I just went to put on my new GM Extrude Honed Manifold and ran into a small problem. The New Manifold has a housing for a O2 sensor or something but the stock exhaust manifold does not. If I install this manifold I would have an open hole in the manifold.

 

No need to double post, we read your post the first time

 

The extruded manifold is the exact same casting as the stock manifold just different on the inside so it shoiuld be identical

 

Well they arent the same. I guess they changed it with teh 2007 model because My pre cat O2 sensor is below the flange and above the Cat on the downpipe.

 

that's how they all are...

 

Ok here is a picture of Avril's 06 Manifold and downpipe.



On my 2007 where circle 1 is I have a solid metal plate with no hole. and where circle 2 is I have the O2 sensor.

 

No, they're above the flange.

Most custom exhaust and tuning shops sell a plug you can put into an o2 boss.
eBay bung plug ftw!

Edit: I would probably take the easy way out and make a trip to the hardware store, find a bolt with the same threads, measure and cut the bolt, and locktite it in there.

 

This is a picture of mine. Hard to see because its from a phone camera.

 

Thanks Witt. I went to autozone and got something similar to that plug. Put some red locktite on it and it should work just fine. Its a brass plug rather then steel but its rated for temperatures up to 500 degrees.

 

It's going to be hotter than 500 degrees, lol

 

Yeah brass melts at the higher heat range that your manifold will reach. I would definetly look for something steel if you can find it.

 

Yeah but if anything the brass will just expand and fit tighter... These engines even twincharged wouldnt be capable of puting out the heat needed to damage the stability of the brass.

 

ok you guys are filling this hole? my question is what is it there for?

 

Primary o2 sensor. The OP's sensor is located in the b pipe closer to the cat. Earlier models place the sensor in the manifold. The manifold he purchased had the boss located in the manifold already.

 

put wideband in the hole, simple, easy and useful down the road

 

Wideband = money I dont have, wish I could though.

 

why not weld it up? maybe put the plug in and then weld the plug in, i would just weld it up with no plug though

 

mine is not above the flange... mine is directly above the cat

 

They are not all like that.

 

true, mine's probably different because i had the 2 cats and the SAI... i bet that has something to do with it...

 

I recently had my stock DP repalced under warranty because the flex pipe cracked. This really pissed me off becuase a few months earlier I had a bung welded in just before the cat for my o2 sensor for my AEM WB. I have to get the bung re-done now But from what I am reading here, if I get the GMPP extrude Honed Header, I won't have to get the bung done because the there is already a place for the sensor on it? Can someone confirm this??? Thanks guys... FTW!!!

 

Only if you stock primary o2 sensor is in the cat below the flange between the b pipe and manifold. If your primary o2 is threaded into the manifold, then you'll have to have another boss welded again for your UEGO sensor.