Calibration Refinement (Using a Load-Based Chassis Dynamometer)
Perform initial testing at lower boost
After choosing the most appropriate starting point calibration, prepare to test and refine the calibration on a load-based chassis dynamometer. When creating a custom tune, it is best to begin testing under low load (boost) conditions by lowering values in the "PUT Setpoint" table as well as the corresponding "Mass Air Set Point for Torque Intervention" and/or "Maximum Torque Manual/Automatic" tables. This lowers the requested load (boost). Testing done at lower boost will allow you to assess the calibration without putting the motor under potentially dangerous conditions. Start the tuning process by loading this "low boost" starting point calibration onto the vehicle.
Increasing airflow/torque target to attain greater boost
The Volkswagen 2.0t is a "Torque/Airflow Target" based system, meaning it uses a complex routine to reference multiple tables based on conditions (Barometric pressure, Atmospheric Temp, Current Knock Condition, Coolant Temp, Charge Air Temp. EGR, Turbine flow Etc.) to achieve its target load/airflow.
There are many limits and targets surrounding load/airflow and these are what are typically manipulated in order increase HP and TRQ. The main control for the boost system is the "Maximum Torque Manual/Automatic" tables. These tables are the X axis reference for the requested airflow which is derived from "Mass Air Setpoint for Torque Intervention" tables. Raising the requested torque in "Maximum Torque Manual/Automatic" will increase the requested mass air flow per stroke (Z table data) thus raising the calculated boost target from the "PUT Setpoint" table. The maximum boost pressure and request is calculated from the "PUT Setpoint" table. This table is referenced from by calculation derived from the "Mass Air Setpoint for Torque Intervention". The data from "Mass Air Setpoint for Torque Intervention" is used as the X axis lookup. It is important to keep the X axis and the Z data consistent on the "PUT Setpoint" in order to keep the system operating properly. (See OTS data for examples)
Boost control logic in the Golf R remains much the same with the exception of the PUT setpoint acting as a ceiling, all boost calculations are derived from the base "Mass Air Setpoint for Torque Intervention". Manipulating the data in these tables along with the "Maximum Torque Manual/Automatic" will allow for greater boost set point calculations. Logging "Boost Pressure" and "trgt. Boost Pressure" will allow you to see where the system is targeting boost. Logging "Engine Speed"(Y Axis) and "Driver Requested Torque"(X Axis) will show where adjustments can be made to manipulate the final boost request.
See: BOOST/WGDC system for more detail and logic flow chart.
In order to gain understating of the ECU's current operation we should monitor "Air Mass Intake Manifold per Stroke" (to determine actual engine load) as well as all relevant torque and turbo speed monitors to assure we are within the requested limits.
An important thing to understand is the ECU will run the lowest load/trq/limit being requested or limited to.
Even without any mechanical changes to the stock boost control system it is possible to achieve boost levels at the edge of the stock turbocharger capacity. At sea level, aggressive tuning using the stock boost control system can achieve 29+ psi mid-range and more than 24 psi at redline.