Subaru 99 Anti-Lag setup

Subaru Impreza plug n play ECU FAQ's

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RickS
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Subaru 99 Anti-Lag setup

Post by RickS » Tue Jan 22, 2013 10:33 am

SUBARU 99 ANTI–LAG CONTROL (PBW)

The idea here is to maintain a relatively high airflow through the engine to keep the exhaust mounted turbine compressor running at speed to avoid turbo lag and hence improve throttle response. The PBW system can be enabled either by a drivers switch or by the throttle position at ‘power on’.

If option TPS_ALS is OFF, then PBW active if all following met:
i) ECU PBW Pin is at 0v (Drivers Switch, usually pin B03)
ii) Air temperature is < PBW_Temp/ALS_Air
iii) Engine_Speed > ALS_ON_Speed

If option TPS_ALS is OFF, then PBW inactive if any:
i) ECU PBW Pin is at not 0v (Drivers Switch)
ii) Air temperature is > PBW_Temp/ALS_Air
iii) Engine_Speed > ALS_OFF_Speed

If PBW is enabled, the ignition timing is modified by the TPS Retard factor and a proportion of sparks are disabled by the Spark Limit map and fuel injection events are skipped in the Fuel Limit map. Enabling ALS is done by a driver’s button in the examples above.

If option TPS_ALS is ON then PBW active if all following met:
i) Parameter TPS_raw > 128 at power on
ii) Air temperature is < PBW_Temp/ALS_Air
iii) Engine_Speed > ALS_ON_Speed

If option TPS_ALS is ON then PBW inactive if any:
i) Parameter TPS_raw < 128 at power on
ii) Air temperature is > PBW_Temp/ALS_Air
iii) Engine_Speed > PBW_OFF Speed

This controlled by the TPS Retard, Spark and Fuel Limiter 3D lookup tables with Inputs Engine Speed and Throttle. Enabling ALS in the above two examples is by throttle position at power on (i.e. Throttle Position Sensor raw value above 128 at power on). Options ALS_Arm and ALS_release govern the activation time.

Engine Speed Axis 19 sites 800 to 8000 rpm in 400 steps. Throttle Axis 14 sites, 0 to 130. The range for the Output Limiter is 0% for no cut to 99.6% which will be almost total cut.

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