I do not have an 02 sensor in my header, so I have a big hole there, and I'd like to fix it because my car sounds like crap. So, in order to do that, I'm going to put a bolt there, but I need to know the diameter. If anyone knows this please let me know! Thanks!

 

dont put a bolt in there, youll disrubt exhaust flow. unless you get one and cut off all the excess you dont need so it doesnt protrude into the pipe. get down there and take a tape measure to it and buy that size and the a few sizes above and below to make sure you get the right one.

 

Whats the best way to cut it?

 

a saw, how else would u cut it? it doesnt need to b a smooth cut...y dont u put the o2 sensor back in?

 

omg, your cars going to run like crap after a couple weeks...You need that O2 Sensor man.

 

which o2 sensor are we talking about here? the first one or the 2nd one(obd2 cars). if you went obd1 and needed to fill the 2nd o2 hole thats fine. but your car will run like shit without an o2 sensor.

 

I'm obd1, so I've got a sensor already...I think its by where my cat was. I just have a huge exhaust leak (in many places, not actually relating to the exhuast, but from putting an aftermarket header on). The size I found on honda-tech said something like 1.8cm x 150 and I was telling my bf about it and he said that was way too big...any thoughts on this?

 

try it out and c...still dont get how ur running without an o2 sensor...

 

you need to have an o2 sensor, it controls the fuel/air ratio of your car. without it, youll have the CEL and your car wont run right.

but if you will, its an M18 1.5. check harware stores and muffler shops.

 

ugh im so confused >.< so u have a hole in ur header where the o2 sensor is and u dont have one there? so u want to put a screw in there to fill the hole? dont u need the sensor in that spot?