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Note this guide is an approximation and may contain errors. Caution should be used when using the assumptions made here. The parameters listed here are for BA/BF only, FG uses different parameter names. A separate guide for FG will be added later. Boost Control The BA/BF/FG use two main modes for boost control, open loop and closed loop. FG also uses a third addition which is feed forward control based on RPM. Initially they operate in open loop mode. This is similar to an aftermarket controller eg eBoost etc where you set predefined gains and the system does not rely on any feedback. In open loop mode if your wastegate actuator lost preload over time or failed completely your boost levels could vary wildy. In open loop mode the system uses the following wastegate duty cycle auF0307 - The openloop wastegate duty cycle, used to achieve the desired boost in close loop boost control or the actual wastegate period when in open loop boost control. Closed loop. Closed loop is where the PCM measures the boost pressure and constantly adjusts the wastegate gain using a PID controller The PID controller will use the following table as its setpoint to reach the desired boost auF0306 - The desired boost pressure. A PID Controller works in the following method. Every millisecond it executes the following function (approximation) Error = Desired Boost (auF0306) - Actual Boost (from boost sensor) Wastegate Duty = Open Loop value (auF0307) + Error * Proportional Gain (auF0287) + Error * IntegralSum * Integral Gain (auF0286) This means the Wastegate duty will be added or subtracted to based on the error. A larger error will mean a larger adjustment to the wastegate value. auF0287 - PID Turbo Proportional Gain auF0286 - PID Boost Integral Gain auF11628 - Desired Boost Pressure hysterisis term. The PID controller also uses a hysteresis (deadband) value. This means if the actual measured boost is within +- (auF11628) inHg it will not further modify the wastegate value. This means your measured boost may have an error of within +- 1.46 psi under normal circumstances. auF2776 - HYSTERESIS FOR OPEN LOOP WASTEGATE CONTROL If the boost error (desired - actual measured) is less than 0.15 inHg (0.07 psi) the closed loop PID controller will be disabled and only the open loop duty cycle will be used. This means if your open loop duty cycle table is incorrect you may see oscillations in your boost level as the closed loop PID controller is enabled/disabled over and over again. auF0296 - OVERBOOST REQUIRED FOR OPEN LOOP DUTY CYCLE auF1890 -OPEN LOOP DUTY CYCLE FOR OVERBOOST If the measured boost error is greater than auF0296 inHg (-40 by default) the PID controller will be disabled and the wastegate will be set to auF1890 (0 gain by default) auF2577 - UNDERBOOST REQUIRED FOR OPEN LOOP DUTY CYCLE auF1898 -OPEN LOOP DUTY CYCLE FOR ONDERBOOST If the measured boost error is greater than auF2577 inHg (40 by default) the PID controller will be disabled and the wastegate will be set to auF1898 (gain of 1by default) auF2977 - Boost Pressure error deadband to allow feed forward adaptive control (FG MK1 onwards only) auF2646 Turbo feed forward adaptive wastegate position based on current rpm (FG MK1 onwards only) Feed forward control is enabled if the error is within 1.5 inHg (auF2977) and open loop control is active. This is added to the wastegates final position in the PID calculation to attain better control. If the wastegate has been modified in any way this may cause issues with boost control if it is not modified. DTC Error State When the boost error is > auF1098 (typically set to -5inHG) it will trigger an overboost DTC code P1227. This is a DTC code only, this does not actually set the duty cycle to 0. The duty cycle will be set to 0 via auF0296 . It is possible to leave the DTC enabled but leave the action disabled by only setting auF0296 out of range but not setting auF1098 out of range. Tips if your open loop gains are incorrect the PID controller will have a hard time reaching the setpoint. When tuning you should set the PCM to use open loop only by setting all gains to 0. Dyno the vehicle and ensure your measured boost matches your desired boost table as close as possible, only then enable closed loop afterwards. This will result in your actual measured boost matching your desired boost table with far less deviation from desired. If you modify the turbo/wastegate system you may need to modify the PID gains to account for a faster/slower responding wastegate and also to compensate for additional wastegate flow. Operational modes Error between 0 and +-0.15 inHg closed loop will be disabled and the open loop values will be used. Error between +-0.15 and 3 inHg closed loop will remain enabled however the wastegate position will not be adjusted. Essentially the PID will be frozen and hold last value. Error between +-3 and 40inHg closed loop will remain enabled Error +-40inHg Over/Underboost will be activated. Error between 1.5 inHg and 40inHg Feedforward control will be active (FG only) Overboost Some calibrations allow temporary overboost under specific conditions. Explanation will be added later. Boost by gear Boost by gear is available in the XR6 Sprint calibration from the factory. Otherwise using our custom operating system you can enable boost by gear or speed. This requires the workshop edition of the software.

Hi there, I have tuned 8 of these cars so far, all fg models and 1 ba. Contrary to popular techniques I always tune in closed loop then back fill the wgdc table from the logged wgdc. This takes longer, but I have had good success with it so far. Until now lol. This is my personal car fg mk1 F6 525 pump id1050x pirotta flex fuel, GTX3582, 45mm external gate off housing. 3.5 xforce. I haven't done springs yet which is why I have the boost tapering off at high rpm. The issue I am having is I have a boost error of 1 to 1.5 psi. I am currently commanding 20psi. (boost by gear). This error was worse (2.5psi) I then upped the wgdc from 0.55 to 0.7 which is in the file now. This helped a lot but I noticed in the log that the closed loop is only commanding 0.4 wgdc roughly. I made the hysteresis smaller so it tryed harder to get to 20psi which didn't help. I have upped the gain 30 percent which didn't help so I put it back. I thought about putting 0.72 in the lower wgdc cells to see if it would get to 20psi but I would like to know why the logged dc is way below my initial DC in WGDC table. I made sure I did both petrol and E85 tables as well so it wasn't an interpolation issue. I can put this in Open Loop and do it that way but I thought id see what you guys think. Thanks Mark 05-08-2022 11-50-44 AM Log.teclog FRF560_fan&dc.tec