Is an ignition advance angle of 12 degrees or 9 degrees better?
3 Answers
An ignition advance angle of 9 degrees is better, for the following reasons: The ignition advance angle is generally between 6 and 12 degrees. A 12-degree ignition advance angle is too large compared to 9 degrees, which can lead to delayed ignition. If ignition is delayed, the gas will have difficulty performing work, fuel consumption will increase, efficiency will decrease, and exhaust noise will also increase, affecting the engine's working efficiency. Additional information: Ignition advance refers to the spark plug firing before the engine piston reaches the top dead center of compression. The angle through which the crankshaft rotates from the moment the spark plug fires until the piston reaches the top dead center of compression is called the ignition advance angle.
There's no absolute answer whether 12 degrees or 9 degrees of ignition advance angle is better—it really depends on your specific vehicle condition. From my experience repairing many engines, this matter is quite complex. If the car operates at high altitudes or frequently uses low-octane gasoline, 9 degrees is more stable and less prone to knocking. But for those pursuing power, 12 degrees delivers more punch with quicker throttle response, especially suitable for highway driving or hill climbing. However, excessive advance angle increases engine temperature and accelerates piston wear. Modern cars come with knock sensors for automatic ECU adjustment, while for older manual-tune vehicles, it's best to measure cylinder pressure first before deciding.
I think whether to choose 12 degrees or 9 degrees for the ignition timing depends on your driving habits. For daily city driving, 9 degrees is more suitable, offering stable fuel consumption and engine protection. But for long-distance driving or racing enthusiasts, the 12-degree setting delivers a real kick-in-the-back feeling. A rally-racing friend of mine mentioned that setting it to 12 degrees gives a powerful acceleration in corners, but it requires 95-octane fuel to support it. Actually, for regular family cars, it's safest not to tamper with the factory settings—keeping it between 8 to 10 degrees is ideal. Getting the ignition angle wrong might even cause your car to fail the emissions test during the annual inspection.
