Non-permanent mechanical rear O2 CEL fix

[Macabre]

I have an '04 so the electric fix hasn't been worked out yet, and since this is slightly new ground I didn't want to weld on my new downpipe in case this fix didn't work, so I made a "screw-in" O2 sensor extension. I was hoping to be able to do this without any welding at all, but I couldn't find pieces with the ride threads . If anyone knows an online shop that carries a lot of M18x1.5 pipe fittings, please post it here! I got the elbow from McMaster-Carr (it's M18x1.5 on one end, compression fitting on the end that I welded). The O2 bung on the other end I got from speedshop.org for $10. $25 in parts all together (yes, that little steel elbow was $15!). The pipe I just had sitting in my garage but it's a 1" OD steel tube from home depot, don't remember what I paid; I've been using it as my breaker bar extension. Now I have a slightly shorter breaker bar extension. Anyways, pics:







I'll report back if I ever get a CEL.

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[VetteVert]

Exactly what I was wanting to do. Hoping to be able to do it without the weld....we'll see

thanks,

VV

[03WRXMA]

Looks like the Godspeed DP, except their DP had a piece small piece of cat in it.


-Dave

[KanosWRX]

Nice, someone should sell these, a lot better then the mil eliminator splicing that is needed. I am lucky though, got a scoobysport catless dp and prodrive catless midpipe and sti catless uppipe, and still no CEL (knock on wood)

[mexicanpizza]

At $50 a pop for about $2 worth of pipe...someone would make a killing. I regret cutting up my O2 sensor...but you gotta do what you gotta do.

Let us know how that works.

[vile]

this is why i luv this board, so cutting edge, so innovative

me thinks a catless dp is in the future

now, how long does that pipe have to go back? ur's looks like it's extended bout 4" back, can it be like 1" or 2"?

[Macabre]

One of the downpipe manufacturers, I don't remember who, sells their pipe with an O2 extension that only sticks out about 2". I think as long as you get it out of direct exhaust flow you should be fine.

FWIW, no CELs yet..

[nhluhr]

i'm not quite clear why this extension eliminates CELs... can somebody elaborate?

[Macabre]

Not me.. I'm just a follower with an adaptation

However it has been suggested that it has to do with keeping the temperature a little cooler than optimal operating temperature for the sensor, which results in readings which appear similar to those that would result from having the cat in place. It may also have to do with certain types of gasses collecting in the extension. Either way, it seems to work, although I need more time with it on my car to determine whether it works as well on '04s or not.

[vile]

Originally posted by nhluhr
i'm not quite clear why this extension eliminates CELs... can somebody elaborate?

Originally posted by Austin
O2 sensors need heat to generate an accurate voltage. The colder they are, the lower the voltage generated. The rear o2 sensor (per the tech manual) is designed for 300-400C temps. Fixes like this work because they allow the o2 sensor to still respond to the exhaust, but at a cooler/lower level.

[nhluhr]

so with cats removed, more heat is hitting the O2 sensor, so moving the O2 sensor to this little extension reduces the heat it sees and fools it just enough?

[fatray]

My splice in CEL fix never worked, still always got a MIL for the reat 02 sensor all the time.

[TopKatz]

You have a part number ont he 90deg elbow? Having a hard time finding a metric one.

[Macabre]

5269K385

[TopKatz]

you rock bro.....

[WRXncrew]

I've found a place that carries every kind of pipe fitting you can think of.

Are these NPT, NPTF, BSPT, BSPP, SAE UN/UNF, or Metric?

I'm thinking it's metric so get a 2" nipple thats M18x1.5 on one end and F18x1.5 on the other end right?

[blaznasn]

whats the place?

[WRXncrew]

If you search around you can find them... they don't make an exact part. You have to combine the fittings to get a male M18x1.5 to female M18x1.5 extension where the mid-connection might be NPT.

At www.mcmaster.com this part is what I found...
4936K159

[jamesohoh7]

Originally posted by WRXncrew
If you search around you can find them... they don't make an exact part. You have to combine the fittings to get a male M18x1.5 to female M18x1.5 extension where the mid-connection might be NPT.

At www.mcmaster.com this part is what I found...
4936K159

For those of us (o.k. just me) that are incapable of deciphering the ins and outs of pipe-fitting (ha!, c'mon.. I know there's some good jokes there, but I'll stay on track ) ... please explain your complete setup to me... or list the part numbers. I can order parts using their numbers like a demon, but I'm definitely incapable of figuring out why NPT 1/4" is so friggin huge compared to something like a 1/4" compression fitting (if I even have those terms right).

"I am just a caveman, and your modern world -confuses- and _frightens_ me... I do not understand 'enn-pee-tee'..." (apologies to Phil Hartman)

If it helps, pretend I'm about 5 years old, use crayons in bold, bright colors, I PROMISE I do not care if you have to talk to me slowly and deliberately to make it clear.... I have an '04 WRX and am anxiously awaiting the advent of "the fix" (whatever it may be) to allow me to run a Bosal DP w/out getting a CEL.

I'm exploring the Cobb thing, but the $$-thing is the issue right now. I want their Stage 2, so I gotta do the DP-thing first anyway... then, I'll save up for the Stage 2 --> meantime, I want the fix if possible.

Thanks mucho in advance, me and thousands of '04 owners anxiously await!, palms sweaty with anticipation (or maybe I forgot to pay the electric bill and my AC has shut off!... nope, computer still working... must be anticipation )

Well, hope that made some folks laugh, but I really do want the info if possible,

-James

[WRXncrew]

I found them at Flat4Engineering then click on Products, then Turbo, then UP/DOWN pipes. You'll see the "PDM O2 SENSOR BUNG EXTENSION" selling for $22.42 it's not cheaper than the electronic fix, but it will thread into the current bung holio

I checked with them, spoke to 'Joe' and he said they are having the machine shop make more.

[s_nold]

is this just for the downpipe? or can it be used for the up-pipe as well? if it is being used for the up-pipe, what are the thoughts on turbulance?
What is the best fix for the up-pipe?

thanks,
Stephen

[VetteVert]

FWIW, my bolt in (no welding) bung extension cost $8. No CEL yet, but only 500 miles so far.

VV

[TopKatz]

If your aftermarket uppipe has a bung, use it.... if not use te resistor fix

[spankaveli]

Originally posted by VetteVert
FWIW, my bolt in (no welding) bung extension cost $8. No CEL yet, but only 500 miles so far.

VV

can you post the part numbers and where you got the parts?

[VetteVert]

Don't have the part numbers with me. It is a package of 2 spark plug arresters (sp?). They are the "Help!" brand in the red blister packs. I seem them at all of the crappy parts stores (autozone, pep boys, advance, etc.). They are almost sealed on one end so I had to drill it out. It was also tapered down a little too small inside, so I slowly went up in size (up to 1/2" I think, will check) on the drill bit until I was satisfied. I bolted both together and into my down pipe. Then installed O2 sensor.

VV

Originally posted by spankaveli
can you post the part numbers and where you got the parts?