Air Fuel with catless.

[DrumKidd]

I'm thinking about adding an AFR gauge, however, I've read people using the front O2 or the rear O2. How about using the third hole and anther O2 sensor?

Currently, I'm using a custom turbo (S/J/down, whatever you want to use to reference) pipe and the Perrin 3"(turbo-back cat-less). On the replacement cat piping, there are 2 holes for O2 sensors. I'm not sure if the readings would be accurate, but could I use the furthest hole and another O2 sensor to avoid splicing into either of the other O2 sensors. Has anyone tried this method?

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Yellow pointing frontward of vehicle.
Green showing added Sensor hole.

 

[HighSpeed]

It really doesn't matter too much. You will need to simulate the rear o2 with a spark plug defouler in order to no throw a CEL for no cat(search if you don't know what Im talking about on that). People get dyno tuned with a wb o2 stuck in the muffler, so more upstream should be better. I would also recommend highly that you not use a POS light show( narrow band AFR gauge), it really serves no purpose on these cars, or any car for that matter. Save up and get a wb 02 sensor and put it in that last hole you got in the midpipe, that would be perfect.

 

[DrumKidd]

I did the non-fouler trick already. The CEL has been off for about 250 miles now. Pretty cheap effective way to trick the processor.

I just wasn't sure if using that rear most hole would be a sufficient reading.

 

[jbrewer4639]

good to know

 

[HighSpeed]

Yeah the rear whole will give plenty of reading, unless you have a huge exhaust leak.

 

[littlemimus]

make sure not to get a narrowband like i did -.-

 

[HighSpeed]

make sure not to get a narrowband like i did -.-

Yeah, narrow band is just a light show with little if any help for the driver. It can be tempting to buy early on, but please resist becasue the money can be used for something else.