TUNING
Ignition timing — advance
Definition
The number of crank degrees before top-dead-centre that the spark plug fires. Petrol engines run 5-35° advance depending on load and RPM. Diesel engines have no ignition timing per se — injection timing serves the same role.
Why workshops care
More timing = more power (up to a point) but more knock risk. Stage 1 petrol calibrations typically add 2-5° at WOT vs stock.