[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.