Conversion Table - Lambda to Air / Fuel Ratio
Air / Fuel Ratio
Lambda
Gasoline
Alcohol
Gas
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1.55
1.60
10.3
11.0
11.8
12.5
13.2
14.0
14.7
15.4
16.2
16.9
17.6
18.4
19.1
19.8
20.6
21.3
22.1
22.8
23.5
4.5
4.8
5.1
5.4
5.8
6.1
6.4
6.7
7.0
7.4
7.7
8.0
8.3
8.6
9.0
9.3
9.6
9.9
10.2
10.9
11.6
12.4
13.2
14.0
14.7
15.5
16.3
17.1
17.8
18.6
19.4
20.2
20.9
21.7
22.5
23.3
24.0
24.8
Diesel
10.2
10.9
11.6
12.3
13.1
13.8
14.5
15.2
16.0
16.7
17.4
18.1
18.9
19.6
20.3
21.0
21.8
22.5
23.2
Air–fuel ratio (AFR) is the mass ratio of air to fuel present in an internal combustion
engine. If exactly enough air is provided to completely burn all of the fuel, the ratio is
known as the stoichiometric mixture, often abbreviated to stoich. AFR is an important
measure for anti-pollution and performance-tuning reasons. The lower the excess air,
the "richer" the flame.
In naturally aspirated engines powered by octane, maximum power is frequently
reached at AFRs ranging from 12.5 to 13.3:1 or λ of 0.850 to 0.901.
For pure octane the stoichiometric mixture is approximately 14.7:1, or λ of 1.00
exactly.