Which WUR is better or preferred? 089, 033, 045, others

[PeteKz]

I thought about reviving a previous thread that discussed different WURs https://forums.pelicanparts.com/porsche-911-technical-forum/1114286-cis-troubles-two-problems-related.html, but then thought it might be better to start a new one for future reference.

My 1980 RoW engine (stroked to 3.2 with 10:1 Mahle sport pistons) has the larger heads and intake runners, and older SSI exhaust. It has an 089 WUR. I also have a spare 033 WUR. But I've read about the other WUR numbers too.

I do have to operate in sub freezing to 100+F temperatures. My CSV and TTV and thermo switch work. I have removed the decel valve and AAR and AAV and plumbing, because I have a hand throttle in my 1973 to hold the idle speed up when cold, and not having that stuff in the way makes access to the TOD much easier. I have a AEM AFR installed. Idle AFR is about 14, it goes up to 15-ish when initially applying throttle and 15.5+ at highway cruise. At full throttle, it eventually goes into the 12 range at high RPM. I would like for it to go into the 12 range at full throttle at any RPM, not just at full throttle and high RPM, if that's possible.

Question for the CIS experts: If I wanted to choose the "best" WUR for my engine, should I stay with the 089 in it now? Or should I look at other possibilities? What are the significant differences in how they work? I have not modified my 089 to make it adjustable, but I like the idea of being able to externally adjust it.

Other considerations or warnings?

Thanks in advance.

[icarp]

You know i have an opinion

ian

[Paulporsche]

Do you have lambda control?

I do not in my car, which has a 1980 engine enlarged to 3.2 w/ 98mm pistons. Since I have no lambda control I use the 045 WUR, which allows extra enrichment via the lower chamber for higher revs.

If you have lambda, this provides the enrichment, rather than vacuum on the lower chamber.

BTW all WURs are adjustable, of course. The usual adjustment feature allows for ease of setting the Cold control pressure.

[PeteKz]

No lambda, it's a 1980 RoW engine.

Ian: Well? Share it! I'm looking at all options.

[RarlyL8]

A non-Lambda WUR with a vacuum port will allow for enrichment at higher RPM. If you are leaning out on top the fuel distributor can be adjusted for more flow.

[pmax]

Porsche added enrichment based on the throttle switch to the later SCs.

https://www.jimsbasementworkshop.com/CIS/pages/lambda/Mode%203%20TT.html
From Jim William's invaluable website

[PeteKz]

RarlyL8: Thanks for the reply. My 089 WUR does provide vacuum enrichment.

Pmax: Yes, the lambda-equipped SCs have enrichment based on the throttle switch because those WURs do not provide vacuum/load enrichment, due to the operation of the lambda system during part throttle. I don't want to install the later SC lambda system, instead I want to use a WUR that provides the "best" results for my non-lambda engine (however one defines "best").

I'm hoping Tony will lend his expertise here...

[Nditiz1]

I dont know WURs only how to test them with gauges. I have an 089 on my 82 US engine. Actually the entire CIS is a Euro one. So I'm running large intake runners on small port heads. Yeah a mismatch there and probably a little loss, but I have no lambda electronics to mess with. Car runs great in all weather. Just use the 089 and you'll be fine OR go no WUR.

[boyt911sc]

Peter,

What fuel distributor do you have on your motor? What is your WCP (with & w/o vacuum applied)? Thanks.

Tony

[PeteKz]

Tony, thanks for the reply. My FD ID plate is hard to read, but I think it's 148153 041, I haven't measured WCP yet. I lost the adaptor to the CP line sometime during my last move 3 years ago. I bought some small brass plumbing parts at Ace Hardware today, and tomorrow I'll try to make an adaptor out of that, plus the extra CP line I have. It may be a kluge, but I'll make something work. Then I can measure it.

[PeteKz]

It appears my 089 WUR has an internal problem. MY SP is 71psi, but my cold CP is 68psi. it should be much lower than that. So, it looks like I'll have to pull it apart to inspect it. The resistance across the WUR plug is 31 ohms. The resistance of my spare 033 WUR is 22 ohms.

Tony: I don't think that the operating pressures of my WUR are relevant to my question of this thread. My question is: if you wanted to put together the best components for the ultimate CIS, what WUR would you choose and why?

[PeteKz]

I opened up the 089 WUR, and while I was at it, I also opened the 033, side by side to observe the differences, which are significant. As several others have hinted, the vacuum works oppositely on these two WURs. That is, the vacuum pulls up on the regulator valve on the 089 when it is applied to the SIDE vacuum fitting, and it pulls up on the 033 when attached to the TOP fitting. I disassembled the upper chambers including the regulator valve itself, with the thin stainless steel disc inside, cleaned it all with carb cleaner, then gave everything inside a spray of WD40 to preserve surfaces, and put it back together. I did not completely disassemble the lower chamber of the 089, because the diaphragm in the bottom did not want to easily release, so I peeled up the side of the diaphragm and peeked in side, didn't see anything amiss, and put it back together. Separating the plates of the bottom chamber in the 033 was more challenging, so I let it alone. It wasn't leaking before I took it apart, and I didn't want to break something that wasn't broken.

The SP of the 089 remains unchanged at 71. the CP started out at 30, then rose to 54 (not running, connector plugged in, without pulling vacuum). Better starting pressure, the the final pressure is still too high. Arggghh. More futzing with it. I will also substitute the 033 and see what numbers I get from it. I might try to run that one instead.

