Tom Wilson
December 27, 2013

Air/Fuel Calculator

Lambda 100% Gasoline E10 E15 E85 Methanol
1.238 18.12 17.42 17.07 12.19 7.92
1.224 17.92 17.23 16.88 12.05 7.83
1.210 17.72 17.03 16.69 11.92 7.75
1.196 17.51 16.84 16.50 11.78 7.66
1.183 17.31 16.65 16.31 11.64 7.57
1.169 17.11 16.45 16.12 11.51 7.48
1.155 16.91 16.26 15.93 11.37 7.39
1.141 16.70 16.06 15.74 11.23 7.30
1.127 16.50 15.87 15.55 11.10 7.21
1.113 16.30 15.67 15.36 10.96 7.13
1.100 16.10 15.48 15.17 10.83 7.04
1.086 15.90 15.28 14.98 10.69 6.95
1.072 15.69 15.09 14.79 10.55 6.86
1.058 15.49 14.89 14.60 10.42 6.77
1.044 15.29 14.70 14.40 10.28 6.68
1.030 15.09 14.50 14.21 10.15 6.59
1.017 14.88 14.31 14.02 10.01 6.51
1.003 14.68 14.11 13.83 9.87 6.42
1.000 14.64 14.08 13.79 9.85 6.40
0.989 14.48 13.92 13.64 9.74 6.33
0.975 14.28 13.73 13.45 9.60 6.24
0.961 14.07 13.53 13.26 9.46 6.15
0.947 13.87 13.34 13.07 9.33 6.06
0.934 13.67 13.14 12.88 9.19 5.98
0.920 13.47 12.95 12.69 9.06 5.89
0.906 13.26 12.75 12.50 8.92 5.80
0.892 13.06 12.56 12.31 8.78 5.71
0.878 12.86 12.36 12.12 8.65 5.62
0.864 12.66 12.17 11.92 8.51 5.53
0.851 12.45 11.97 11.73 8.38 5.44
0.837 12.25 11.78 11.54 8.24 5.36
0.823 12.05 11.58 11.35 8.10 5.27
0.809 11.85 11.39 11.16 7.97 5.18
0.795 11.64 11.20 10.97 7.83 5.09
0.782 11.44 11.00 10.78 7.69 5.00
0.768 11.24 10.81 10.59 7.56 4.91
0.754 11.04 10.61 10.40 7.42 4.82
0.740 10.83 10.42 10.21 7.29 4.74
0.726 10.63 10.22 10.02 7.15 4.65
0.712 10.43 10.03 9.83 7.01 4.56
0.699 10.23 9.83 9.64 6.88 4.47
0.685 10.02 9.64 9.45 6.74 4.38
0.671 9.82 9.44 9.25 6.61 4.29
0.657 9.62 9.25 9.06 6.47 4.21
0.643 9.42 9.05 8.87 6.33 4.12
0.629 9.21 8.86 8.68 6.20 4.03
0.616 9.01 8.67 8.49 6.06 3.94
0.602 8.81 8.47 8.30 5.92 3.85
0.588 8.61 8.28 8.11 5.79 3.76
0.574 8.40 8.08 7.92 5.65 3.67
0.560 8.20 7.89 7.73 5.52 3.59
0.546 8.00 7.69 7.54 5.38 3.50

This chart compares methanol (the other alcohol fuel), ethanol, gasoline, and the three popular ethanol/gasoline blends. It’s a handy tuning reference when deciphering Lambda-meter readings, or when simply educating yourself on how these different fuels want to mix with air. Thanks to Ken Christley for generating the chart.

Horse Sense: Alcohol comes in two varieties: methanol, which comes from wood; and ethanol, which comes from grains. Your car can drink both kinds—you cannot. Ethanol is the stuff in beer; methanol is a deadly poison.