,423
Garage
Jim, I'll look in my pile of old notes and see if I can find that 112 graph for you. You can e-mail Brian Leask at bleask@cox.net (I sure hope he doesn't mind me posting that information, it is listed on a public website).

I agree it is difficult to find information on the various WUR designs. The Bosch book does a decent job of this by showing units that compensate for altitude and boost. As Paul pointed out in his post above you can use a WUR from just about any application and make it work with your engine. A basic similar function exists in them all. If you want to see a good example of CIS component interchangability look at the Fuel Head on a 930 - it has 8 fuel line bungs and is also used on the V8 Mercedes. Many of the components on my mothers' '86 560SL look the same as the ones on my 930 engine.

Brendon, there are a few conditions that cause low speed and idle surging. Generally a rich mixture when warm will manifest itself in an idle occillation that clears up when above 1200-1500rpm. I say generally because I have seen one case where this wasn't so. The engine would idle rough or choppy when cold and surge when warm, no occillation. The mixture was waaaaay rich with a CO of 8%. The problem ended up being a dirty fuel head (you can only imagine how difficult it was to figure that out).
My aproach to "fixing" CIS problems is probably not recommended by true mechanics. Because the CIS is a component system I simply and methodically replace the components until the problem goes away. There are a few CIS troubleshooting spreadsheets floating around that point tward the components involved in various maladies. Normally that number is low. Replace that part with one from a working car (this is where a freindly P-mechanic comes in) and you quickly see what is going on. In the case above where the car ran extemely rich we tried 2 WURs that I had because it just HAD to be the WUR. HA!
Before we began we checked for vacuum leaks. Then we took baseline data (Fuel Pressure in all conditions and %CO) on the faulty running engine - VERY IMPORTANT. Then we replaced the suspect part and again gathered data.
As many on this board have stated you need a Gunson Gas Tester and a Fuel Pressure Guage set to more easily diagnose and repair CIS problems. Another tool that is a huge help is an A/F meter.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8

Last edited by RarlyL8; 04-30-2006 at 05:57 AM..
Old 04-30-2006, 05:53 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
Registered User
 
Join Date: Mar 2006
Location: wisconsin
Posts: 205
Garage
Looks like I may have opened a can of worms here. Thanks for the info and insights.

I guess my next step is to find what what my co% is. I have it currently set roughly in the middle between where it stalls from too lean to the same point for too rich. I am assuming that my WUR pressures are within spec. I had a system pressure of 55psi, cold control pressure of about 30psi @ 68 degrees and a warm pressure of about 50-55psi.

I know of one vacuum leak that I have just fixed last week (vauum advance module), and haven't had much chance to drive it since setting the timing etc. Damn rain!!
__________________
Brendon

80 911SC "Weissach"
77 930 (in pieces)
Old 04-30-2006, 08:24 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Registered User
 
Jim Williams's Avatar
 
Join Date: Feb 2005
Location: Huntsville, AL
Posts: 1,346
Brendon,

55 psi is too low. Your system pressure should be around 72 psi for a normally aspirated engine. This is true for all 911 CIS engines. I think Turbo engines are around 90 - 100 psi.
__________________
Jim
www.jimsbasementworkshop.com
(CIS Primer for the 911)
(73 911T (RS look) coupe)
(Misc. 911 Parts for Sale)
Old 04-30-2006, 09:18 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Mar 2006
Location: wisconsin
Posts: 205
Garage
Thanks

That was a typo - It should have read 75psi (~5.25 bar) for my system pressure.
__________________
Brendon

80 911SC "Weissach"
77 930 (in pieces)
Old 04-30-2006, 09:25 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Registered User
 
Jim Williams's Avatar
 
Join Date: Feb 2005
Location: Huntsville, AL
Posts: 1,346
Brendon,

I found the info on the 112 WUR. The chart is in my Porsche spec book for the 82/83 911SC/Turbo. It is used on the 930/66 Turbo engine, '83 -'86 ROW.

(Brian, you can stop your search for the 112 specs.)

At 10deg C, cold pressure is 1.0 bar

At 40deg C, warm pressure is 2.2 bar.

With full vacuum, control pressure is 3.65 bar, and at full throttle, pressure is 2.9 bar.

All these numbers are with +/- 0.20 bar tolerance.

Your 072 would have 1.7 bar at 10deg C, and 3.3 bar at 40deg C. The 072 WUR has no vacuum input, while the 112 does have one.

Hope this helps.
__________________
Jim
www.jimsbasementworkshop.com
(CIS Primer for the 911)
(73 911T (RS look) coupe)
(Misc. 911 Parts for Sale)

Last edited by Jim Williams; 04-30-2006 at 04:19 PM..
Old 04-30-2006, 04:14 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,423
Garage
Jim, that chart is an addendum to the 930 factory manual ('78/'79) as well.
What I want to know is how a Euro 930 WUR ended up on a 1980 SC. I take it the boost fitting is capped. How long has this WUR been on the SC? Has it been running well until recently? As you can see by Jim's specs the 112 has a cold pressure setting that is more rich than the 072. Your engine must have been tuned to compinsate for that difference. What fuel head is on the SC?
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 04-30-2006, 07:50 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
 
Registered User
 
Join Date: Mar 2006
Location: wisconsin
Posts: 205
Garage
I bought the car about a year and a half ago and it came with the 112 WUR on it. I have all (or at least most) of the service records from day one. I think it had a regulator changed out maybe 7 years ago and a full CIS tune-up at that time; no mention of ever changing the fuel distributor that I can recall.

I always noticed some minor surging only when cold and low speed and didn't think much of it. This spring I put on SSI's and a sport muffler and the problem was much more prevalent. Vacuum (boost) nipple is just open to atmosphere. The number I see on the FD is 0 438 100 077
__________________
Brendon

80 911SC "Weissach"
77 930 (in pieces)
Old 05-01-2006, 02:20 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)
Registered User
 
David's Avatar
 
Join Date: Apr 2002
Location: Houston (Clearlake), TX
Posts: 8,603
Garage
__________________
2014 Cayman S
2011 Cayenne Turbo
1979 930 (475 rwhp at 0.95 bar)
Old 05-01-2006, 02:40 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #20 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 07:46 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.