O2 sensor in collector of header

[ctk30]

Has anyone had issues with the o2 sensor being a few inches past the merge of the tri-y in the collector?

I’ve read a few things were people recommend having the sensor 12 past the collector into the exhaust but I have a slip joint connection

This is an ls1 with around a 250 duration jones cam, open exhaust into a nascar style boom tube

My thought being that the tri-y and how it functions could give false readings

[77cruiser]

Mine is about 4 inches past the merge.

[ctk30]

[rebelrouser]

I run these style collectors, https://www.summitracing.com/parts/flo-c178238350, with O2 bung just past where the tubes go into the main collector, O2 shows lean at idle, seems to read fine at higher rpm's