1.1.2 firmware enabled DC CL launch control that allows user defined pre-load on the drivetrain
Note 1: NEVER ATTEMPT TO PERFORM LAUNCH CONTROL UNTIL GCU CLOSED LOOP DRIVE AND SHIFTING IS ADAPTED FULLY Note 2: IMPROPER SETTINGS MAY DAMAGE YOUR POWERTRAIN. MAKE SURE TO HAVE IT SET UP CORRECTLY
Launch control prerequisites:
- Brake switch input (mandatory global input)
- Launch control enable switch (can be set to constant value for permanent ENABLE (1024) or DISABLE (0)
- Pedal position sensor (mandatory global input)
Conditions to enable DC Launch Control:
- Launch control enable switch: ACTIVE (Has to stay ACTIVE at least till step 5 inclusive)
- Mode: Drive or Manual
- Gear: 1 or 2
- Brake switch: ACTIVE
- Pedal position sensor: above 70%
- AT THIS POINT GCU IS IN LAUNCH MODE and uses LAUNCH CONTROL PRELOAD table. GCU will now output LAUNCH CONTROL STATUS (1024).
- To launch the car simply RELEASE BRAKE PEDAL, GCU will move from LAUNCH CONTROL PRELOAD table to actual LAUNCH CONTROL, and change LAUNCH CONTROL STATUS output to 0.
- To abort launch control strategy release throttle below 70%. Launch control status will change to 0. If LAUNCH CONTROL ENABLE SWITCH is not active GCU will use regular take-up. To go back to launch mode LC enable SW has to become and stay active at least until step 6.
LAUNCH CONTROL PRELOAD table defines pressure used to pre-load the drivetrain during launch scenario. Pre-loading greatly reduces shock and improves launch quality. Please keep in mind that overpressurizing may lead to clutch damage/burning, please have professional and experienced tuner set it for You if You’re not sure how to do it. Values of table output is control level similar to OL values used in the past. We recommend testing relation between control signal and actual clutch pressure on light loads and for short periods of time.
Example table below:
In this example engine LAUNCH CONTROL rev limit is set to 4000 RPM, but retard/cut (active) phase starts 500 RPM sooner. Once all conditions have been fulfilled to enable LC GCU streams LC flag received by ECU that enables LAUNCH REV limit. We want engine to spin freely ASAP up to launch zone and then pre-load the drivetrain. In LC active zone pressure used has been raised a bit to pre-load the drivetrain lightly. Values in the example above resulted in around 3 bar of clutch pressure (loggable via datalogger channels). As soon as brake is released those values are no longer used and GCU controls the launch in Closed Loop.
Make sure automatic tables (if used) are set to proper shift point taking launch RPM into consideration. While LAUNCH MODE is ACTIVE, AUTO UP SHIFT and DOWN SHIFT are disabled until brake is released.