REV2 Board: Nitrous Injection - bootmod3 CustomROM V2
Overview
Nitrous injection setup with CustomROM V2 is quite elaborate when it comes tuning with nitrous as safely as possible. Nitrous activation happens by setting the value of 1 for it.
Nitrous solenoid output (NOS) is now activated and will be pulsed as per the setup under REV2 → FlexRay Outputs Control → Nitrous Injection tables.
Progressive Nitrous Solenoid Control
Nitrous solenoid can be set up to be pulsed in a progressive manner by using the Nitrous Solenoid Duty Cycle table indexed by Boost (Intake Manifold Pressure) vs Engine RPM.
Nitrous Activation Window
We felt that adding nitrous injection support with the above table would have lacked in many areas to run nitrous in as safe a way as possible.
To provide complete control we’ve added a large chunk of logic to define a nitrous window setup second to none. Tuner can set up nitrous to be active:
Nitrous Activation by Map Slot (e.g. map slot 1 allow nitrous, but not allow in slots 2-4)
Nitrous Activation by Gear (e.g. allow nitrous for launch only in gears 1,2, to get the car off the line, otherwise off)
Nitrous Activation between MIN and MAX Vehicle Speed (e.g. only spray nitrous between 10 and 60mph, otherwise off)
Nitrous Activation by Pedal % (e.g. only allow nitrous to spray when accel pedal % is above 70%, otherwise disallow to prevent spray at part throttle)
Nitrous Activation Based on value between MIN and MAX Nitrous Bottle Pressure (e.g. only activate nitrous if bottle pressure is inside the MIN and MAX value for bottle pressure, otherwise off)
Nitrous Gearshift disable (e.g. switch to enable the ability to turn off nitrous through gear shifts)
Nitrous Reactivation Timer - timer to allow nitrous to re-arm after its been disarmed to prevent uncontrolled on/off situations
Nitrous Compensation Transition Delay Timer for Pre and Post Spray - these define the time given to the nitrous algorithm to establish lambda and ignition timing corrections before nitrous comes on and after nitrous spray ends
Nitrous Configuration and Safeties
Nitrous spray logic requires all of the above activation window settings to be met before it sends nitrous solenoid duty cycle to the REV2. However, once nitrous is active, various safeties are in place to ensure nitrous is sprayed in a controlled manner.
Nitrous Ignition Correction table can be used to set up the maximum amount of ignition timing correction (knock correction) before nitrous deactivates for safety.
Nitrous Ignition Timing Target Override tables can be set up to adjust ignition timing target for nitrous mode. Nitrous Ignition Timing Target Override Mode can be set to a value that determines which of the modes will be used (addition, subtraction, multiplication, or division) using the value in one of the tables for this function. In most cases subtraction mode (value of 2) is used which indicates to this function to take the value in the Nitrous Ignition Timing Target (Subtractor) table and subtract it in realtime from the running Ignition Timing target value. This allows for example to easily pull 4 degrees of ignition timing from the tune when a 100 shot of nitrous is sprayed (e.g. following general rule of thumb being to pull 2 deg of ignition timing for every 50 shot of nitrous sprayed).
The same approach is there for the Nitrous Lambda Target Override to allow richening the lambda target by a set amount when nitrous is spraying.
In addition, we added a safety for Lean Protection. In case Lambda Actual were to go leaner than the timer value set in the Nitrous Lambda Lean Condition Protection Timer table, nitrous solenoid is turned off. In the example below, if lambda actual goes leaner than 0.85 for longer than 250ms, nitrous mode will exit.
REV2 Board: Wiring Instructions for Nitrous Injection Solenoid Output
