Hi , i'd like install a dual wideband AFR gauge to read afr values of both banks in but i'm confused about wich an how many o2 sensors i need , i' ve read in some posts that oem prekat o2 sensors are wideband too , so it seems one can pickup the signal from oem prekat sensors wire to the gauge , other people say that the oem sensors are narrowband so you cannot use them for afr gauge and need drilling two more holes in the exhaust to fit the wideband sensor that came with the AFR gauge Kit .
So , before drilling additional holes for additional sensors in my exhaust , i want to be sure if i need it or not .
And if it is needed , where is the best location for additional sensors ?
Thank you very much

 

Why not use datalogging or a Cobb gauge readout instead of an aftermarket gauge?

The values change very quickly, so you likely won't be able to adjust your driving in time, like letting off for a lean condition.

Primary O2 sensors are 100% wideband. Cobb can read each bank individually. Don't drill holes and weld bungs. Problem solved. :-)

 

I run a PLX gauge that pluges into the OBD port but also has modules that can be added for boost/vac and dedicated O2 sensors. The boost module is mechanical and uses a T into an existing Vacuum line. The AFR module uses dedicated wideband 02 sensors (they're actually identical to the stock pre-cat sensors).
You do need to have someone weld in another O2 sensor bung in each side of your exhaust. I have cat delete pipes so it was very easy to just take them to the local exhaust shop and have him install the bungs for 20 bucks.
I have the gauge set up to display the left cylinder bank and right cylinder bank together and it's very useful to see how the AFR's on each bank are close to identical when the engine is healthy. You start to get a feel for when things aren't right by watching the AFR's and even more so if you can compare both banks in real-time.
It also has a peak/hold feature, numeric or graphical display modes, and can show CEL codes when they happen and reset them with a press of a button.

If you go with PLX, do NOT get the touchscreen model. The screen is unreliable. The standard model uses a small 4-button controller that I ran into the center console.