I was wondering if anyone knew how far down the downpipe i could weld my wideband o2 bung and keep accuracy but reduce heat. And i do have the heatsink extender.

 

Mine is at the 11 oclock position near the front of the "test pipe" replacing my main converter, and seems quite accurate at that position. I have no way of comparing my readings with another device to validate, but they are always in the range you would expect. I recently detected a vacuum leak, which the wide band made very obvious, especially around 2000 RPM (readings went from mid 12's to mid 14's).


Edit: The car's an '87 TII

 

36" from the exhaust port. If you put it much closer you are risking burning out the o2 sensor due to the heat of a rotary