Cobb Custom Features: GT-R COBB Advanced Boost Control

If you're familiar with tuning the GTR you'll know that the factory system for cutting boost pressure doesn't always work as well as it should.  As such we've created our own custom version that should be able to help provide consistent, accurate cutting to avoid issues with boost creep or over-boosting.  This encompasses several different tables that allow you to set not only a main boost cut level, but to actively drop the wastegate duty cycle depending on atmospheric conditions in order to prevent overboosting from occurring in the first place.






Boost Cut Delay (COBB)


This value specifies a delay, in seconds, that your boost pressure must exceed the value presented in the Boost Cut Primary (COBB) table before a fuel cut will occur.  This essentially allows the car to see that pressure for a certain amount of time before cutting the car, you can drop it to zero if you want an immediate cut, or add a delay if you're okay with the vehicle seeing the occasional boost pressure spike as long as it doesn't last very long.



Boost Cut Primary (COBB)


This table allows for better control of the fuel cut when the vehicle reads that it is over the boost target. The OEM overboost fuel cut isn't always reliable, as such for optimum safety and control over your boost pressure it is recommended to use this custom table instead. Raise the OEM boost cut table values to their max and populate this table with your desired fuel cut thresholds in Manifold Relative Pressure (Sea-Level).

Note: If you set these values higher than what your MAP sensor can read, overboost fuel cut will never occur.



Boost Cut Offset (No Delay)


This value specifies an offset to the value presented in the Boost Cut Primary (COBB) table. If boost exceeds the primary value plus the offset value, a fuel cut will occur without delay. This function is used in conjunction with the delayed boost cut, so either can initiate a fuel cut if the necessary conditions are met.

Note: If you set this value so Boost Cut Primary (COBB) + Boost Cut Offset (No Delay) is higher than what your MAP sensor can read, overboost fuel cut will never occur.




Wastegate Duty Compensation (Baro Pressure)



The settings in this table allow you to compensate for changes in barometric pressure and apply a multiplier to your normal wastegate duty cycle at various RPM ranges.  This table can go from a 0% multiplier up to 400%.  Keep in mind that values over 100% will be amplifying the values found in your normal wastegate tables and will additionally be affected by the multiplier in the Wastegate Duty Compensation (Intake Temp) table.



Wastegate Duty Compensation (Intake Temp)



The table here will provide a percentage multiplier to the wastegate duty cycle based on the temperature seen by the intake air temperature sensor.  This table can go from 0% to 255% values.  Keep in mind that values over 100% will be amplifying the values found in your normal wastegate tables and will additionally be affected by the multiplier in the Wastegate Duty Compensation (Intake Temp) table.