Launch Control and No Lift Shift Configuration

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Steve @ VersaTune
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Launch Control and No Lift Shift Configuration

Post by Steve @ VersaTune »

For those who are unfamilliar with Launch Control and No Lift Shifting, here is a quick overview of how it is implemented in Versatuner and how to customize it for your vehicle.


Stock rev limiter bahavior (NLS/LC disabled)

The stock rev limiter is set to 6700 RPM under normal operating conditions. Under certain conditions like stuck throttle in neutral or certain temperatures, it is set to 5500. When the engine RPMs hit 6700, the ECU cuts fuel for a short duration. If RPMs drop below 6700 and the over rev fuel cut timer is expired, then normal fueling resumes. Normal fueling will not resume until the RPMs drop below 6700. These non-LC/NLS rev limiters are set in Tune Editor like the other tables.


The use of Launch Control/No Lift Shift allows three different rev limits based on clutch position, vehicle speed, and accelerator pedal position. Launch Control/No Lift Shift is enabled and configured in Tune Customizer which is accessed from the Settings button on the Home tab of VersaTuner. When you enable Launch Control/No Lift Shift, it enables the default launch control and no lift shift behavior. It can be customized to your preferences using Tune Customizer.


Normal behavior

When the clutch is not depressed, as in normal driving, the normal rev limiter (6700 RPM by default) applies.


Launch Control (LC) rev limit behavior

The default LC behavior is active when the clutch is depressed, vehicle speed is below 9 km/h or 5.6 mph, and the accelerator pedal position is greater than 98%. While these conditions are met, the LC rev limiter will be active (4000 RPM by default). This allows you to build boost at the starting line for harder launches and a short rollout with the revs limited to help with consistent launching. All of these parameters are configurable in Tune Customizer. If all three of these conditions (clutch, speed, APP) are not met, the normal rev limiter or NLS rev limiter will be used depending on clutch position.


No Lift Shift (NLS) rev limit behavior

The default NLS behavior is active when the clutch is depressed and the vehicle speed is greater than the LC speed threshold (9 km/h or 5.6 mph by default). Under these conditions, the NLS rev limiter is active (5000 RPM by default). This allows you to keep the accelerator pedal down while shifting and not over rev the engine. This alllows the turbo to stay spooled during shifts resulting in immediate power in the next gear. The NLS parameters are configured in Tune Customizer.


Please note that both Launch Control and No Lift Shift create significant additional stress on the engine and driveline. Be certain that you have the necessary upgrades to handle the additional stress.
mituc
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Re: Launch Control and No Lift Shift Configuration

Post by mituc »

Is it possible (or does it even make sense) to implement LC by controlling the throttle opening rather than cutting the ignition?
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
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Steve @ VersaTune
Lead tuner
Posts: 1157
Joined: March 29th, 2010, 12:58 pm

Re: Launch Control and No Lift Shift Configuration

Post by Steve @ VersaTune »

LC uses the built in rev limiter, which uses fuel cut, not ignition cut.

It would require a tremendous amount of code that would require tuning on every car to do it with throttle control.
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