VE Table¶
Volumetric Efficiency — how much air actually fills the cylinder compared to its theoretical maximum, mapped across RPM and load.
What it is¶
A cylinder of a given size should swallow a fixed volume of air on every intake stroke. In practice it never fills perfectly: airflow has inertia, valves open for a limited time, and the intake and exhaust create pressure waves. Volumetric Efficiency (VE) is the ratio of the air that actually got in to that theoretical maximum, expressed as a percentage. The VE table maps VE across RPM (horizontal) and MAP / load (vertical).
Why it matters¶
VE is the heart of the speed-density air-mass estimate. If the ECU's idea of VE is wrong, its idea of air mass is wrong, and the fuelling is wrong by the same amount. A VE error at idle is especially nasty: it makes the mixture wander, which makes RPM hunt up and down.
In Engone the underlying physics computes its own VE from the build — port flow, valve and camshaft timing, intake Helmholtz resonance, exhaust scavenging, and temperature. The table is how you teach the ECU the shape the engine actually has.
How to tune it¶
Read the table as a map of where the engine breathes well: peaks where intake and exhaust tuning line up, dips where they fight. Tune at a steady operating point, compare measured lambda to the target, and correct the cell you're sitting in.
Rule of thumb
If measured lambda is leaner than target at a cell, VE there is set too low (the ECU underestimated air and under-fuelled) — raise it. If it's richer, lower it.
Watch out
Don't chase a hunting idle by hand-editing single idle cells wildly — small, smooth corrections keep the surface stable. A lumpy VE table makes transitions unpredictable.
In the game¶
The VE table lives on the Fuel page as a grid of RPM × MAP cells. The cell nearest the current operating point is highlighted as the engine runs.