Roland@pcmtec Posted July 27, 2018 Share Posted July 27, 2018 When tuning with a different wastegate actuator or boost control solenoid it is best to tune the vehicle in open loop first to get your initial open loop duty cycle correct. Once this is correct you would enable closed loop again There are 4 modes the boost control works in in the FG. Idle/Cruising mode (0% duty cycle) Overboost (0% duty cyle) Underboost (100% duty cycle) Closed Loop (Variable %) In closed loop the wastegate duty cycle is determined via the following (this ignores the boost adder functionality at WOT and assumes you have zero'd them out) duty_cycle = auF16463 (predicted open loop duty cycle) * auF0318 (injector duty cycle) * auF16634 (boost multiplier ECT) * auF0315 (Barometric multipler) * auF16475 (desired boost multiplier TPS) + KP + KI Where KP and KI are the PID outputs (closed loop control). So knowing the above we can force permanent open loop control by the following: Setting the PID constants to all zero. We can then set the underboost value to a very high number so that we never get true underboost (100% duty cycle) Set the overboost value to a very low number so we never get true overboost (0% duty cycle) Set the "cruising mode" TP Count to a low number so you never get 0% duty cycle unless you really are at cruise or idle. If you would like a dummys guide change the following items: auF2645 P1228 Timer - Set this to 1000 for the entire table auF2150 P1228 - Wastegate Failed Open (Under Pressure) - Set to "No Error" auF2279 P1227 - Wastegate Failed Closed (Over Pressure) - Set to "No Error" auF16459 Desired Boost (inHG) set this out of range to a high number like 35 auF16475 TPS Boost multipler - Set this all to 1 other than idle/cruise. auF3184 Underboost Required For Open Loop - Set this to a high number like 40-100 auF3204 Intake Cam Adder for boost error - Set the degree adder to 0. This is important otherwise your VCT system will command incorrect angles. auF3264 Exhaust Cam Adder for boost error - set the degree adder to 0. This is important otherwise your VCT system will command incorrect angles. auF3002 Spark Adder/Delta Change in Wastegate - set to 0 auF0286 Integral gain - Set to 0 auF0287 Proportional gain - Set to 0 (try 1 as well, however most likely will be ignored in open loop) auF0296 Overboost to trigger open loop - set to -50 to -100 auF16555 Integral Gain - Set to 0 auF16519 Integral max - Set to 0 auF16453 Integral min - Set to 0 auF0289 Proportional Max - Set to 0 auF0288 Proportional Min - Set to 0 auF1193 P1227 Fault Filter - Recommended to leave unchanged. auF1328 P1227 Fault Filter - Recommended to leave unchanged. auF1898 - Open loop duty cycle for underboost - set to 40-50% auF1098 - P1227 overboost error - Recommended to leave unchanged. auF2625 - Slope due to pre turbing temperature - This function accounts for heat soak into the wastegate actuator. It will modify the final wastegate duty cycle to try and keep a more consistent boost pressure when the exhaust is hot or cold. If you want a completely open loop boost control, set the unitless column to 0. If you leave it as stock, the wastegate duty cycle will change with exhaust temp, however it should give you a flatter boost curve when then exhaust is extremely hot vs cold. auF16680 Boost Clip based on Inferred Turbo Temp - This is not in all FGs, only the later model vehicles. This will clip the desired boost. If you are using proper closed loop boost control, or you are utilising this table, make sure you raise this table to be higher than what you are requesting in your desired boost table. auF0286 - Integral Clip (this is the "cruising mode" table which sets duty cycle to 0% below these TPS values. Set the TPS column to ~150 counts at higher rpm to ensure you always get the commanded duty cycle. Quote Link to comment Share on other sites More sharing options...
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