mrmint69
01-25-2008, 10:28 PM
If i make a 1/4 mile run and hit wot at roughly 30mph what should my O2's be reading? Im trying to figure if the can is running a bit lean since the car starts to loose some power at 85+ mph. I have a datalog so i can check easily.
rskrause
01-26-2008, 08:56 AM
If they are narrow band it should be reading full rich.
Rich
Injuneer
01-26-2008, 04:19 PM
The stock, narrow-band O2 sensors are simply not accurate at anything other than the stoichiometric ratio of 14.7:1, +/-0.1. At the typical A/F ratios encountered at WOT (12.8-13.2:1) they are not very accurate. A small change in operating temperature will cause a larger voltage change than a large change in A/F ratio.
That said, I've seen numbers at WOT ranging from high 700's to over 1000mV. But the best running cars are typically in the range of high 800's to very low 900's. All this is NA.... FI and N2O cars will obviously show higher voltages when tuned correctly.
All of this is fully discussed in my online scan guide:
http://members.aol.com/InjuneerZZ/ScanMast.htm