Lambda value/ AFR correlation

[Mark Romans]

Brad Sheridan wrote:
> 
>  Hi,
>   I can't seem to remember off the top of my head what the relationship
> between lambda and AFR is. Anybody know it? Also, I looked in the archives,
> and saw a few different values for AFR at lambda = 1. One of them was
> 14.57:1, another(the one I'd always heard as being correct) was 14.7:1. The
> NGK sensor data sheet I have shows 14.57:1. Anyone know the correct AFR at
> lambda = 1?
> 
> Thanks,
> Brad

Hi Brad, I have a GM Service Technology Group document that lists AFR vs
02 voltage.


A/F                        02 Volts
   Ratio			   Range
========		   =============

17.1			   0.090    0.110
16.5			   0.190    0.205
16.0			   0.290    0.310
15.5			   0.390    0.410
14.9			   0.490    0.510
14.4			   0.585    0.605
13.9			   0.680    0.700
13.2			   0.780    0.800
12.7			   0.870    0.890
12.1			   0.965    0.985

However I must say that this must be used with a caution. My experience
is that even when I calculate my afr to be 10.14 - 1 @ 4000 rpm, based
on the grams/sec air flow and ms pw of my injectors, my 02 sensor has
never read higher than 813mv, with a 10.4 ms pw. With an 7.9 ms pw the
02 sensor reads 793 mv, so the 02 sensor does not read in a linear
manner the further you go from stoich. Also voltages vary between diff
02 sensors.  Mark.