What launch control does
When you launch a car by hand, engine speed at the moment the clutch or transbrake lets go is never quite the same twice. Launch control fixes that. It adds a temporary RPM limit that's only active while you're staged, so you can hold the throttle down and the engine sits at a steady speed. Alongside that limit you can adjust fuel and ignition, which on a turbo car is how you build boost before the car moves.
The limit's RPM, the fuel and timing changes, and the wiring each have their own pages: LC end RPM, LC fuel correction, LC ignition advance and LC wiring. This page covers the main settings that decide how the limit works and when it's allowed to arm.
Launch control is hard on hardware. Holding an engine on a limiter, especially with retarded timing to build boost, can overheat the engine, exhaust and valvetrain. The shock of a hard launch also loads up the transmission, driveshafts, diff, clutch and crank. This feature is for experienced users, and we recommend keeping sessions on the limiter short.
The settings
| Setting | What it does | Our advice |
|---|---|---|
| Cut Method | Chooses fuel or ignition as the way the limit is enforced. Hard or soft cut follows whatever the main RPM Limiter uses | Decide on the main RPM limiter cut type first, since launch control borrows it |
| Enable Coolant Validation | Makes coolant temperature a condition for arming | Turn it on. There's no good reason to launch a cold engine |
| Min Coolant Temp | Coolant must be above this before launch control will work | Set it to normal operating temperature |
| Enable TPS Validation | Makes throttle position a condition for arming | On, so launch control only acts when you're committed on the pedal |
| Min TPS | Throttle must be above this for launch control to be active | High enough that part throttle driving never triggers it |
| Enable Vehicle Speed Validation | Makes road speed a condition for arming | On, if you have a reliable speed signal |
| Max Vehicle Speed | Launch control only works below this speed | Low: just above a crawl, so it can't hold the car back once it's rolling |
Why the validations matter
Each validation is a gate, and all the gates you enable must be open before launch control does anything. Without them, a switch left on or a staging button pressed at the wrong time could hit the limiter in the middle of a pull. We'd rather launch control fail to arm now and then than activate when it shouldn't.
For the bigger picture of how launch strategies fit together, see how launch control works.
