Closed Loop Manifold Pressure Expected

Closed Loop Manifold Pressure Expected

The “Closed Loop Manifold Pressure Expected” table is an auxiliary table designed to enhance control strategies when using wastegate pressure control, also known as CO2 boost control.



In the video above, we demonstrate how to set up CO2 boost control using wastegate pressure as the controlled parameter. This method is straightforward and easy to tune but may be confusing for the end user or driver at the track, as wastegate pressure numbers do not directly correlate to the desired boost or manifold pressure. This is where the “Closed Loop Manifold Pressure Expected” table becomes useful; it allows wastegate pressure and manifold pressure to be mapped, eliminating the need to remember the exact correlation.

To use this table, the car must first be tuned as shown in the video. Once the boost control system reliably targets different wastegate pressures, the tuner should perform multiple runs at various wastegate pressures to establish a correlation between wastegate pressure and manifold pressure. The example table below illustrates what wastegate versus manifold pressure look like in our car.


With this established correlation, the “Closed Loop Target Pressure” table axis can be adjusted to use “Boost Control Manifold Pressure Expected.”



In this example, when the user sets a target of 20 psi of boost (manifold pressure), the ECU will know it needs to aim for 23.3 psi of wastegate pressure.



The “Closed Loop Manifold Pressure Expected” table can also be further mapped against additional variables, giving users even more control over boost behavior. For instance, this example maps the expected manifold pressure against vehicle speed and a rotary trim knob, but many other variables within ECU settings can also be applied.


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