Certified Muffler downpipe, o2 sensor bung size question

  • #1

    Certified Muffler downpipe, o2 sensor bung size question

    Those of you who had a bung welded onto your downpipe, do you recall what size it was.
    It's much larger than the M18x1.5 that is typical, this is more like a m22 size. I did call CM
    and he was like…i dunno, whatever is normal i guess. The guy was no help at all.

    I have tools to measure the thread pitch and can use calipers to measure the ID and with
    those two measurements should be able to find something at McMaster-Carr, but i thought
    i'd ask here just in case. Auto parts place and ACE hardware were strike outs.
    Althouth a 15/16 flare fitting for a gas line did thread in loosely at ACE. I'm just looking for a plug as of now.


    84 AE/Shiro #683/Shiro #820/84 Turbo
  • #2
    I didn't have an O2 bung welded to the downpipe - used the original in the turbo elbow. But I can attest to the eccentricity of the guy at CM. He kept asking what axle-back exhaust I was pairing with the downpipe/test pipe combo I had ordered and then started ranting on how people keep copying his exhaust components. Bit of a nutjob.
    '86 300ZXT GLL
    '78 Datsun 280Z BP
    '11 Saab 9-3 Aero XWD
  • #3
    are you sure it is not an AIV port
    Hmmm, Whats next?
    Full Size Bronco, smashing shit.

    84ZXT
  • #4
    You got it,. Shromy.

    It is an AIV port.

    It's M24X1.5. (same thread pitch as a Toureg oil pan fitting, Dorman PN 65415, for reference)

    I dug up the invoice from 2013 and i forgot i indeed ordered it with the AIV fitting. The AIV system is now deleted, i'm a dumbass.

    Would it be easier to grind off the fitting flush and weld in a M18 bung than try to find a reducing bushing to M18 from M24x1.5.
    That is a unicorn fitting.

    Or, does the sensor need to be in the exhaust stream, i mean if i could tap a M24x1.5 plug for M18, could the wideband be adjacent to the exhaust flow and still be accurate.
    Last edited by Z_Karma; 09-13-2016, 12:53 PM.


    84 AE/Shiro #683/Shiro #820/84 Turbo
  • #5
    I like to shove the invoices in a file cabinet, never to look at them again

    I've got a mild steel 18x1.25 bung from the Innovate wideband kit P/N 3839 that i'll never use - it's the tall bung, not sure if that makes a difference? cover shipping and it's yours

    from what i've read ideal WBo2 placement is 18-24" downstream, with at least the same length behind it.You'd probably be better cutting away and welding in a plate and bung over the flub-up
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  • #6
    Bung usually comes with the wideband.
    Cha iro

    enjoy building it yourself.
    if it fails, fuck it.
    at least you gave it a whirl.
  • #7
    Originally posted by 88sinZ View Post
    I like to shove the invoices in a file cabinet, never to look at them again

    I've got a mild steel 18x1.25 bung from the Innovate wideband kit P/N 3839 that i'll never use - it's the tall bung, not sure if that makes a difference? cover shipping and it's yours

    from what i've read ideal WBo2 placement is 18-24" downstream, with at least the same length behind it.You'd probably be better cutting away and welding in a plate and bung over the flub-up
    I'll take it man, thanks!

    Can you shoot me an email to [email protected]? I can't PM until i clean out 446 messages or something from my messages folder, cleaned out a bunch but the number isn't going down.


    84 AE/Shiro #683/Shiro #820/84 Turbo