Tungsten Posted April 14, 2011 Share Posted April 14, 2011 (edited) Here's the story... My midpipe, one with the o2 bunghole, has gone to crap and now looks like swiss cheese. I have the Doug Thorley headers with a 2.25" collector output. I want to know three things: 1. What is the thread pitch of the o2 bung or what would be a good screw in thingy into a custom pipe? 2. Is it possible to buy a test pipe to make a straight pipe from the collector to the catalytic converter? 3. Is there an already made 2.25" test pipe that will fit the stock oxygen sensor? I'm asking this because I can't find anyone around here that will make me a stainless steel pipe with flanges and an o2 bung. EDIT 1: The pipe has to be ~26 inches long. EDIT 2: Something like this but longer so it clears the transfer case (but it might work, need additional measuring): http://www.genkituning.com/1993-1997-Nissan-Altima-Test-Pipe-Converter-p/1-excs-na93.htm EDIT 3: Some photos for reference and proof that a straight test pipe can work (I might have a few more photos later): Edited April 20, 2011 by Tungsten Link to comment Share on other sites More sharing options...
adamzan Posted April 14, 2011 Share Posted April 14, 2011 Can you not just order some pipe / flanges off the net and have a shop bend and weld and assemble? Link to comment Share on other sites More sharing options...
Tungsten Posted April 14, 2011 Author Share Posted April 14, 2011 (edited) Can you not just order some pipe / flanges off the net and have a shop bend and weld and assemble? It turns out that with my setup there is not even a need to bend. I just need flanges and a stainless steel pipe. I have no idea how much welding I can get done around here, no one seems to want to touch stainless steel and the test pipe already has the flanges professionally welded on. The only thing I'm not sure of right now is which o2 bung to screw in there. Edited April 15, 2011 by Tungsten Link to comment Share on other sites More sharing options...
sewebster Posted April 14, 2011 Share Posted April 14, 2011 Googling seems to suggest that it is very likely M18x1.5 but no guarantees from me. Link to comment Share on other sites More sharing options...
Tungsten Posted April 14, 2011 Author Share Posted April 14, 2011 first post updated and can someone double check M18x1.5 Link to comment Share on other sites More sharing options...
Precise1 Posted April 15, 2011 Share Posted April 15, 2011 No one will weld a patch over that?? Let me go look for my spare O2 in the garage, I think I saw it yesterday... B Link to comment Share on other sites More sharing options...
Precise1 Posted April 15, 2011 Share Posted April 15, 2011 Damn, you are lucky my buddy just bought a WD21 and needed some parts, I found it first try. Where are one of my 10 calipers?? Where is the thread gauge?? *grumble* It's a short thread, but I'm sure it is an M18x1.5. B Link to comment Share on other sites More sharing options...
unccpathfinder Posted April 15, 2011 Share Posted April 15, 2011 Not gonna have a lot of backpressure...I've been running no pipe behind the cat for 8 months Link to comment Share on other sites More sharing options...
unccpathfinder Posted April 15, 2011 Share Posted April 15, 2011 And hell b I don't even think they they need a patch...I could weld that up with no added material Link to comment Share on other sites More sharing options...
Tungsten Posted April 15, 2011 Author Share Posted April 15, 2011 i want to just replace the midpipe with straight stainless tubing in 2.25 Link to comment Share on other sites More sharing options...
Kingman Posted April 15, 2011 Share Posted April 15, 2011 So... do it. Link to comment Share on other sites More sharing options...
Tungsten Posted April 15, 2011 Author Share Posted April 15, 2011 yep, i will, i found out a place that will build me a pipe also MY1PATH said to use weld-in flanges so i'll get those Link to comment Share on other sites More sharing options...
Tungsten Posted April 20, 2011 Author Share Posted April 20, 2011 (edited) some more pics of currently routed exhaust, you can see how the cat needs a slight angle or may be too far from the midpipe Edited April 20, 2011 by Tungsten Link to comment Share on other sites More sharing options...
