BRZg2/GR86 RaceROM Boost Control

Owned by Paul Blamire
Last updated: Nov 04, 2024
3 min read

Introduction

The boost control uses CANbus I/O exclusively to drive a wastegate solenoid, there are no OEM output hijacks involved and if you are moving to GR86 or RaceROM v13 and later from the original BRZ RaceROM this is very different! There is no other option and you must use a CAN based interface to add RaceROM boost control.

The boost control requires there to be an appropriate boost target, which can be limited through multipliers for various temperatures and the ignition advance multiplier, and capped based on gear and mapswitch mode.

With the target set, a base wastegate duty is looked up from a base duty map, with a basic proportional correction from a table, and integral map which increments over time based on a table. This can be further corrected for gear and intake temperature before being sent over CANbus to a suitable device that will drive the solenoid base on the duty value it receives.

CANbus output must be enabled, and configured such that the data sent can be received and interpreted by the CAN device.

Additional adjustments are available for ethanol tuning in the FlexFuel function, and further fine tuning can be done using RaceROM custom maps.

There is a fuel cut based boost safety limit, typically for turbo applications to prevent boost levels that may damage the engine

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Boost Control Maplist

 

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Boost Control Logging Parameters

 

 

 

 

 

 

 

 

 

Tuning

The boost control is structured in a way that you first set a target, and then use the control to make the boost pressure reach and follow the target.

The basic use is:

  • If you want increased boost pressure, raise the target in the gear/mode/rpm range you are interested in.

  • If you boost is consistently under target or slow to reach the target, and you want more boost, use more duty, not a higher target.

  • Tune the boost control for steady control using the proportional and integral functions

  • Adjust the boost targets from the maximums for safety, driveability and performance using the multiplier and maximum maps and tune the wastegate control so these targets are achieved.

Use targets to set the desired boost, use wastegate control to achieve those targets

Live data parameters

  • Boost Actual - The current boost level as an absolute pressure

  • Boost Error – Difference between MAP and Boost Target, positive numbers are over boost

  • Boost Delta - The rate of change of the boost pressure

  • Boost Target – Absolute pressure target in bar, measured by the intake manifold pressure sensor

  • Manifold Absolute Pressure – Absolute pressure in bar, measured by the intake manifold pressure sensor

  • Wastegate Base Duty – Output from Wastegate Duty Base maps

  • Wastegate Duty Integral – WG duty added by Integral correction of EcuTek boost control strategy

  • Wastegate Duty Proportional – WG duty added by Proportional correction of EcuTek boost control strategy

  • Wastegate Final Duty - The final value for the duty after all corrections and custom maps.

 

 

 

 

 

 

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