Tune mixtures with practical lambda correction math. Convert AFR, trims, duty, and table values accurately. Build safer calibrations using consistent data, checks, and exports.
| Zone | RPM | Load % | Current Lambda | Target Lambda | Fuel Change % |
|---|---|---|---|---|---|
| Idle | 900 | 30 | 1.02 | 1.00 | -1.96 |
| Cruise | 2200 | 42 | 1.05 | 1.00 | -4.76 |
| Mid Load | 3200 | 58 | 0.94 | 0.90 | +4.44 |
| Light Boost | 4200 | 76 | 0.91 | 0.86 | +5.81 |
| Full Load | 5600 | 96 | 0.88 | 0.82 | +7.32 |
Use this sample table to compare measured and target cells before editing your fuel map.
Lambda = Measured AFR / Stoichiometric AFR
Target AFR = Target Lambda × Stoichiometric AFR
Fuel Multiplier = Current Lambda / Target Lambda
Fuel Change % = (Fuel Multiplier − 1) × 100
New Fuel Table Cell = Current Cell × Fuel Multiplier
New Pulse Width = Current Pulse Width × Fuel Multiplier
New Duty Cycle = Current Duty Cycle × Fuel Multiplier
Injector Rescale Ratio = Current Injector Flow / New Injector Flow
Rescaled Cell After Injector Change = New Fuel Table Cell × Injector Rescale Ratio
Lambda tuning helps you control how rich or lean an engine runs. That affects power, heat, fuel use, drivability, and durability. Wideband feedback makes tuning faster because the sensor shows the real mixture under load. A useful tuning process compares the measured lambda to the target lambda for one load and rpm point. This calculator turns that comparison into a direct fuel correction. It also converts lambda to AFR, which helps when logs, tables, or calibration notes use different formats.
Stoichiometric AFR is the air and fuel ratio where the fuel burns completely in theory. Different fuels use different stoich values. Gasoline, ethanol blends, methanol, propane, and diesel do not share the same number. That is why lambda is often safer for calibration work. Lambda stays normalized across fuel types. AFR does not. If you change from gasoline to E85, the same lambda target will show a different AFR target. This calculator handles that conversion for cleaner and more consistent tuning decisions.
A positive fuel change means the engine is leaner than desired and needs more fuel. A negative fuel change means the engine is richer than desired and needs less fuel. The fuel multiplier gives a direct scaling factor for the current table cell, pulse width, or modeled fuel value. This is useful for VE tables, injector pulse width checks, and airflow based tuning. You should still smooth neighboring cells after each change. Abrupt jumps in the map can create unstable transitions and poor response.
Injector changes often require more than a simple wide open throttle check. When injector flow increases, base fuel values usually need to decrease. This calculator estimates a rescaled fuel cell after a new injector size is entered. That gives you a quick planning number before deeper calibration work. It does not replace dead time tuning, latency checks, or pressure compensation. Those details still matter. Yet the rescale output helps reduce startup errors and speeds up the first stable calibration pass.
Log one repeatable pull. Review rpm, load, lambda, duty cycle, and air conditions. Adjust the needed cell with a reasonable change. Repeat under similar conditions. Do not mix cold starts, heat soaked runs, and changing boost levels without noting them. Keep targets realistic for the engine, fuel, compression, and ignition strategy. A cleaner tuning workflow gives more reliable numbers. That is why this calculator includes correction math, injector scaling, exports, and an example table in one simple engineering page.
Lambda is a normalized ratio. AFR is the actual air and fuel ratio. Lambda stays comparable across fuels. AFR changes when the fuel blend changes.
Stoich AFR is needed to convert between lambda and AFR. If the stoich value is wrong, your AFR targets and correction numbers will also be wrong.
Enter lambda when your wideband or tuning strategy uses normalized values. It is usually better for mixed fuels and for comparing results across different fuel types.
A positive correction means the engine is leaner than the target. You need to add fuel by the shown percentage or apply the multiplier to the active table cell.
Yes. Enter the current and new injector flow rates. The calculator estimates a rescaled cell value, which helps with the first pass after hardware changes.
No. Idle and cruise often stay near 1.00 lambda. High load and boosted conditions usually need richer targets for component safety and better combustion control.
Use repeatable logs, not one random pull. Compare similar conditions, smooth nearby cells, and confirm the result before locking in a permanent map change.
Duty cycle shows injector workload. If the corrected duty rises too high, the setup may be near its fuel limit. That is useful during power and injector planning.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.