Tungsten Posted April 20, 2011 Author Share Posted April 20, 2011 o2 bung and flanges are here Link to comment Share on other sites More sharing options...
adamzan Posted April 20, 2011 Share Posted April 20, 2011 Where is the cover for the end of your transmission Link to comment Share on other sites More sharing options...
Tungsten Posted April 21, 2011 Author Share Posted April 21, 2011 someone failed, i have to find one asap Link to comment Share on other sites More sharing options...
Precise1 Posted April 21, 2011 Share Posted April 21, 2011 You need calipers... B Link to comment Share on other sites More sharing options...
Tungsten Posted April 22, 2011 Author Share Posted April 22, 2011 You need calipers... B I have them, I like my ruler more. From the looks of this, I need to get a 2.50" pipe put together with 2.50" flanges. Also, the O2 bung is M12x1.5 and NOT M18x1.5 as I was told. M12x1.5 bung on the left vs the M18x1.5 bung on the right Looks like I will be sending EVERYTHING back! Link to comment Share on other sites More sharing options...
Precise1 Posted April 22, 2011 Share Posted April 22, 2011 I truly apologize, the O2 sensor for my 95 is M18x1.5. I did not think to check that they changed the thread size between the years. Did you check or specify?? Picture of a 91 O2 sensor. http://www.rockauto.com/catalog/moreinfo.php?pk=481678 Picture of a 95 O2 sensor http://www.rockauto.com/catalog/moreinfo.php?pk=481588 Hard to tell and pictures aren't always accurate, but different part numbers... B Link to comment Share on other sites More sharing options...
Tungsten Posted April 22, 2011 Author Share Posted April 22, 2011 (edited) I checked and got different answers on the sizes. So I decided to get a M18 and see if that fits. I believe that the late models like 94-95 have different sensors because that's when the ECU has changed. It's not a big deal just a little annoying to have to order another bung. BTW, you USE a 17mm wrench to extract the M12x1.5 sensor. So there's one bonus of having the smaller sensor, no need to have a special oxygen sensor wrench. Although using a bigger wrench to extract these is much better than having to use a smaller one. Edited April 22, 2011 by Tungsten Link to comment Share on other sites More sharing options...
adamzan Posted April 22, 2011 Share Posted April 22, 2011 All the "special wrench" is, is a socket with the side cut out for the wires to go through. It doesn't make a difference what size the 02 is the socket makes it easier than using a wrench... Link to comment Share on other sites More sharing options...
sewebster Posted April 22, 2011 Share Posted April 22, 2011 (edited) All the "special wrench" is, is a socket with the side cut out for the wires to go through. It doesn't make a difference what size the 02 is the socket makes it easier than using a wrench... Also, if you're extracting a dead sensor you can just cut the connector off the end and put a regular (long) socket on (thread the wires through). EDIT: sorry, that makes no sense, what I think I meant to say is you can thread the wires through the closed end of a wrench. If you cut the wires entirely off then you might get a long socket on it. Edited April 22, 2011 by sewebster Link to comment Share on other sites More sharing options...
Kingman Posted April 22, 2011 Share Posted April 22, 2011 I believe the 22MM oxygen sensor is the Titania type, and the 17MM is Zirconium. Nissan has been switching sizes/types around since they first made the Z31 depending on the year and engine type. There's really no rhyme or reason to it. I do know that each computer is designed to run a certain type of sensor, and mixing them around can cause some damage. The sensor on my '88 is 17MM. Link to comment Share on other sites More sharing options...
Tungsten Posted May 7, 2011 Author Share Posted May 7, 2011 OH HELL YES, first section made!!!! Hey, it's almost straight... I guess this should be renamed to custom "home-made" 2.5" exhaust building thread. Link to comment Share on other sites More sharing options...
nunya Posted May 7, 2011 Share Posted May 7, 2011 I'm straiter than that thing... Link to comment Share on other sites More sharing options...
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