Muuhaha

On longtubes, if you have 2 bungs next to eachother, one in front of the other, does it matter which bung is used for the front o2 and which is used for the wideband? The bungs are literally 2" away from each other. Didn't want one to somehow block the other and give a different reading (even though I don't think that's possible). Thanks!

7LitreC5

Should not matter as long as they are in front of the cats.

Muuhaha

That's what I figured, thanks!

Zip Corvettes

No that is not correct. Yes it matters. If you are using your WB for anytype of calibration then it needs to be the front or first sensor. A sensor has a trailing contamination tail and your normal sensor can pollute the WB sensor and make the readings not as accurate. If you are just mounting a gauge for looks then it will not matter.

Muuhaha

Well in this case, it would be used for tuning. I figured the front o2 is still the one sending the main readings so that one should be in front. I'm not doing wideband simulation or anything. So stock o2 in front of wideband in this case, sound correct?

Higgs Boson

if you are mounting it permanently for observation purposes, it's not a huge deal but if you are only installing to tune then removing, just pull the driver side narrowband and use that bung for the wideband, put the car in open loop and tune it, then put it back in closed loop with the narrowband for regular use.

Muuhaha

Mine will be up permanently for this install. Thanks for that advice!

Zip Corvettes

No, while you are performing any tuning the WB needs to be in front. You are corrupting the data in the WB if it is behind the regular 02 sensor. The WB is always in front. The reason I asked if you were just using is as a gauge in the dash to monitor is because in the case the accuracy of the WB is not really important. For tuning though it is important.

Zip Corvettes

This is how I do it.

Muuhaha

Thanks for the clarification.

So just to reiterate: during tuning, WB is in the front slot (or remove the NB and place a plug in its spot, I'm assuming would work as well). After tuning, the NB should go back in the front slot, and the WB is just monitoring while the NB does corrections?

I think I'm only confused because in previous applications (usually 4 cyl) I would only have a wideband and would simulate the NB through the WB via tuning software. I'm not familiar with how these cars are tuned so I'm not sure how everything needs to be setup.

Higgs Boson

If you are tuning it, you can leave the wideband in, just put it in front and the NB in back (if they are that close). That way you don't have to unhook the NB at all or leave it dangling.

Basically, put whichever one is critical for adjustments in front.

Muuhaha

After tuning is done, all adjustments are made through the NB sensor though, correct? So the NB would have to go back upfront and WB behind it? Or does the WB stay up front forever? That's the part I'm confused about. I'm not sure if the WB is used for corrections like my previous builds or if it's just there to set a more accurate base tune, then just monitoring.

Higgs Boson

Tune the car in open loop (disabled narrowbands) with the wideband in front.

When you are done, put the car back in closed loop so the narrowbands can assist with fuel trims keeping fuel in line for minor changes in temp, altitude, etc. with the narrowbands in front.

The wideband is not used for corrections unless you are actively tuning the car and making changes to the airflow tables. Base tune then monitoring.

Fords (like the Mustang) use widebands full time in place of the narrowbands and even correct real time at full throttle. GM is way behind in this sense.

blown81bu

so if u have a c7 with stock exaust all u need to do is take out front left 02 us that for your wide band and tune in open loop?

Higgs Boson

yes

blown81bu

Im building a 2016 Z51

I think im gonna bypass headers and stay stock manifolds with corsa x
procharger D1
alky meth

i was curious how to hook my wideband up for tuning thanks

Muuhaha

Read the post right above yours... seems like that's the way you would need to go!


Thanks for explaining it to me Higgs!

7LitreC5

I was unaware of that. Thanks for enlightening me. What causes the first sensor to have a trailing contamination tail? If there, say 10 inches, between the first bung and the second bung does that eliminate the contamination issue?

n8dogg

I agree. If you are using a WB for tuning, you definitely want the cleanest and most direct exhaust signal as possible.

If you are using a WB for just a gauge on the dash, then I'd say have it behind your primary.

Muuhaha

Just out of curiosity, how do shops tune cars that DON'T have a wideband in them? Do they install their own for tuning purposes then put back in the narrowband?