Originally Posted by
nick-21
I knew that was how anti lag worked, but i thought launch control was simply like a fake rev limiter? i.e. you can mash the throttle with the clutch in and it will only rev to say 4k? Because you foot is on the throttle it would still be spooling the turbo?
It's not a lower rev limiter. It works by retarding the ignition at a set engine speed to a point where the engine will not rev any more. This means that the flame front created by ignition occurs that late in the cycle that it is still burning when the exhaust valves open. The energy created by burning the fuel then travels out and down the exhaust manifold, spooling the turbo. A lower rev limit doesn't really work properly as the engine isn't under load so the turbo doesn't spool properly.
ALS works in a similar principal but operates off throttle as opposed to on throttle (hence why you need an ALS valve to provide enough air to continue combustion after throttle closure).