Anti-Lag is designed to reduce turbo lag when stepping off and back onto the throttle.
This is achieved using the following four principles:
·Extra air is bled into the engine via a bypass valve or an adjusted throttle body.
·Ignition timing is retarded to reduce power while letting the expanding gasses flow out of the exhaust valve. This results in a larger volume of air being pushed through the turbocharger's exhaust wheel.
·Extra fuel is added to help cool the exhaust gasses.
·Ignition is cut on alternating cylinders allowing unburnt fuel to enter the exhaust. This unburnt fuel then combusts due to the high exhaust temperatures from the retarded timing. This combustion results in more expanding gasses further increasing the turbocharger's RPM.
This extra exhaust heat and pressure can damage an exhaust system. Do not use Anti-Lag for extended periods of time.
This is the master setting to turn Anti-Lag ON or OFF.
The Anti-lag system will remain OFF until the system is armed. This means neither Cyclic Idle (unless Cyclic Idle is set to 'Always ON') nor Anti-Lag will work until the arming condition(s) are met. Various methods can be used including a Digital Input, Virtual Auxiliary or an Always ON option allowing the system to be armed permanently.
This function allows the ECU to activate a solenoid when the Anti-Lag system is active with Cyclic Idle or Anti-Lag ON. Its purpose is to bleed extra air into the engine and is typically used to adjust/replace the throttle plate stop.
An ignition cut table can be activated to allow unburned fuel to enter the exhaust, this setting turns this table ON and OFF. See Anti-Lag Ignition Cut Table for further information.
This setting enables the Anti-Lag system to take control of the Idle Speed Controller so that extra air can be bled into the engine through it. When ON and in Anti-Lag or Cyclic Idle the Idle Speed Position is controlled by the Anti-Lag or Cyclic Idle Override Tables.
There are two modes of ignition retard available:
·Degrees - Adds the number in the Ignition Retard Table to the current Ignition Timing.
·Degrees Absolute - Sets the current current Ignition Timing to the Ignition Retard Table value.
This engine speed (RPM) needs to be exceeded before Anti-Lag becomes active (AL Enable TP must be exceeded and the system must also be armed). Anti-Lag will stay active as long as the engine speed (RPM) is above this value. For Anti-Lag to become inactive both the engine speed (RPM) needs to fall below this value and the TP(Main) position must fall below the AL Enable TP value and both values remain below their enable values for the duration of the AL Deactivation Timeout. Disarming the system (turning off the arming DI) will immediately cause Anti-Lag to become inactive.
This level of throttle position (TP(Main)) needs to be exceeded before Anti-Lag becomes active (AL Enable RPM must be exceeded and the system must also be armed). Anti-Lag will stay active as long as TP(Main) is above this value. For Anti-Lag to become inactive both the engine speed (RPM) needs to fall below this value and the TP(Main) position must fall below the AL Enable TP value and both values remain below their enable values for the duration of the AL Deactivation Timeout. Disarming the system (turning off the arming DI) will immediately cause Anti-Lag to become inactive.
The TPS Hysteresis setting below adds extra control to this setting allowing hysteresis to be added to the system.
This setting controls the amount of hysteresis on the AL Enable TPS value. The TPS Hysteresis value is added to AL Enable TPS value when entering AntiLag and subtracted when leaving.
e.g.
AL Enable TPS = 70%
TPS Hysteresis = 10%
To enter AntiLag the TPS value must be over the AL Enable RPM and over 70% + 10% = 80% TPS
To exit AntiLag the TPS value must be under the AL Enable RPM and under 70% - 10% = 60% TPS
This function specifies the time after the engine speed (RPM) falls below the AL Enable RPM AND the throttle position (TP(Main)) falls below the AL Enable TP that Anti-Lag remains active for. This is the time that the turbo will remain spooled for once stepping off the throttle. Disarming the system (turning off the arming DI) will immediately cause Anti-Lag to become inactive without waiting for the Deactivation Timeout.
This table overrides the current position of the idle speed (solenoid, stepper motor or ethrottle). This override is used to bleed extra air into the engine when Anti-Lag is active. A standard Idle valve does generally not flow enough air for proper Anti-Lag operation, an after market upgrade is often necessary. This override is only available when Idle Speed Control is setup and will override ISC's Min and Max Clamps. Note: A separate ISC Override Table is provided for cyclic idle.
Note: The ISC Override function will only be visible if ISC Override if set to ON AND Idle Speed Control Mode is not Off.
See Also:
·Anti-Lag Runtimes - A list of the Antilag Runtime Values/Statuses and what they mean