What O2 Voltage for 12.1:1?

[glh1985]

I search but couldn't find the conversions. What O2 Voltage should I be looking for on my scanner to have an A/F of 11.5:1 - 12.1:1...I know probably around .98v but I would like to know exactly what the voltage should be at these two A/f Ratio's.

[RPMurph]

its hard to measure exactly as narrowband isnt that accurate. This is a good idea of what you should aim for tho.

From 3barracing.com for their Dawes Device

First light: Red = .78 to .90v = too lean

Second light: Yellow= .90 to .94v = Good, but your on the edge

Third light: Green= .94 to .98v = Good, with some room for safety

Fourth light: Blue= .98v and up = too rich

[GLHNSLHT2]

and my narrowband Bosch O2 sensor never showed more than .88v even when it pegged the wideband at over 9.0:1. The narrowband sensor is only good to tell the ECU when the car is around 14.7:1. If you want to know the true a/f ratio you're gonna have to get a wideband.

[glh1985]

I want to run rich since I my goal is to make 25psi, I have a dawe's and an OTC 4000 which gives a pretty solid votage reading...thats why I wanted to know in volts so I could be sure I am running at least 12.1:1 but I think what I'll do is play with the fuel in small increments until I just get the blue light right on the edge. I am guessing the green is at 12.5:1 that is why I think I want to run closer to blue.

[GLHNSLHT2]

I don't think you get it. Over a certain a/f the narrowband outputs basically the same voltage. I monitored my NB o2 with an OTC 2k and a NB gauge and can custom tune the ECU. The gauge was reading 9 lights. The OTC said .84. So I added 30% more fuel to the WOT curve. Doing this the OTC only got to .88v and the lights on the gauge didn't increase. I got a wideband setup a couple weeks later and found I was at a true a/f ratio richer than 9.0:1 with that tune. So you can't trust what voltages the the narrowband O2 is putting out no matter if your scanner is giving you an exact voltage or not because that voltage does not accurately represent the a/f ratio.

[GLHNSLHT2]

What is a wideband?


read this. good info

[xrattiracer]

yep, there is absolutely no correllation between voltage and a/f ratio on narrowband sensors. all you know is that it is richer or leaner than stio.
anyone that claims otherwise is completely dearranged. things like exhaust temperature, fuel additives, weather conditions, etc, have a huge effect on the sensor's output voltage as well.