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Enrichment Overview

The stack of extra-fuel corrections layered on top of the base calculation, each solving a specific cold or transient problem.

Demo build: this panel is locked

The enrichment column is available in the full game. See Demo vs Full Version.

What it is

The speed-density calculation gives the steady-state fuel for a warm engine. Real engines need more fuel in several specific situations, so Engone layers a modular enrichment stack on top. The layers, roughly in the order they apply over an engine's life from cold start:

  1. Cranking — extra fuel only while the starter turns.
  2. After-Start — a decaying dose of extra fuel for the first minute after it catches.
  3. Warmup — sustained extra fuel until coolant reaches operating temperature.
  4. Acceleration — a transient squirt when the throttle is opened quickly.
  5. Wall-Film Compensation — a different kind of layer: it converts "fuel the cylinder should get" into "fuel to inject". It runs last.

Warmup and after-start enrichment fade out as load rises, because cold-wall losses are a light-load effect.

Why it matters

Each layer exists for a real physical reason:

  • Wall-wetting — fuel condenses on cold intake walls instead of reaching the cylinder, so cold and transient conditions need a richer command to compensate.
  • Cold atomization — cold fuel vaporizes poorly, so more is needed for a combustible mixture.
  • Transients — when load changes suddenly, the steady-state math lags reality for a moment.

These corrections multiply or add onto base fuel; they don't replace it. When the engine is warm and steady, every enrichment layer has tapered to neutral and the base calculation stands alone.

The stock tunes. All three shipped engines load a factory tune that uses wall-film compensation: the cranking multiplier is about 1.03–1.10× (not the classic 3.5×), the acceleration-enrichment addition curve is all zeros, and warmup enrichment starts at 2.0× (I4), 2.2× (V12) or 2.5× (V8) at −40 °C and falls linearly to 1.0× at 60 °C. After-start follows the standard curves.

How to tune it

Tune each layer on its own page, in the condition it targets — cranking while cranking, warmup while warming up. Treat them as independent: a too-rich cold start is a cranking/after-start issue, a too-rich warm idle is a base-table issue, not enrichment.

Rule of thumb

If the engine is rich only when cold or only during throttle stabs, look to enrichment. If it's rich everywhere, all the time, look to the VE and lambda tables.

In the game

FUEL page, right column — FUEL ENRICHMENT. Five cards: CRANK ENRICHMENT, AFTER-START ENRICHMENT, WARMUP ENRICHMENT, ACCEL ENRICHMENT and WALL-FILM COMP. Each has an ACTIVE / INACTIVE chip (crank can also show FLOODED and CLEAR FLOOD) and a live multiplier, and a TOTAL readout sums them. The left readouts box shows the same total as ENRICH.