Back to the original question: If you were building the best CIS system you could, which WUR would you use and why? (No point in me futzing with the 089, if another version is better for my purposes)

[snbush67]

Go to about 12:30 minutes.

The article on making the WUR adjustable is by Jay Pineau, Ark-La-Tex Region, PCA, in Volume VII, pages 116-117 of Up-Fixin.

https://forums.pelicanparts.com/porsche-911-technical-forum/218814-made-adjustable-wur-step-step-got-pics.html

https://www.pelicanparts.com/techarticles/911_warmup_reg/911_warmup_reg.htm

[PeteKz]

snbush67: Thanks for the links. I already saw the video with Ian Carpenter, and I have chatted with him a number of times. His approach was to bypass the WUR and go to manual control of CP. I'm also keeping that option in the back of my mind.

But I would like to get a WUR set up so that it gives me good cold starts, efficient warm running at part throttle and quick enrichment at full throttle at any RPM. The two WURs (with vacuum ports) I am familiar with tend to not give you enrichment when you put your foot down, but wait until the RPM gets high. Kind of odd, IMO, but that's how they seem to work.

I have an AEM AFR installed, so I am actively monitoring AFR as I drive, and to test/observe the function of the WUR.

Anyway, I think I'll mod my 089 WUR and see what I can do with that.

[panama911]

Originally Posted by PeteKz

The two WURs (with vacuum ports) I am familiar with tend to not give you enrichment when you put your foot down, but wait until the RPM gets high. Kind of odd, IMO, but that's how they seem to work.

Pete,
As I see it, those WURs lean out/raise pressure whenever you have manifold vacuum, that is at idle and part load.. this is what provides enrichment when vacuum decreases at load/WOT. Now, when you floor the pedal at low rpm, vacuum doesn't drop to zero immediately...
A device that would bleed off pressure whenever you go WOT could be the early TPR (Throttle Position Regulator) hooked up parallel to the WUR, in your case with a modified cam so it would bleed off to say 2.3-2.6 Bar only and always when throttle is wide open (and not also at idle like the original early TPR)...

BUT: Why would you want a behaviour like this? I guess it would only lead to worse fuel economy dumping extra fuel at low RPMs when engine load / needed power would also be rather low?

[PeteKz]

I'm aware of the TPR too. I'm pretty sure my original 1973.5 CIS engine had one.

What I'm looking for is a WUR/CPR that enriches under load (low vacuum), and leans out at cruise, which is what later electronic fuel injection systems do. Since I installed my AFR a month ago, I watch it regularly when I cruise or accelerate. I have noticed that the WUR gives roughly the opposite of the behavior I expect most of the time. When I put my foot down, first it goes lean before enriching, and then only a little bit.

To give some actual examples: Last night I was cruising on the I-5, and noting the AFRs, because I'm going to swap to the 033 today or tomorrow, and run the same loop, and compare the behavior. The AFR was in the low 14 range at cruise between 60 and 80 MPH. When I accelerated, it would jump up to the 15+ range for a second or so, then drop back to the mid 14 range. When I took my foot off the gas, the AFR would drop to the high12 range briefly, then rise to the mid-13 range, then gradually up into the 14 range as the car slowed down. Yes, the hoses are hooked up correctly, and the thermo switch is open after 10 seconds of warmup, etc.

Add to the puzzle: At idle, fully warmed up, it's showing about 13:1, which is much richer than I expect.

Whereas, what I expect to happen is that it should be cruising at mid 15 or a bit higher, and when I accelerate, it should drop into the high 12 range. When I back off the throttle, it should rise to the 15-16 range, and when I return to cruise, it should stabilize in the low to mid 15 range. And I expect it to idle in the high 14 to 15 range.

Anyway, I'll continue to play with it and post my results here. I also need to fiddle with the CO screw some more and see what results I get after re-setting the idle AFR to 14.5 or so ( I did previously set it to that value)

[panama911]

Well... forget about an extra device for WOT-enrichment, I don't think you need that.

Your symptoms sound like you are running with part throttle all the time - also, accelerating between 60 and 80 mph which translates to only 100-130 km/h doesn't really present a huge load?

2 Questions arise:
- Are you sure your throttle opens all the way?
- Did you check that the pressures of your WUR are in spec, with and without vacuum?

[boyt911sc]

Peter,

Could you double check the Bosch ID # of your FD? The ID number you posted (1 481 153 041) look strange to me because it should look like 0 438 100 XYZ format. Thanks.

Tony

[PeteKz]

That was the serial number stamped on the ID tag. I had to look very closely to make out the part number (dumb idea to put gold print on silver background). The part number is 438 100 031. It is from a 1980 RoW engine, and the WUR is a 089. And I have a spare 033 that I just installed to see how it behaves. More on that later.

panama911: Thanks for the response. Yes, the throttle plate opens all the way. It would not make a difference in how the WUR responds because the manifold vacuum falls to near atmospheric with more than about 1/4 throttle at lower to medium RPMs. I know the 089 WUR is out of spec, which is why I am testing the 033 WUR.

[boyt911sc]

Peter,

Could you post the WCP with and without vacuum for both WUR’s (-033 & -089)? How much enrichment they provide? The numbers will tell you whether the enrichment is good or low.

Tony