Convert air-fuel ratio to lambda (and back) for any fuel — with rich/lean reading.
Type in either box — the other updates automatically.
Each fuel has its own stoichiometric ratio — gasoline 14.7, E85 ~9.76, diesel ~14.5.
Type a value in either box; the converter fills the other instantly.
Lambda 1.00 = stoichiometric, below 1 = rich, above 1 = lean.
Lambda is the ratio of actual AFR to the stoichiometric AFR of the fuel. Lambda 1.00 equals the chemically ideal mixture regardless of fuel; AFR is fuel-specific (14.7 for gasoline).
Tuners typically target a richer mixture under load — roughly lambda 0.78–0.85 (about 11.5–12.5 AFR on gasoline) — but always confirm on a dyno with knock monitoring.
E85 needs much more fuel — its stoichiometric AFR is about 9.76 vs 14.7 for petrol — which is why it usually needs bigger injectors.
The desktop Softechpro Solutions software corrects checksums for 260+ ECU families and does DPF/EGR/AdBlue/DTC off, Stage tuning and DTC diagnostics offline.
See pricing — €299 one-time