Where is the best place for an O2 bung and wide band O2 sensor?

Is there an ideal location in the exhaust to place the wide band O2 sensor?
Is there a less than ideal place?
The easy place it seems would be at the cat-delete, "test pipe".
If the wide band O2 sensor were to be located in the test pipe would it be sensing a tiny bit of air drawn in from slight leaks in the header flange gasket?
The collector area of the headers would be best right?
thanks,
Karl Ellwein

I use PLXdevices.com

Air leaking into the exhaust will affect WBO2 reading. The collector area of the exhaust is a good place for the WBO2.

dave w

Dave W. Picking your brain a bit. Have you ever tuned with the WBO2 in a less than ideal location? Like tailpipe or "test-pipe" .
The reason I'm asking is that I'm trying to find what the pros here are doing for practicality. Every customer gets a bung welded into their header pipe?
When using the less than ideal location, (anywhere south of the header collector flange), what can be done to compensate for the potential erroneous readings?

Quote:

---

Originally Posted by Karl Ellwein

Dave W. Picking your brain a bit. Have you ever tuned with the WBO2 in a less than ideal location? Like tailpipe or "test-pipe" .
The reason I'm asking is that I'm trying to find what the pros here are doing for practicality. Every customer gets a bung welded into their header pipe?
When using the less than ideal location, (anywhere south of the header collector flange), what can be done to compensate for the potential erroneous readings?

---

I think the biggest drawback to the less than ideal location is the "time delay" from commanded injector pulse width to the actual time the commanded injector pulse width is measured by the WBO2. For steady driving condition the time delay is not a concern. For making precise adjustments to AE / PE the delay needs to be understood and compensated. I don't know of any specific way to measure the delay, most likely measured in milliseconds.

dave w

I'm not Dave, but I made an adapter years ago to clamp a WBO2 to a tailpipe for tuning. I use a short section of pipe with a bung on a pair of vice grips and clamp it to the tailpipe. Response time is a bit longer but I find it usable. Not so good when cat is present though.

Quote:

---

Originally Posted by Karl Ellwein

When using the less than ideal location, (anywhere south of the header collector flange), what can be done to compensate for the potential erroneous readings?

---

Look at data log and you'll see a small gap in time. It's not that hard to work around.

Yes usually everyone get's a bung welded into exhaust right after header in the collector. When done insert the plug and your done or ready for next time.
http://www.innovatemotorsports.com/x...cat=250&page=1