hey i just got a hks downpipe for my car and my friend was talking about a part i need called o 2 housing can any explain to me what that is

 

You need to have an o2 sensor bung welded onto your DP if it doesn't already have one. Any muffler or exhaust shop should be able to do this.

 

o ok yes there is a spot i think were it needs to be put in

 

Pretty much anywhere on the downpipe.. Just pick a spot.. drill a hole... and weld up a bung. Can't remember where you can get one.. .. but should be able to assertain the threads from the old o2 sensor.

 

o there is already a spot for one i belive but i talked to him and he still says i need new o 2 houseing not a sensor

 

Yeah.. thats the "bung" we're talking about. Its just a circular threaded piece you weld on so you can screw in an o2 sensor. If thats already there, then just screw in your o2 sensor... because if there's already a hole.. you have a major exhaust leak.