I'm going to install a wideband bung in my stock y pipe to facilitate future wideband tuning. Where should the bung be placed. I know it should be in either the 2 o'clock or 10 o'clock position, but where on the y pipe is the best place? After both cats, right before the joint at the cat-back, or some other place?

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I don't think it really maters to much. I have a STS and I put mine clear back there, so it was after the turbo and it seem to read well and is very responsive. Every thing I have heard said it needed to be after the turbo, but your supercharged, so I don't thing it's all the critical where you put it. You will get a better average of the motor if it is sampling from both pipes, but unless you have a problem with one side of the motor, then that won't mater anyway.

Right before the cat back joint on the y pipe will be fine.

10 or 2 0'clock is right as long as you have 4" or more of clearance from bung for the sensor.;)

Right before the cat back joint on the y pipe will be fine.

10 or 2 0'clock is right as long as you have 4" or more of clearance from bung for the sensor.;)


That's what I needed! Thanks!

What about if you have true duals. Im thinking about getting one from a gp on tech and mounting it at the y just isnt an option for me.

I removed the rear O2 on the drivers side and replaced it with the wideband O2.

If at all possible, put it before the cat as it will have a more acurate reading there than after. When I had true duals, I had the sensor on the driver side just after my header collector. Now with the new single setup, I have it just after my Y-junction and it reads about the same as it did running on one bank.

I dont have cats so can I mount it basically wherever I want or just off the collector?

What kind of sensor are you guys using? And where are you buying them from?

Thanks

mount it before the cat definetely because another form of combustion goes on inside the cat as well, so that would skew your readings. As for someone with true duals, I would put it just after your collector, on either side. A better choice would be to have an x-pipe put in and put it there, but you shouldn't run into any problems "tuning off of one bank". Just watch both your primary O2's to make sure they are readin about the same so you know the 2 banks are about as equally efficient.

I have an x-pipe so I should just drill a hole where the two pipes cross and weld the bung in there?

how far back from the collectors is the x pipe? up to a foot or two should be ok, thats where ya should do it.

I didnt see you had an xpipe in your sig.........now I know to look first.

Once the lts are on the x-pipe will be about a foot and half from the pass side and probably 3 feet from the drivers side since that pipe has to come across under the tranny.

you should be good there!!! Have fun!

thanks bigred.

no problem man, glad to help out!

Just received my Dynojet Wideband Commander from RWTD(they had a good sale price recently). Instructions say before the cats no more than 30 inches from exhaust port. Mount between 9 and 3 o'clock positions at least 10 degrees above horizontal to prevent water accumulation/damage to the sensor.

I dont have cats on my truck so thats not a problem but the less then 30 inches from the exhaust port will mean I will have to moun it on one bank or the other.

Yeah, the 30 inches they say is so you see almost no lag in chnage in A/F from engine to the sensor, but like most shops do, they stick a wideband in the tailpipe. definetely not 30 inches from the port! With a V8 and without having to run 2 sensors to compare, the best place is just as close as possible to the engine in both exhaust paths, as long as its before the cats. the only thing that will change is the lag time between change in A/F of engine and registering on the wideband. but we're talking milliseconds here, so its not that huge of a deal.

If you are using a Bosch LSu sensor it actually works better behind the cats in blown or turbo apps. The sensor does not work above 750 deg C and any back pressure in the exhaust makes it drift off the scale, so this is why doing it behind the cat works well, Less heat and pressure makes it more stable. The cats have no time to really do anything at WOT so readings are just fine. If you have any tuning software just turn of one of the rear o2 sensors and use that bung. I have tried it both ways and the reading are the same exept its more stable and does not go drifting off making it look like its going lean from the heat and pressure. For alot of good information on this sensor check out this link and read the warnings. Link (http://wbo2.com/lsu/default.htm)

When we tuned mine we took out the rear pass O2, turned it off with HP and put the wide band in there. Tuned it to 12.2 at WOT and 14.7 on the highway at cruise. When I had my last dyno session, the AFR layed right on 12.2. Putting the wideband BEHIND the cats allows the AFR to stabilize, better more consistent tuning.

Why install a bung when you have one already ;) Just be sure to use some anti-seize!!

Good tip! Since I didn't get to get it in anyway, this past week. Just as I got things ready to be loosened, an 8" water main broke in front of my house. Flooded out my yard, and driveway, and had water in the basement. Needless to say, I didn't get the bung installed this week!

My dynojet wide band will be here today. :)
Now all I need is the new laptop and HPT.