I am going to install the cats within the next few days. Which "bung" does the o2 sensor go in? One sticks out of the pipe and the other one is flush with the pipe.

 

Hahaa. You said 'Bung' and 'Screw' in the same sentence~ Lol! :-)

 

I used the one flush with the pipe, which is exactly what the stock cats use.

 

I know. I was laughing when I typed it. I didn't know how else to describe it.

 

I used the one sticking out of the pipe because it didn't have the cover on it. Lazy ftw!

 

I imagine the long one is the one that was designed for test pipes. It was designed to fool the o2 sensor into thinking there was a working cat installed when there isn't. Like the old spark plug fouler trick.

I think I should use the one that is flush with the pipe since I don't have to worry about a CEL with high flow cats.

 

Let's us know which bung you used....I just purchased a set of Berks and would like to find out. Are there any instructions with the Berks?

 

There are instructions but they are for test pipe installation. The install process is the same but with test pipes you definately want to use the long bung. That I am sure of. The extra bung is for an aftermarket wideband o2 sensor. Since I have an 05, which comes stock with wideband o2 sensors, I will only be using one bung.

I called Berk but the receptionist said the guy who could answer that question is on vacation.

 

I did the same thing and called Berk. Same answer....Everyone that can answer the question won't be back until next week. She recommended sending an e-mail to info@berk. I guess we'll see how responsive Berk is.

You'd think they would provide specific instructions with the HFCs, not just throw in directions for test pipes. Nobody does their job.....

 

I would use the one close to the cat you shouldn't get a check engine light and will be more accurate thats what I would do

 

She told me to email them as well. Since you are going to email them I will wait to hear from you what they say.

 

I've seen Bryan from Berk post in another thread that with HFC's you should just hook it up to the bungs that are flush with the pipe, like stock. I was thinking of putting them in the non-fouler location so that they last a little longer, but will it affect the way the car runs then?

Yeah, my cats arrived at Berk today to be fixed/replaced, and now Bryan is out of town Must be at a show or something.

 

I think it could slightly affect the way it runs because it won't be getting a fully correct reading. That is the reason Berk uses the long bung for test pipes. It limits the amount of exhaust the o2 sensor "sniffs". That could affect the way the car runs. I would imagine it would have a greater impact on cars with the stock wideband o2 sensors.

The more I think about this I am almost positive the bung that is flush with the pipe is the correct one to use.

 

I did the same thing. Awww Crap..

 

^ that is the correct hole ! they are almost like TPs , there is a nonfouler built-in, so that we don't get an CEL ( ha ha teepee LOL )

 

Agree. Its kind of like a built-in non-fouler. The other port may be used for a air:fuel gauge.

 

Yes, but with high flow cats you shouldn't get a CEL. Even without a nonfouler.

 

Well, it appears 50% of the time, the sensor is installed in the front/flush bung and 50% in the rear/protruding bung. Neither front or rear appear to create a problem with a check engine light.

I going to wait to see what Berk has to say and I'll post their response.

 

Well that's a stupid place to put an a/f guage as it will read leaner than actual. An a/f guage should be pre-catalyst next to the headers, not post-catalyst as pictured.

This has been acknowledged by Berk and I believe you can special order them from Berk with a A/F bung before the catalyst.

 

Not true. Depends on the year and possibly the cat's substrate materal and cell count.

My Power Enterprise 400 cell mettalic HFC's threw a cel on my 05 g coupe after 50 miles. Non-fouler fix worked.

New model years are getting tougher to trick due to stricter federal emission requirements.