Hello --

I've been working on a turbo-back setup for my Evolution IX. It consists of a WORKS downpipe, WORKS HFC and Fujitsubo RM-01A exhaust. The Fujitsubo exhaust doesn't have a O2 sensor bung. Originally I was thinking about having a bung welded onto the HFC, but (in a separate thread), a number of you advised against it.

So... before I take the Fujitsubo to the muffler shop and have them start drilling and welding, I've taken some photos and marked where I think the bung should go. If you guys could let me know if I've picked the right spots for the O2 bung, I'd appreciate it !!!

My first guess is Option A, in hopes that the stock O2 sensor wires are long enough to reach this new location. Based upon my crude under-the-car measurements, I'm guessing 2.5" back from the flange, and slightly to the right of where the screw hole on the flange is.

Option "B" was based on some pictures I found online of exhausts that came with O2 bungs already installed. I'm thinking this one isn't as good of a location.

Top View of Exhaust


Option "A" and Option "B" of where to install the bung


Option "A" and Option "B" - closer view


Close-up of Option "A"


Once again, thanks for your help!!!
RedAustinIX

 

On the mid pipe right behing the HFC. This will reduce wire length. Also drill it in such a way that the O2 sensor does not hit the underbody of the car.

BTW, Perrin makes a 3" hfc with a pre-welded o2 bung. Notice that the bung is post-catalyst - so you can drill the cat portion in such a way to may a O2 sensor work rather than drilling the mid-pipe section...

 

Wait so are you saying you want to put a WBo2 sensor after the cat? I thought you were supposed to place it before the cat?

 

XK120 -- not wideband, just the standard O2 sensor. It's located in the cat on the EvoIXs, and the general recommendation has been to move it to the exhaust when replacing the stock cat with a HFC.

4-BNGR -- when you say "drill the exhaust so the O2 sensor doesn't hit the underbody of the car", do you mean drill it so the O2 sensor is parallel to the bottom of the car? Or at a 90 degree angle?

Thanks,
RedAustinIX

 

more like a 45 deg angle would work better in avoiding clearance issues

 

Yep. Parallel or even slightly degreed downward. That way it'll leave you some room to to the "mechanical cel fix" (spark plug anti-fouler mod).

Nice pipes, btw. I like that the mid pipe retains the 2 resonators...

 

I would sell your Works high cat and buy the Perrin High flow cat or Ultimate Racing test pipe because they both come with a 02 bung on it.

Option A looks like a good spot though