I think this would be the best place to post this question. I am just wondering the best way to go about welding in a o2 bung on a set of hedman headers. thanks

 

Not much to it. Figure out where you want to put it, drill the hole out, weld the bung in.

 

I drilled mine right behind the rear tire, in the main pipes. A 3 wire O2, so it doesn't need to be quite as close.
The "bung" for me was an M18 nut. I stick welded it, did a very poor job, and gobbed on that muffler epoxy stuff. It seemed to work. I think I used a 3/8" drill bit, the end of the O2 sensor isn't that big. Clean the area before you weld it, so you get a nice good weld, and you're pretty much done. Oh, in case you make the same mistake I do, make sure you test fit where you'd put it, I drilled my hole such that the 4" long O2 sensor wouldn't fit, so I had to patch it and redrill. So make sure there's room for the sensor

 

Why?

 

It's a relatively convenient spot for a sensor that's used only temporarily for tuning.

 

Exactly. I just ran a wire from my stereo circuit breaker for power to the heater element, (easy to put on and remove), and the other wires into the passenger seat, they're on the floor now. Then I just hook them onto my digital voltmeter and i'm set.

And I made an ooops, I didn't mean "rear" tire, that would suck, right behind my *right* front tire. My plastic wheel well part is just an inch above it.

 

Do you need to weld it into the headers, or just the exhaust ?

I wouldn't recommend stick welding on exhaust pipe. . . a small mig machine / gun with shielding gas makes the process oh, so much easier, and cleaner.

Here is where I decided to install my Zeitronix WB02, after the y-pipe before the cat.

 

go to the LM-1 website and read ALL the instructions. You will learn that if your car doesn't have cats, it doesn't matter where you install it. Mine is right after my muffler and I run it all the time. It is a great location and super easy to install with a MIG welder. Did it in about 30 min. Drill hole, weld bung, run wires, and thats it. Now I monitor my AF ratio wherever I go.

The mixture is the same all the way through your exhaust. The only reason you need to install into the headers is if you have a 1-wire 02 and it needs the heat from the exhaust to work. A self heated 3-wire works just fine anyplace, as long as you are at least a foot or 2 away from the end tip.

 

For fine tuning, one on each of the header tubes, right outside the head on top. You'll be able to check mixture of each cylinder that way.

 

You could check the mixture of each cylinder that way, but when there's nothing you can do about individual cylinder mixtures, what good does it do?

 

just had mine welded to the top of the collector .have not installed yet hope it clears .

it is the 1 wire so i will reroute the wire to reach .

hopefully it will be in by end of week and will post results.


it fits fine

 

There's alot you can do with manifold design by knowing each individual cylinder's ox readings.

 

What diameter rod did you use (1/16")? Was it an E6013 rod?

 

I think I used a 3/32" E6013. I just touched it up the other day with a 5/64" E6013.
That muffler epoxy chipped and flaked off, that's why I was trying to touch it up. Haven't checked it for leaks since - yet.

 

One of the main reasons that car makers keep the O2 sensor as close to the engine as possible is for fast feedback to the computer. The computer can respond faster to make changes in the mixture if the sensor is closer to the heads. I can't say i've ever placed an O2 sensor way downstream to test the theory, and I don't think i'll take the time.

 

Be sure to weld the bung in empty. No plug or O2 sensor installed. Sometimes the threads pull a bit and whatever is in there will become mired in there for good.

 

Actualy, the one and only reason that O2's are located upstream is that they need heat to work. Newer wide band O2's that maintain their ownheat and don't tolerate being really warm work well even when mounted with a sample tube in the tailpipe