Modified my WUR
 

After completing my turbo conversion, I was having tuning issues. We found that my Control pressure was too low, so I decided to make my WUR adjustable, it took maybe an hour taking my time, and shelled out $8, seems to have come out great, I still need to put a pressure gage on it to fine tune it, but after adjusting the Pin up it seems to have leaned it out enough to run right.
Markhttp://forums.pelicanparts.com/uploa...1142865819.jpg http://forums.pelicanparts.com/uploa...1142865836.jpg http://forums.pelicanparts.com/uploa...1142865855.jpg http://forums.pelicanparts.com/uploa...1142865870.jpg http://forums.pelicanparts.com/uploa...1142865889.jpg

Nice one, Tripster.

When you are adjusting the plug, make sure it does not rotate. This may cause the lever arm beneath it to rotate out of position. Some have installed a drift pin between the plug and the housing, by drilling into both, in order to lock the plug in the right orientation. I suppose you could also scribe a line in the plug and just make sure it does not move during adjustment.

I will hold the allen head and adjust with the nut, there shoud be no rotation, correct?

What you might want to do is open it up and make sure the bimetal strip is not touching the sides of the WUR. Then etch or scratch an index mark on the adjustment screw and the top off the housing. Of course, the hot ticket is to machine a key slot on the housing and the shaft, which could be done easily by drilling one more small diameter hole right in the edge of the adjustment pin and the housing and insert a roll pin.

Thanks for the detailed pix.
What year is that WUR from?
Bosch number?

Thanks Ron, Sounds like a great idea, how thick is the area around the Pin? Are you thinking 1/8 hole with dial pin between the pin and housing?

Gunter, the WUR came on my 78 3.3 when I bought it, not sure if it in fact is a 78. The number is as follows. Bosch # 0 438 140 054

Could the last number be a 045?
The correct WUR for '78-'79 is 0 438 140 045
A 3.3 would be a 100mm P/C's conversion?
What cams?

No, it's 054, if you will look at the last picture on the post it is very visable.
Motor is a 78 3.3 Turbo
K27 Turbo
Cams, not sure, can't find a referance to the markings AN- 959
Euro Exhaust
Magnaflow Duel outlet muffler
Heads- I was told have been ported---- I dought it.

Cams?------ Probably Stock
I did call Andial and they said "NOT Andial".http://forums.pelicanparts.com/uploa...1142872125.jpg

O.K. Didn't realize it was a turbo.
Nice!

Tripster,

That drift pin (or roll pin, as Ron called it) could be something like 1/8" dia. The idea is to have it bridge both the plug and the WUR body, locking the plug in place so it does not rotate. This could shoot the arm inside up against the wall of the WUR. If you scribe the location instead, make sure you never rotate the plug.

yeah drift pin...I don't know what I was thinking...a senior moment.

any pics of the unit torn apart so the rest of us can see what's going on inside?
thanks
Bill K

Since this thread has come up again, I want to take the opportunity to thank Tripster for posting his high quality and detailed process for making an adjustable WUR. I did this about ten months ago using a print out of this thread as a guide, and it was a breeze. :)

Perhaps I'm being confused by an oversimplified cross sectional diagram, but what prevents the plug/bolt combination from rising up out of the housing? I see that the washer and nut prevent the plug and bolt from sinking into the housing, but not from coming out. Secondly, how was the plug drilled for the bolt without hopelessly spinning the plug, and reed? Lastly, does anyone have the P/N for the WUR for a 1976 911S? Hershey approaches! Thanks.

There is a lot pf friction between the plug and the WUR casing to prevent the plug from moving within the shaft. Likewise, there is enough friction to prevent the plug from spinning while you drill a hole through it.

That's very similar to how I did mine.

http://forums.pelicanparts.com/uploa...1208309014.jpg

Thanks for the post........it has got me thinking:

I have just run my run my car (79 911SC) on a dyno, the A/F ratio was 12.1 at max power. I think this is too rich, does this modification adjust the cold control pressure or warm control pressure, ie can I lower my control pressure by "knocking in the pin" to lean out the mixture during normal operation?

Thanks, Stu

Both. Knocking the pin in lowers control pressure, both cold and warm. As cold pressure decreases so does warm pressure.