Could anyone tell me what the thread size of the secondary o2 sensor is or where I could find out? Ive been trying to find out for a while so I can get it drilled in my cat replacement pipe by the manufacturer. Ive got a Prelude 2.2 Si Vtec (93) H22A

 

Hmm, does your car have a secondary o2 sensor? I thought OBD1 cars only had one oxygen sensor.

Anyway, I looked in my Integra Helms manual and it doesn't have the thread sizes listed there.

I'll move this to the Prelude forum since that's more applicable to your car.

 

Ive been searching the net and thats all I can think it is. Theres a sensor/wire that goes before the cat and then theres one actualy on the cat at the back. Ive got a cat replacement pipe but no hole for it to go into. The manufacture said theyd put it in but I need the thread size (this is a secondary o2 sensor isnt it?). Please help Ive been trying to sort this out for over a montha nd dont know whoi to ask as its an import

 

M18x1.5