Timing Table¶
The spark-advance map in degrees BTDC across RPM and load — more advance with RPM, less under load and boost.
What it is¶
The timing table is a grid of RPM × MAP / load cells, each holding the spark advance in degrees before top dead center (°BTDC). As the engine runs, the ECU looks up the cell at the current operating point and fires the spark that far ahead of TDC.
The classic shape:
- Advance climbs with RPM. Flame travel takes a roughly constant time, but at high RPM that time is more crankshaft degrees — so the spark must fire earlier.
- Advance retards under load and boost. Denser charge burns faster and is far more prone to knock, so high-MAP cells carry less advance.
In Engone the physics also derives timing behavior from RPM, load, compression ratio, octane, and temperature, so the table interacts with the build rather than acting in isolation.
Why it matters¶
Timing sets how much of combustion's energy becomes torque. The ideal is MBT — the minimum advance for best torque. Fall short and you leave power on the table; overshoot into the knock region and you risk engine damage. The table is where you walk that line.
How to tune it¶
Build the surface to rise smoothly with RPM and pull back in the high-load cells. Advance toward MBT where octane and conditions allow; keep margin in the boost/high-load cells where knock lives.
Rule of thumb
Add advance until torque stops increasing — that's MBT. If torque stops climbing and you hear knock, you've passed the limit: back off.
Watch out
The most dangerous cells are high load / low-to-mid RPM, where cylinder pressure is highest. Be conservative there, especially on low octane or boost.
In the game¶
The timing table is on the Ignition page; the active cell tracks the engine. The knock indicator warns when current advance is pushing the limit.