Catles DP Defouler Question

[bczracecar]

I've searched but haven't found quite the answer I'm looking for. If someone who has experience tuning these cars could chime in, that'd be great.

I recently purchased a catles DP and have a question about the rear O2 sensor. I am going to be running a tune that deletes the CEL for the O2 sensor, however I am wondering if I should run the defouler or not in case if I ever need to revert to stock tune for warranty work. I've heard some people say that the rear O2 only monitors for cat efficiency and I've heard other people say the rear O2 actually can adjust AFR.

I'm basically asking if there is any reason for me not to run the defouler with my catless DP. To be safe I'd like to run it in case I ever have to flash back to stock so it doesn't throw a CEL, but if running the defouler means that I'll be messing up my AFR, then it's probably better for me to leave it out.

Anyone feel free to chime in here! In for answers...

 

[Ghostwhite]

Mountune told me not to run the defouler "especially with a tune". Idk anymore than that

 

[bczracecar]

Mountune told me not to run the defouler "especially with a tune". Idk anymore than that

That is literally almost the opposite of what I've heard from everyone else. Haha...

 

[Ghostwhite]

I was in the process of doing datalogs for my tune when he told me. Here's what he said. Not really any more detail

 

[bczracecar]

I was in the process of doing datalogs for my tune when he told me. Here's what he said. Not really any more detail View attachment 2646

What brand is your DP if you don't mind my asking?

 

[Ghostwhite]

CPe

 

[bczracecar]

CPe

Hmm I wonder if their "simulator" is different than the spacer I got from 2J racing with my DP. The "defouler" I got literally just moves my O2 back a little bit. So I'm not sure how much that can alter readings. Where are Randy/Freektune/Panda with their thoughts? Haha.

 

[FocusMike]

Hmm I wonder if their "simulator" is different than the spacer I got from 2J racing with my DP. The "defouler" I got literally just moves my O2 back a little bit. So I'm not sure how much that can alter readings. Where are Randy/Freektune/Panda with their thoughts? Haha.

That's what a defouler is supposed to do. Basically the spacing exposes less of the sensor tip into the exhaust so that it doesn't alter your A/F ratio and throw a check engine light whenever you go catless. As long as you don't use the defouler with the tune its not going to have any negative affects.

 

[bczracecar]

I'm wondering what exactly the rear O2 monitors. If it only checks to see if the cat is working, or does it act as a wideband and have the ability to alter AFR?

 

[D1JL]

The rear O2 sensor in this car is only used as a Cat Efficiency Sensor it is NOT a wide band sensor.
Using a anti-fouler spacer only backs the sensor out of the exhaust stream so that the sensor reacts slower and therefore it does not report the same waveform to the ECU.
Using an anti-fouler will NOT hurt anything.
What Randy was saying is about a simulator, this should not be used.
To my knowledge there is no simulator that works with this car anyway (I have tried).

I have known/used this trick for many years, with and without tunes.
It is also something I used to look for.
I was a California Smog Inspector/Tech. for over 12 years.
Now retired ASE Master Auto Tech.



Dave

 

[bczracecar]

The rear O2 sensor in this car is only used as a Cat Efficiency Sensor it is NOT a wide band sensor.
Using a anti-fouler spacer only backs the sensor out of the exhaust stream so that the sensor reacts slower and therefore it does not report the same waveform to the ECU.
Using an anti-fouler will NOT hurt anything.
What Randy was saying is about a simulator, this should not be used.
To my knowledge there is no simulator that works with this car anyway (I have tried).

I have known/used this trick for many years, with and without tunes.
It is also something I used to look for.
I was a California Smog Inspector/Tech. for over 12 years.
Now retired ASE Master Auto Tech.



Dave

This ^

Thank you very much. This is the kind of response that I have been looking for. I figured as much but wasn't sure. Another indication that the rear O2 is only a cat efficiency sensor is its cost. The front O2 is $75 while the rear is $36.

I'll be running the defouler with my DP!

 

[COBB Tuning1]

Input from the rear O2 sensor can dictate fuel trim changes up to 20%. Therefore, if the sensor is not in its stock location, you could have issues. We never recommend using a rear O2 sensor spacer, simulator, etc.

Ian

 

[Ghostwhite]

My O2 simulator made my car run without a check engine with a Catless downpipe on stage 1. It works

 

[bczracecar]

Interesting responses. I'd love a few more opinions.

 

[D1JL]

I would never presume to know more than Ian but it is info I have never heard before.
I called a buddy that works for Ford Engeneering and he has not heard of this either.

I would then follow Ian's lead as he probably has more experience working inside the ECU and leave it out.
If you do need to go in for service, it only takes a few minutes to put it back in.



Dave

 

[lessard.dcj]

Im running 2j race dp and the defouler. The car still throws codes. Any advice on this?

 

[bczracecar]

Im running 2j race dp and the defouler. The car still throws codes. Any advice on this?

Well that's good to know. If you're still throwing codes even with the defouler, I may as well not even bother running it.

A proper tune will fix your CEL problems.

 

[rodmoe]

If you can get away with running a Stg 3 OTS tune they have the P code for cat eff. Turned off or if you have the ATR software you can do this for yourself or ask your tune supplier to do this .

 

[bczracecar]

Installing in two hours. To defoul or not, that is the question. Haha

 

[lessard.dcj]

I dont have the intake or intercooler to run stage 3. Full 3 inch turbo back ex though. Could i run stage 3 anyway? It is Canada and winter time so temp will not be an issue no matter how i run it.