Launch control is used to help maintain better traction and reduce wheel spin from standing starts.


It works by limiting the RPM to a user set amount by retarding the ignition timing as well as cutting ignition events. This can sometimes be referred to as a ‘2-Step Limiter’.


The ECU can be trigger to utilize launch control via a clutch switch, and then either use an in-line manual toggle switch to enable it, or, for more advanced applications, use a Vehicle Speed Sensor (VSS), (ideally on an undriven wheel) to disable the launch limiting once the road speed reaches a certain speed.


On plug-in applications, where the vehicle supports it, the clutch switch and VSS will already be connected and configured via the default base map. To add a manual override switch, simply place a toggle switch in series with the clutch switch, such that the signal can be ‘interrupted’.


FW 3.8+ VERSIONS


If you are using Firmware 3.8 or above, then you will have access to a more complex launch control module. The launch control settings will look as per the below once all of the relevant tables have been opened:



The following details what each setting relates to:


Enabled Yes/No - overriding enabling state, usually set to No for tuning on the dyno, then Yes when L/C begins to be setup.

Source - Digital Pin (use the Digital Input assigned to "Clutch Switch", or Analog Pin if you are using an Analog channel as a button input.

Switch Active State - Determines if 5V or 0V at the chosen input means on or off.

Cut Mode - Choose how the ECU should limit engine torque.

Arming Time - The time in seconds the switch has to in its Active State before Launch Control starts to take effect - Zero to disable the delay.

Max VSS - this is the maximum Vehicle Speed before Launch Control is disabled - Zero to disable this.


The following tables are also used for Launch Control:

Launch Ctrl VSS RPM Limit - This 2D table determines the RPM you would like the engine to hold given a Vehicle Speed - used to "ramp up" the RPM as the road speed increases.

Launch Ctrl Injection Trim - Use this table to trim the injection duty based on RPM and Throttle Position (i.e 1.12 would add 12% of fuel to the base fuel)

Launch Ctrl Ign Mod. - Use this table to modify the ignition timing based on Throttle Position and RPM (i.e -3 would take 3 degrees from the final ignition timing).


VSS Limiting is useful to allow full RPM sweeps even with the clutch depressed, i.e when down shifting at high speed. Otherwise, an in-line switch to the clutch switch will be needed to disable launch control, and hence stop the RPM being limited during gear changes.


Example of using a toggle switch to "Activate" and then a clutch button switch to trigger launch control:




LEGACY FIRMWARE VERSIONS DETAILED BELOW


The below illustrates the Launch Control/ALS configuration driver (Under the ‘MOTORSPORT’ node):

Set the ‘Switch Active State’ such that when you apply the clutch (ensure your in-line toggle switch is ON if you have fitted one) the ‘LC/ALS Switch Status’ reads ‘On’. Also, set LC Enabled to ‘Yes’.


Now you can set the RPM, (shown here set to 3,000), to be whatever you prefer the engine is limited to whilst in Launch Control mode. Now, when you depress the clutch, the engine will be limited to this speed, so you can apply wide-open-throttle and ensure any turbo-charging is sufficiently spooled - also it makes launching more repeatable as the RPM is always fixed as opposed having to ‘find it’ with the throttle. As soon as you release the clutch, the RPM will be allowed to rise as normal, UNLESS you have a VSS Limit set, in which case, the RPM will still be locked at the Launch RPM until your VSS passes the setting (in the picture, it’s set to 5mph). Setting the ‘VSS Limit’ to zero will mean the system only uses the clutch switch to enter Launch Control, and will ignore the vehicle's speed.