KFLDRAPP2 Table:
 Flash Address: 0x840000
 Description: New 12x12 fixed duty cycle map for controlling the second N75 solenoid (LP turbo).
- Custom Logic Patch:
 Flash Address: 0x83F800
 Description: Injected assembly routine that reads engine speed (NMOT) and relative load (RL), performs a map lookup
on KFLDRAPP2,
 and writes a PWM value to the N249 output pin (P10.3) to control the second N75.
- Hook from Original N249 Output Logic:
 Flash Address: 0x83F80C
 Description: Original MOV instruction that controlled the N249 output has been replaced with a CALL to the custom
routine at 0x83F800.
2. Theory of Operation
This patch is designed to support compound turbocharging on the Bosch ME7.5 ECU by enabling independent control of
a second N75 solenoid.
The original N75 (controlling the high-pressure turbo) continues to function normally using the ECU's built-in PID control
loop.
The second N75 (for the low-pressure/small turbo) is now controlled via a repurposed N249 output (P10.3). The ECU
uses a new map'KFLDRAPP2'
which defines a fixed wastegate duty cycle (WGDC) based on RPM and load. This allows boost from the small turbo to
be progressively
introduced at low RPM, preventing it from overwhelming the high-pressure turbo's ability to spool

The injected logic only activates below 4000 RPM. Above this threshold, the PWM output to the second N75 is disabled,
ensuring
smooth transition to high-pressure turbo operation.
This setup is ideal for staged or compound turbo systems where spool dynamics must be carefully balanced.
3. Tuning Guidelines
To tune the second N75 controller (low-pressure turbo), adjust the values in the KFLDRAPP2 map located at 0x840000.
- Axis Scaling:
 The map uses the same RPM and relative load axes as KFLDRAPP. Ensure the X (RPM) and Y (Load) axis arrays are
consistent.
- WGDC Values:
 The map defines duty cycles in percent (0'100%). A starting ramp from 30% to 80% is recommended.
- General Strategy:
 - Low RPM (2000'3000): Start with 30'40% WGDC
 - Mid RPM (3000'3800): Ramp up to 60'70%
 - High RPM (4000+): No output (handled automatically by logic)
Always monitor boost response and adjust values conservatively to prevent overshoot or surge. Consider implementing
external
safeties such as MAP limiters, EGT protection, or fallback modes

Originally, the logic used a hardcoded value of 4000 RPM as the switchover point, changed this so that the RPM threshold is now adjustable in flash memory. Instead of being fixed, it's stored at address 0x400F0. The default value written there is still 4000 RPM (16bit low high), but now you can tune it easily without editing the code again.