In preparation for my new catless performance exhaust (that BTW will be used for track use only) i am trying to figure out what to do to keep the CEL off.

I have found everything from o2 sensors, adjustable o2 sensors, and o2 spacers.

Does anyone have any experience or conclusive advice as to which will work for sure on the SRT6?

 

The o2 sensors are used to control the fuel loop and I wonder if you want to delete them. How would the engine know if it is rich or lean?

I would like to know if there is a reason that the o2 sensors are an inconvience to you? I believe that the rears can be deleted without errors coming up. I would not think that they cause an obstruction worth measuring.

Others may have chrisper answers though, gotta love the forum.

Woody

 

The rear cats can be deleted but what about the o2 sensors that are after the first set of cats. I figured the first set of o2 sensors are the ones that monitored the rich/lean/etc so of obviously i wont touch those.

I want to run no front or rear cats with no CEL.

 

240, It sounds like you are planning on keeping the front O2 sensors. If so, that should be all you need. I believe that is what Woody was saying also. Taking out the back O2 sensors and all the CATs should not affect the system functions, just better air flow. Good Luck.

MikeR

 

Do you plan to use race gas with no cats?

 

Hey cruzin, do you plan on rooting for a real team like the PATS this year!!!!!

Hijack... complete.... stealers... trash... terminated..

 

Never... Good to see you made it. I left 2 other posts for you and nothing. Thought I lost you in the summer. LOL.

 

Removing (all) the cats will most definitely trigger a CEL (speaking from experience). Remove all of your cats (if you want) then use O2 spacers on the back O2 sensors only. They work great; no CEL. The ECU only uses the rear sensors for monitoring pollution control. I have used them on my C32 with no problems what so ever (mine were even home made. Google search it; you'll find what you need).

 

Thanks Eleventeen, thats exactly what i was hoping for. Can i probe your brain further?

It appears from all the pics of o2 spacers is just a way to move the o2 probe back from the exhaust gases flowing through the pipe. Seems i could just weld 2 or 3 o2 bungs together then plug it in for the same effect, correct?

I did google it as per your recommendation and it seems that there is a "sweet spot" as far as the length and open area of the spacer. Can you give me more details like do i need to make sure its a certain length. What made your c32 happy?

And just to add to the content of this thread my searches also turned up Autozone Help! 42002(sparkplug antifowler) $3.70 ea. Appearantly this is the same thing as an o2 spacer. In all honesty this is the first time ive heard of this o2 spacer idea...i thought it was cheezy and ghetto at first but appearantly some people think its more reliable than an o2 simulator and if it works it works!

 

That's correct. Apparently, the O2 sensors don't measure oxygen percentage, they just measure (estimate) total oxygen content. If you can get less exhuast to the sensor, it will fool the ECU into thinking all is well. Like you said with the "sweet spot", I believe moving them too far out of the flow will also trigger a CEL. I guess it makes the ECU think the O2 sensor is out of range and must be faulty.

I actually used the sparkplug antifouler trick on my C32, and it works perfectly. You just take two of those and screw them together, then insert the O2 sensor into the second one. You will have to drill the second one out (I believe 1/2 drill bit) to allow the tip of the O2 sensor to fit, but be careful not to damage the threads. The first spacer which screws into the exhaust pipe gets left as is; the hole is perfect for correct operation. You will need two antifoulers per side. I don't remember the P/N, but they come in a couple different lengths. You might actually want to combine two different sizes. Try using a short one to get the correct spacing, then screw a long one into the back of that to accomodate the O2 sensor (you'll probably still need to drill out to let the right amount of exhaust in). If I recall, my O2 sensors barely fit into the shorter ones.

 

here is a pic of the one i did and never got a cel.
downpipe3.jpg

 

Thanks for the pic AMX. Is that on your srt6?

 

no ,it is on my PT Cruiser, but will be the same set up ,, the first 02 gets installed like factory the rear (or 2nd one) gets the plug fowler ext.when we cut open a cat we found that the rear 02 senser was not sticking out into the exhaust gas flow as much. that is how we found this fix. . also the auto parts has different sizes to fit what ever spark you have and if you look close the 02 senser thds. are the same a a spark plug,, just take your 02 senser with you and get that size ,,or ask the auto pares to look up you sensor and give you the plug ext for that thd. jim

 

I went to the store and got the size that is every o2 sensor ive ever seen and the thickness from the one in your pics. Low and behold its part number 42002.

Notice the tiny hole in the tip. Did you have to use a drill to waller yours out or was it just fine like this?

 

Im running no cats on the streetl, I've only kept the two front O2's as they are the important ones you need to measure afr. whie the rear O2s moniter the performance of the catalytic converter.

I am using an O2 simulator with a bosch connector plugged into the wiring harness. makes good power without the cats now!

 

Sweet. Which o2 simulator did you use? And where did you find a bosh connector so you wouldnt have to hack your factory harness? Got any pics?

 

you know with halfhymers i forget half the sh@@ I am suppose to remember ,, sorry about that ,,yes i drilled it from the small side till it sensor fit all the way down tight. this way you use your 02 sensors and do not have to buy any 02 simulators jim

 

I took an old O2 sensor and soldered the bosch connector to the o2 sim.

I forget the name of the company that makes it, but i ordered it from a guy who sold them in hotrod magazine aout a year ago.

 

I know some engines are designed to have so much back pressure and then other engines will benefit from having less back pressure than what is put on the car to control emissions and noise.

I have a 2004 N/A running no muffler. Can anyone tell me if effiency/performance wise i would benefit from removing the rear set of cats? If i ever had to pass emissions they would still see the front cats, and i really don't like having to mess with the oxygen sensors so i want to start with deleting the rear cats.

Edit* Sorry when i jumped in this thread i didn't realize it was the SRT-6 section.

 

i have a N/A Catless from the header back you just have to go on needswings and buy the o2 J-Bung. they will make the o2 sensors think there are cats on the car and you will not get a light it works by puting the o2 out of the direct exhaust stream so the o2 doesn't pick up all the fumes and reads clean on the ecu. i had mine for a while and no engine light. AND the talk about car will not know if its running lean or rich the secondary o2s after the cats are only for cat efficiency the two o2s before the cats read air fuel so that wouldn't be an issue

heres what you need
O2JBung.aspxStainless o2 J-Bung