WUR....what does it really do?

[T77911S]

you can unplug the vacuum hose to the BOV. the RUF cars didnt even use a BOV.
if it is recirculating it wont be an issue. it recirculates AFTER the AFM

my car was VERY lean on cruise if i set the mixture correct for idle.
it was VERY rich at idle if i set it correct at cruise.

air leak on the low pressure side will make it lean.
air leak on pressure side will make it rich under boost.

do you have an AFR meter and fuel pressure gauge. cant remember

[MD540iT]

Originally Posted by boyt911sc

What are numbers for the other 2 WUR’s you were playing around? Why are you too secretive about sharing these information? How do you expect people to help you if you are withholding critical information? We don’t even know the year and model of the engine. Are you working on a 924?

Tony

secretive?? Im busy, tired, got a lot of things on my plate, and the thing that is supposed to provide some stress relief is adding to my aggravation

I barely have the time and energy to get on the forums.

and I have 3 other cars to work on!

the last 3 of the other WUR that is out is 062

[T77911S]

Originally Posted by MD540iT

Ok I just went and installed the WUR with out the "warm up" parts. initial pressure was 45. started normally. I tried to drop the pressure with the allen but it didnt drop any more. (I was able to raise it however)
SO next I took the bottom half of the WUR off so there was no spring/pin, just what ever it naturally would be at and that was 42 psi. didn't drive it or let it get hot, but might try that next.

c
oh, the allen screw you are messing with.
i assume these WURs have not been modified to be adjustable.
if so, and the allen screw you are adjusting on the bottom is just screwing up the way the WUR works for a vacuum controlled WUR, but i dont see a spec for that pressure.
also, is looks like these WURs do NOT lower the pressure under boost. perhaps these are for early turbos like 76-77. i dont know.

the 054 and 153 WUR are for the later turbos and they have boost enrichment. which BTW is 2.8bar. normal CP is 3.6

the 112 also has boost enrichment.


i also assume you have the cast iron head and that this is a 924????


tony is a great guy.
be patient with him as he is also very busy, is extremely knowledgeable and has been doing this for a very long time. his patients can seem short, but he is good.
remember, both of us can only work with what you TELL us, we are not there.

[T77911S]

ok
some i found out a little bit

the 062 is for a 924
the 916 is a "vacuum" WUR. that is, vacuum raises the CP, no VAC lowers the CP to 2.7bar. which is where it was at. the allen screw you were messing with changes how much vacuum is needed to raise the CP. this one is bad because you are going rich WAY to early in boost, actually BEFORE boost comes in. i think the 054 goes rich around .3 bar boost and most people want to raise THAT up so it go rich later.

find you a 054 or 153 (i dont remember which one is better to be modified ) (of course i have the other one). have it modified to change the pressures but LEAVE THEM ALONE from where they are set when it is modified UNTIL you have everything else working right. then and only then make changes to the pressures to improve performance..not fix it. IE start with it a spec

stop thinking about that heat soak crap and modifying from spec to "fix" it

i deleted most of my last post after searching your WURs

[boyt911sc]

Originally Posted by T77911S

c
oh, the allen screw you are messing with.
i assume these WURs have not been modified to be adjustable.
if so, and the allen screw you are adjusting on the bottom is just screwing up the way the WUR works for a vacuum controlled WUR, but i dont see a spec for that pressure.
also, is looks like these WURs do NOT lower the pressure under boost. perhaps these are for early turbos like 76-77. i dont know.

the 054 and 153 WUR are for the later turbos and they have boost enrichment. which BTW is 2.8bar. normal CP is 3.6

the 112 also has boost enrichment.


i also assume you have the cast iron head and that this is a 924????


tony is a great guy.
be patient with him as he is also very busy, is extremely knowledgeable and has been doing this for a very long time. his patients can seem short, but he is good.
remember, both of us can only work with what you TELL us, we are not there.

Ty,

Were you talking about these WUR’s?



I wish I could work longer hours to catch up with the demand for these WUR’s. For almost a month now, my work schedule is 6:00 AM to 10:00 PM except Tuesday and Thursday for my tennis games (6:00 ~8:00 PM). And don’t forget that I will be 80 years old very shortly and still beating guys younger than my children.

You are right about my patience. Sorry, I’m just a human being with many faults.

Tony

[T77911S]

WOW tony.
yes. 930 WURs


i had to do some searching to find out about the ones he was talking about.....after i had written the previous post.

i need to come up your way and come see you again.
maybe when we have more time to hang out.
i plan on retiring at the end of the year!!

[MD540iT]

well I finally got a chance to to more testing.
first I built an intake pressure tester/smoke tester, couldn't find any leaks (just as I had presumed)

I installed Wur #B and turned the fuel pump on pressure read 85!! despite having done everything to lower the pressure. Car did start however.

Next I installed WUR #C and pressure was in the ball park, adjust it to spec (cold with the heater disconnected)
Started and drove the car, and it was driveable, no longer going lean on cruise. a little rich on take off, and going too rich on boost. But Seems to have made some improvement.

