I've searched the DIY Prom board and haven't found a definitive answer (at least nothing I consider definitive) as to where is the best place to put the WB O2 sensor, where is an acceptible compromise, and where to never consider putting it.

I'm thinking somewhere in the Y pipe after the junction and ahead of the cat but is that too far away?

 

What do you call definitive?.

If you runnning a cat, then it has to be infront of that, since the Cat effects the exhaust gas chemistry.
The warmer the exhaust gas is getting to it the less it's heater has to work.
If you want an average of both banks, then the location has to reflect that.
You need for the sensor to be mounted so that condensation doesn't accumulate in it.
If you talking about a high PSI turbo application, you want it post turbo.

 

In my case it's a NA engine with no plans for N2O.

At the risk of being a smart a** I mean a definite answer to the question of where is the best place for a single WB O2 sensor, along with what is an acceptible comprimise. An answer that doesn't include "I'm guessing" or "I think it's supposed to be" or the like.

To me the best comprimise with a single sensor seems to be in the Y pipe but I'm sure it's just that...a comprimise. Add to that the fact that I still consider myself an EFI newbie in search of answers to questions that no one else seems to ask (of course I'm an AMC guy at heart which makes me a little weird anyway).