Intake Air Temperature Correction, Turbo

Fig. 44 Intake Air Temperature Correction For Ignition:

When the intake manifold pressure is above 1.0 bar (above 0 psi boost), the intake temperature is used to calculate ignition timing correction. The normal timing will be either advanced or retarded, depending on intake air temperature. As the temperature increases with increased boost, the ignition timing will be retarded to prevent detonation, and possible engine damage, Fig. 44.