Launch control is a means of allowing the ECU control of the engine power output during the race start phase to provide the best possible traction from the start line. The driver maintains full throttle at all times, even when stationary with the clutch depressed. As soon as the car begins to move the ECU reduces power output by first retarding the ignition advance and if this still does not control the rpm it will cut one or all cylinders as required to keep the engine RPM to the limits set in this section. An un-driven wheel speed sensor is required (hall effect wired as the wiring diagram) and a push button switch on the dashboard to activate the system. The driver comes to the start line, depresses the clutch and engages gear. The launch control button is pressed (the gear change light will flash repeatedly to signal that all is working) and presses the throttle fully open. The engine will be held at the start line rev limit as set below. This requires the use of the hard cut limit (done automatically by the system) so the engine sounds very peculiar. When the clutch is released the ECU will control the engine revs to maintain the target slip percentage until the turn off speed is reached. After this time it will allow the engine to run free until the button is pressed again.
1 LAUNCH CONTROL ON
This is main engagement switch. When set to N nothing will happen. When set to Y when the button is pressed the system is armed and the gear change light will flash. It will continue to flash until either the turn off speed is reached or the button is pressed again.
2 UNDRIVEN WHEEL PULSES PER ROTATION
This is the number of pulses the hall effect sensor sees i.e. if using the brake disc the number of holes in the disc.
3 UNDRIVEN WHEEL DISTANCE PER ROTATION (in mm)
Self explanatory either measure it or use 3.142 x diameter.
4 SPEED TO TURN OFF (in kph)
Undriven wheel speed to turn off the system. Normally set to the maximum speed in first gear.
5 DISTANCE PER ENGINE ROTATION (in mm)
Distance the car travels in the start gear per rotation of the engine.
formula :- distance = (wheel diameter x 3.142)/(fist gear ratio x final drive ratio)
example (584 x 3.142)/(2.57 x 3.89) = 184 mm
NB. if you change the tyre diameter or the first gear or final drive ratio this needs changing!
6 MINIMUM RPM
This is the absolute minimum rpm allowed by the control. At this point all retard etc. is removed as quickly as possible so that the engine does not bog down.
7 STARTLINE RPM
This is the RPM that the engine is held at while using full throttle on the start line. It is also the rpm that is targeted initially immediately the car starts to move. As the speed increases to the point that the target RPM is above this figure the engine is allowed to go faster.
8 PID GAINS
These figures control the mathematics of this function. Leave as originally set i.e. 80,20,0 unless you have problems, in which case contact us.
9 TARGET RPM TO SOFT LIMIT/HARD LIMIT
The system will initially try to control the engine using ignition retard. If this is not enough then first the soft limit will be invoked at this RPM above the target, secondly the hard limit will be invoked. The hard limit is very rarely hit in normal circumstances.
10 LIMIT RPM WHEN BUTTON PRESSED ONLY
With this option no sensor is needed and the rpm is limited to the start line RPM as long as the launch button is pressed.
11 SET START RPM WHEN BUTTON FIRST PRESSED
The engine start line RPM is set at whatever RPM the engine is doing the instant the launch activation button is pressed.
Please remember that the settings for wet and dry situations are unlikely to be the same. Also in the wet some modulation of the throttle pedal will improve the performance.
The gear shift cut section allows the ignition to be turned off when a gear change is in progress with a sequential gear box. The signal is provided by a switch, usually mounted on the gear lever.
1 GEAR SHIFT CUT ON ?
Yes no answer, is this function active.
2 SHIFT CUT DELAY TIME
Time in milli seconds after the shift signal ends to continue to stop the ignition sparks. Used to allow mechanical settling of the gearbox after engagement. Consult gearbox manufacturer for a suitable figure.
3 NO SHIFT CUT BELOW THROTTLE
If the throttle position is below or equal to this figure then no engine cutting takes place. Used to allow engagement of first gear on the start line without stopping the engine!
4) DELAY ONLY
This ignores the time the button is pressed and just uses the delay from first contact
CHAPTER 26 LAMBDA TARGET MAP
Windows menu:- Other Map Settings/Lambda Target Map
This table contains the target air/fuel ratio for any point in the operating point of the engine. Minimum is 10/1 and maximum is 16/1. Manipulate as with any other 20 x 14 map. Its operation is governed by a check box in Lambda settings.