What this table does
Your Target Lambda table sets the mixture you want at each speed and load. The Lambda Air Temp Correction table adjusts that target based on intake air temperature. The most common use is making the engine run a touch richer when intake temperatures get high, for example after heat soak in traffic or late in a track session, to give extra knock margin and help cool the charge.
By default the table uses Inlet Air Temperature across the X axis (left to right) and Manifold Pressure on the Y axis (bottom to top), so you can correct more under boost than at light load. Both axes can be changed to any ECU channel. Press F3 with the table selected to edit or add axis values; if you move an axis value, NSP rescales the cells so the table's shape doesn't change.
How the numbers work
The correction is added to the target, so the sign tells you the direction:
- Negative value = lower lambda = richer.
- Positive value = higher lambda = leaner.
| Target lambda | Correction | Result | Gasoline AFR equivalent |
|---|---|---|---|
| 0.80 | -0.03 | 0.77 (richer) | About 11.8:1 becomes about 11.3:1 |
| 0.85 | +0.02 | 0.87 (leaner) | About 12.5:1 becomes about 12.8:1 |
Those are illustrative numbers, not recommendations. If your software is set to show AFR rather than lambda, the table is shown in AFR terms too, so the same logic applies: a negative entry richens, a positive entry leans. Pick one unit system for your tune and stick with it so every table reads the same way.
How we tune it
- Leave the table at zero in the temperature range your engine normally sees. The main target table handles normal conditions.
- Add small negative values only in the hot columns, and mostly in the high-pressure rows where knock risk is highest.
- Confirm in logs that measured lambda follows the corrected target when the intake gets hot.
- Pair it with ignition air temp correction if you also want to pull timing when it's hot. Fuel alone isn't always enough.
Because the table changes the requested mixture, fueling moves with it, so always check the result against a wideband. Sensor placement matters too: a good air temp sensor after the intercooler gives a far more useful reading than one in the filter box. The rest of the lambda correction family is covered in Lambda Corrections.
