Lambda Target Table¶
The map of desired lambda across RPM and load. Fuelling and closed-loop trim aim at these numbers.
What it is¶
The lambda target table is a 16 × 16 grid of RPM × MAP / load cells, each holding the lambda you want the engine to run at that operating point. The editable range is λ 0.50 – 2.00 (step 0.01, large step 0.05). It is the goal, not a measurement — the speed-density fuel calculation aims for it, and closed-loop trim fine-tunes toward it.
Why it matters¶
This single table sets the character of the tune: economy, power, and safety all come from where you place these numbers. The stock tune looks like this (load = MAP ÷ barometric):
| Region | Stock target λ |
|---|---|
| Up to 70 % load | 1.00 (stoich) |
| 70 → 90 % load | blends toward power enrichment |
| 90 %+ (wide-open throttle) | 0.85 at low RPM → 0.81 at the limiter RPM |
Cold operation pulls the effective mixture richer still, layered on top by the enrichment stack.
You can run lean (> 1.0) in light cruise for economy, but only where the engine tolerates it. The engine's best-power mixture is about 0.98 at idle load, falling to about 0.88 at WOT: going leaner than best-power loses power; going richer costs a little power but cools the charge.
How to tune it¶
Set lean targets only where the engine is lightly loaded and cool enough to tolerate it; bring targets to stoich through the mid-range; and richen toward the WOT values as load and RPM climb so the charge stays cool and knock margin stays healthy. See Editing Tables.
Rule of thumb
Build the table in bands: a lean cruise plateau, a stoich shelf, and a rich WOT ridge. Smooth transitions between them prevent surging as load changes.
Watch out
Lean targets at high load are dangerous. If in doubt, target richer — fuel is cheaper than pistons.
On a boosted engine
Engone currently simulates naturally aspirated engines only. For background: a boosted engine packs far more air into the cylinder, so the tune changes — target lambda moves richer (to cool the charge and protect against knock), ignition advance comes down in the boosted cells, compression ratio is usually lowered, and higher octane matters more. See Boosted Engines (Background).
In the game¶
LAMBDA page, left. The bottom bar shows RPM, MAP, TARGET and ACTUAL, and a live tracer dot
marks the operating point. The right column holds the closed-loop controls — see
Closed-Loop Fuel Trim.