BUT.....then while driving around the neighborhood I must have stopped 20 times to get out and adjust....seeming to make it worse.... trying to find the sweet spot. While I got the cruise ok, was going into the 9's on acceleration, was having a hard time dialing that out.

on a side note, I was surprised to see how much the heating element changes the pressure. I thought the engine heat alone was enough. but as I unplugged the heater to make adjustments I could see the pressure change. and after I was done adjusting, I would have to plug the heater in again and wait almost 2 minutes to and watch the pressure rise.

now i have to go fix my daily :-(

[MD540iT]

Ok well I gave it one more shot and got it "good enough" for the time being, but all this has motivated me more to get the EFI going.

Continuing from last time: I turned the pump on and gave it a couple min to warm up and the pressure was at about 38, with the garage being around 90deg. I gave the Allen (lets call it the "B" adjustment screw) a half turn. got it to about 40. then started the car, and as it warmed the A/F started to climb a bit toward 15, but the idle was a little high, so I turned the idle down a tad and this brought the idle A/F down to 14.7 (which is what im looking for).
Went for a short drive and on easy accel off the line was getting a/f in the low 13 to high 12s and a bit too rich, mid 11s when I gave 1/2 throttle. and dipping into the 9's on boost
Stopped and decided to turn the B screw in a little more about 3/4 turn and got the pressure up a bit around 42, which pushed the (parked/idling car) A/F to 15.4. then I turned the mixture up a bit about a 1/16 of a turn clockwise, bringing back down to 14.7
This seemed to get it in the ball park, still getting mid 10's on boost, I little too rich in my opinion, but I can live with it and get a few mtn drives in before winter. and start working on my other cars.



I think I may have been making too large adjustments and fighting one "over adjustment" with another.

[T77911S]

i dont think you really understand how CIS works or what/how the WUR works.

CIS is a well engineered system that really is extremely simple with one adjustment and you are done. the engineering takes care of the rest.

the reason i say ONE adjustment is that the only one that was designed to be adjusted was the mixture. well two, you have the idle.
not the pressures or anything else you are messing with.

CIS has a range of system pressures and control pressures (both cold and warm) that it is designed to work at.
you can change CP all day long but you will always come back to setting the mixture with the allen (not the one on the WUR). the AFR change from idle to cruise to WOT (not talking turbo at the moment) will always be the same. what WILL change is the RPM at which the three happen. but if you mess up the CP enough you never really will get the idle to lean cruise.

here is why.
im trying to keep this all short as i can
the AFM has three different shapes to it.
a very short idle section
the cruise section which is wider so the sensor plate has less movement for the amount of air coming in to make it leaner.
then the WOT section that is narrower or opens up LESS so that the sensor plate moves more to make it richer.
the sections are designed to change the mixture at certain RPMS. when you change the CP you change WHERE the sensor plate is for a given RPM. lets say idle. then you adjust the mixture screw for a given AFR. lets say14. if you lower the CP, now the sensor plate is higher (into the cruise section) but then you go back and adjust the mixture for the same 14 at idle and you may not get the leaner mixture change.
now the mixture will also richer sooner for WOT. on my 77 that was around 4k (if i remember correctly) but now that you have lowered the CP it may go rich at 3500.
this is just a basic WUR.
then add in vacuum enrichment for NA cars and boost enrichment for turbos. BUT, all this was engineered to work BASED on SPEC settings such as SP and CP.

again, if you are changing the allen screw on the bottom of the WUR you are messing up what was designed in for WOT running. and that does not change HOW rich it goes but WHEN it goes rich.
for a vacuum WUR when the vac drops for two reasons and to a certain amount the CP will drop thus making it richer. it runs richer at WOT and it also gives a quick burst of enrichment when you give it gas. much like an accel pump on a carb. when the vac drops

a boost WUR is just that. once a certain amount of boost is reached the CP drops a certain amount. for the 930 its about .6 bar drop.

a little more on the "one adjustment" thing
these are just made up numbers but this is how CIS is designed.
if you set the mixture to 13.5 at idle once you get to cruise the mixture will go up 1 point to 14.5.
then at WOT it drop 2 points from that to 12.5

if you set the idle to 14.5, cruise will 15.5 and WOT will 13.5
if you set idle to 12.5 cruise will be 13.5 and WOT will be 11.5
do you see the pattern.

you can change the CP but the change in AFR will ALWAYS be the same. you are just changing at what RPM it goes from idle, to cruise, to WOT.

i have tested CP's down to 2.8 and up to 4.5 on my 930 (spec is 3.6) and if i set the idle AFR to the same place the cruise and WOT were always the same AFR.
i have tested the change in AFR on my 2.7 for vacuum enrichment and WOT AFR. same thing.
(i never changed the vaccum setting on my WUR)

you have to put things back to spec. you either need to send one WUR off and have it rebuilt and dont mess with it or you need to set the allen screw back to where it was. i dont think you can do that based on what you seem to be thinking and what you seem to understand.
im not trying to be an A$$ but you are going down a rabbit hole that leads to just chasing your tail.

dont use the CP to set the mixture. its an OPERATING SPEC ONLY use the mixture screw ( i assume you have one on the AFM) to set the mixture. but with the allen screw messed up you still may not get it working right.

all the above is for a factory system. now some WURs can be modified to change some of these things but you really need to what you are doing, why you are doing it and have a need to change it. a lot of people will change the boost enrichment to come in at a higher boost. but you need to put pressure into the WUR to set that correctly.

i have been down all these roads trying to fix my 930 when it had a bad FD all along. no matter what i did it was not going to correct for a bad FD that was extremely lean at cruise. idle and WOT were fine.