Problem with bung W02 bung placement

[rrrocketman]

I've run into a potential issue with my upcoming AEM install. See I have the sensor and rather than get a bung welded I opted for the DIY solution which is the no-weld 2.5" bung, a metal cuff and gasket with the bung already welded. The problem is I just realized this has to be installed on straight pipe. Looking at pictures of the underbody of the car, I can't see a straight section of pipe to install this cuff onto that's ahead of the cats. Downstream there is a ton of it but that's no good for taking an O2 reading. Am I correct that this no-weld bung cannot be installed ahead of the cat or is there a section of pipe I can't see where it can be installed? Or is there a clever work-around? I don't want to get into drilling holes only to find out I can't install the thing. Thanks.

[rrrocketman]

I'm supposed to do this job tomorrow so I'm kinda desperate for an answer if anyone can help a brother out.

[rrrocketman]

Anybody? 1 hr away from this job :(

[Test_Eng]

Originally Posted by rrrocketman

Anybody? 1 hr away from this job :(

I gutted both of my cats (PITA) and installed my AEM gauge in the rear O2 driver side port. Didn't want to remove and weld to the headers. Make sure your tuner disables the rear O2 sensors if you go this route.


Not sure what headers you have but there is not a lot of room on Kooks headers.

[rrrocketman]

I have stock everything. I just want to know if there's straight pipe before the cat to install the cuff or not because if I get under there and make a mess I can't go back.

[dcpatters]

Originally Posted by rrrocketman

I have stock everything. I just want to know if there's straight pipe before the cat to install the cuff or not because if I get under there and make a mess I can't go back.

So the exhaust, manifolds, cats are all factory?

[rrrocketman]

Yes

[rrrocketman]

I should also mention that this cuff only works on pipes between 2.25 and 2.5", maybe 2.75" also, so I dunno what diameter header pipes are but this product was meant for the exhaust line.

[dcpatters]

There's a way to utilize the factory O2 bung for a wideband. You need a factory connector though. Basically wideband in factory O2 position, and connector to the factory O2 sensor, with sensor just mounted somewhere.

Otherwise, you could remove the one factory cat pipe and mount the wideband opposite the front O2, can't recall of space tolerances. Does the wideband adapter you have position the sensor deep into the airstream or flush?

[rrrocketman]

Probably right in the middle of the pipe. It's an AEM design specifically for their own kit. I can't cut any pipe. Buying the "no-weld" bung was specifically done to avoid cutting or welding as much as humanly possible.

I've ready about using the factory bungs but I don't see how that would work. Using the first o2 bung would make your closed loop fuel trims stop working. Using the second bung would be after a cat so your AFRs would be inaccurate.

[dcpatters]

Originally Posted by rrrocketman

Using the first o2 bung would make your closed loop fuel trims stop working.

Negative, I've done it, tuned my car when I had the factory cat's + exhaust in place. It works. O2's oscillated, STFT & LTFT's all worked on both banks.

Anyway, I understand what you are trying to achieve, with the no welding solution, makes sense. Let us know how it turns out.

[1KillerSS]

Why dont you just use one of your factory post o2 sensors? If your getting a tune you wont use them anyway.

[rrrocketman]

I'm very interested in what you guys are saying about the factory o2 sensors since I can't understand the logic. You've got 2 o2 sensors right? 1 before the cats and 1 in between them. The forward sensor is responsible for providing feedback to calculate the AFR and adjust the STFT and LTFT values while the second aft o2 sensor merely checks catalyst efficiency for emissions purposes. If I'm wrong about any of that please correct me. So my understanding is, if you take out the forward o2 and put the wideband in there, your fuel trims would either not have any signal to work from OR they might work off the second o2 sensor? Either way you either get no closed loop or your closed loop will be offset by some error due to the effects of the first cat. Please advise.

Also I use HPT to tune my own car so I can do whatever I need to do but I would like to keep my closed loop. Where I live, tampering with emissions components is a big no-no.

[1KillerSS]

You have 4 one before the cats and one after, on each bank. If your tuning your car, then all you need to do is turn off the codes for the rear sensors. Disconnect one of the post cat sensors, and disable the associated codes with it. Zip tie the loose harness out of the way.