I used water pipe and electrical conduit parts :D

[xci.ed6]

So stock O2 sensor thread:
18mm = 0.708"
1.5mm = 0.059" (~16tpi)

So I used 3/8" pipe parts, 3/8" is inside diameter of the pipe, so you get 5/8" thread:
5/8" = 0.625" (15.875mm)
14tpi = 0.071" (1.803mm)

DAMN CLOSE!!!

So with a bit of work:

That's a 3/8" water street elbow, with an electrical conduit nut to seal it. Into an 02 sensor adapter (ebay) and then the stock sensor.

So far, 2 days in, NO CEL / MIL!!!

I did this because the stock sensor wouldn't fit with the 2.5" exhaust I installed.

 

[james'99]

That's awesome! Haha! I don't think you will get a CEL.

That said, I don't think you would get a P0420. You may get a slow response code if anything.

 

[RedRyder]

Now that's a defouler.

 

[xci.ed6]

Still no MIL!

Bumped up because this came up in another thread.

The street elbow male end fit the female hole threads fine, threaded right in. The sensor adapter male threads need rethreaded to fit the famale street elbow threads.

I had the die (tool to cut threads) so it cost me like 5minutes of work. The die would have been $$$, but I already had it. If you don't, you can always use more tools! I only have like 2000lbs in tools, that has been ~$90k, but I always need more!