Re: G4 xtreme launch control

[Marios Theodosiou]

How can i set up the launch control for deactivating via vehicle speed sensor

[Simon]

Launch Control is designed to allow for more consistent stationary launches.  This mode of Launch Control controls the rate at which engine RPM increases to minimise wheel spin.  To do this, the ECU needs vehicle speed information.

 

  This mode of Launch Control employs a vehicle speed dependent RPM limit to reduce wheel spin.  The required RPM limit at each vehicle speed will only be found by testing.  This means that in all cases, a vehicle speed sensor (on a non driven wheel) must be installed and configured.  A Digital Input must be set up as Vehicle Speed.  The Digital Input used for Vehicle Speed must be specified under DI Speed Channel.

 

The following adjustments apply to Launch Control Mode #1:

 

·	Activation Control - This is the number of the Digital Input used to arm/disarm the Launch Control function.

·	DI Speed Channel - This is the number of the Digital Input used for vehicle speed measurement.

·	Disarming Speed - Launch Control will be disabled when the vehicle speed is above this value.

·	Launch RPM Table - This table specifies the RPM limit value used at a given vehicle speed.  Refer to the Limit Mode adjustment for information on how the RPM limit is applied.

 

The following adjustments apply to all Launch Control modes:

 

·	Ign Retard Mode - This specifies the way ignition retard is applied to the current ignition timing value.  Options are:

o

Degrees - Ignition timing is altered from its normal value by the number of degrees specified in the Launch Ign Trim setting.  E.g. If the normal ignition timing is 12 degrees BTDC, -30 degrees Launch Ign Trim will make the ignition timing 18 degrees ATDC while launch control ignition trim is active.

o	Percent - Ignition timing is altered from its normal value by the percent specified in the Launch Ign Trim setting.  E.g. 300% will alter the timing from 10 deg BTDC to 20 deg ATDC while launch control ignition trim is active.

o	Degrees Absolute - Ignition timing is altered to the value specified in the Launch Ign Trim setting.  E.g. -35 degrees will make the ignition timing 35 degrees ATDC while launch control ignition trim is active.

·	Ignition Retard Table Mode - This specifies whether the ignition retard value is a single value, or is a 3D retard table.

·	Activation Control - This specifies the control channel to arm launch control.

·	Fuel Trim Table - This activates a 3d fuel trim table, this is useful for injecting extra fuel to keep exhaust gas temperatures down.

·	Launch Ign Trim - The amount the ignition is altered when Launch control is active.  The way this value is applied depends on the Ign Retard Mode.

·	Ign Trim Activation %TP - Ignition Trim is applied when the throttle is opened past this value AND the RPM is greater than the Ignition Trim Activation RPM.

·	Ign Trim Activation RPM - Ignition Trim is applied when the RPM is greater than this value AND the throttle is open further than the Ignition Trim Activation %TP.

 

Further more, there are adjustments relating to the limiting system used by launch control.

 

Link G4 ECUs use a progressive limiting system.  The limiting systems progressively cuts fuel and/or ignition over a specified limiting control range.  Throttle position is also taken into consideration to provide more aggressive limiting at high throttle positions.

 

Limit Mode

The limit mode is used to turn the system on and off. When turning the system on, there are four available limit methods.

·	OFF - Limiting is turned off.

·	Ign % Cut - An ignition only progressive cut.

·	Fuel % Cut - A fuel only progressive cut.

·	Ign+Fuel (Rotary ONLY) - A special ECU controlled fuel and ignition limit for rotary engines only. MUST use Sequential Staged Injection Mode.

 

Note: In a setup using Staged Group Injection, ALL fuel limiting is locked out, the only limiting option available is ignition.

Note: In a setup using Group Injection it is recommended for smooth limiting that ignition cutting is used. A hard fuel cut can be applied if required.

Note: In a setup using Auxiliary Injection only use Ign % Cut limiting.