Since the K24/26 hybrid turbos are larger machines, running on K-04 boost maps, should result in about the same boost pressure as the K-04s with slower spool up response time, not excessive boost. The boost controller is a 3 mode PID controller, (Proportional/Integral/Derivative) with actual boost pressure feedback for comparison to the requested boost, for offset/rate/reset response to drive the N75 control pressure output value accordingly. the N75 control voltage PWM duty cycle is adjusted by the PID controller output to achieve the necessary boost pressure and associated torque development. Therefore I don't believe there is any risk of excessive boost pressure or out of control boost regulation. With torque demand base engine management two main factors are used as inputs for boost pressure control, the MAF meter output is used for engine load determination, and the MAP sensor output is used for boost pressure measurement. Boost pressure is one of the main torque control variables used by the ECU to match torque achievement with the sum of the torque demands at any instant. If the ECU uses drive by wire throttle, the engine management is based on torque demand. Mechanical throttle control uses a different boost control model in the ECU software, but is also a PID controller configured in software. In the specific boost pressure control for mechanical throttle control, the larger turbos running with K-04 tune, would most likely not boost as much as the K-04s due to the larger turbine and reduced spool up response. Given enough time, the larger turbos should develop about the same boost as the K-04s. I don't know of any way the larger K-24 based turbos could accelerate out of control, developing excess boost pressure when controlled by the K-04 tune, with everything operating normally.
Like Daz said, the outcome will either be limp, unstable boost, or extreme overboost depending on the tune.
The torque model outputs desired torque, this is converted to desired load, and then target boost pressure. Boost pressure is tightly regulated while the previous two are not.
If DLDR was tuned tightly for the K04, then the car may go into limp due to underboost (slower spool). Otherwise depending on target boost pressure it will oscillate or overboost.
While building boost pressure, P will shoot high and easily exceed TVLDMX keeping N75 dc above 95%. During this time, I is winding up and will definitely reach ldtvmx, which for a K04 is going to be much higher than needed for the K24. Once, target boost pressure is approached, D will not be great enough to pull DC down enough to avoid overshoot because I is way too high. If boost control is closed loop at this time and target boost pressure is low enough, boost will oscillate wildy from the overshoot and different wastegate response. If the ECU is closed loop, the car will boost beyond 30 psi due to dc being locked above 85%.
