Ignition Timing Calculator

Calculate optimal ignition timing advance based on RPM, load, and octane rating using empirical SAE correlations.

Input Parameters

Results

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Base Advance
° BTDC
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Load Retard
°
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Total Advance
° BTDC
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Knock Margin
°
Note: MBT (Minimum spark advance for Best Torque) timing is the most efficient advance. Knock-limited timing must stay below detonation threshold. SAE J1349 reference conditions.

Reference

Base Advance = 10 + RPM × 0.006 (max 45°) Load Retard = (MAP / 101.325) × 8° Octane Bonus = (RON − 87) × 0.5° CR Penalty = (CR − 9.0) × 1.2° Total = Base − Load Retard + Octane Bonus − CR Penalty