AFR to Lambda Conversion Chart

TK-421

New member
For some who want to learn how the Cobb system works, here is a reference chart to explain the conversion between Lambda and AFR values. Programs like ECUFlash use AFR values to adjust fuel trims, while Cobb uses a Lambda Value. When looking at the two side by side, it's outrageously confusing.

So I've devised this Chart to help you out in figuring out your Lambda Value from a AFR Value.

Lambda to AFR:

Lambda x 14.7

AFR. Lambda
17.64 1.20
17.49 1.19
17.35 1.18
17.20 1.17
17.05 1.16
16.91 1.15
16.76 1.14
16.61 1.13
16.46 1.12
16.32 1.11
16.17 1.10
16.02 1.09
15.88 1.08
15.73 1.07
15.58 1.06
15.44 1.05
15.29 1.04
15.14 1.03
14.99 1.02
14.85 1.01
14.70 1.00
14.55 0.99
14.41 0.98
14.26 0.97
14.11 0.96
13.97 0.95
13.82 0.94
13.67 0.93
13.52 0.92
13.38 0.91
13.23 0.90
13.08 0.89
12.94 0.88
12.79 0.87
12.64 0.86
12.50 0.85
12.35 0.84
12.20 0.83
12.05 0.82
11.91 0.81
11.76 0.80
11.61 0.79
11.47 0.78
11.32 0.77
11.17 0.76
11.03 0.75
10.88 0.74
10.73 0.73
10.58 0.72
10.44 0.71
10.29 0.70
10.14 0.69
10.00 0.68
 
Last edited:

Alin

Diehard Car Enthusiast!
:ty: :bow:
 

IGOTASTi

System Operator
Staff member
You're the bomb!

:ty:
 

HolyCrapItsFast

Drinks beer!
Is this an AccessTuner Pro thing? With AccessTuner Race all you have to do is select "Show Standard Units" under options. :) Regardless this is need to know information for anyone attempting to tune especially if your doing e85 IMO.
 

TK-421

New member
Is this an AccessTuner Pro thing? With AccessTuner Race all you have to do is select "Show Standard Units" under options. :) Regardless this is need to know information for anyone attempting to tune especially if your doing e85 IMO.

Yes it's a Pro Thing, but I think it's important for folks to understand different units of measurement and be well versed. I prefer to tune in Lambda, I just personally find it easier and it's how I was taught. I do whole heartedly agree with the ethanol thing, it goes well to know this also when tuning with race fuels
 
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