Quote Originally Posted by Unkle Fuzzy View Post
He is using an anti-lag system (ALS). He presses a button with his left hand and the engine starts sounding weird. The ALS causes late ignition and raw fuel/air to enter the exhaust where it burns driving the turbo charger to make boost even though the engine is unloaded. You can hear the turbo spooling when he presses the button.

Probably his exhaust manifold/turbo/down-pipe let go as drive side pressures can exceed 2.5-3 times boost under normal conditions.

Most of the engines setup for this type of launch sound like a machine gun firing. There was a video on youtube where police heard the sound and started harassing the guys at a tuner shop about illegal weapons. Several patrol cars arrived and when the mechanic demonstrated the system for the police, the officer who originated the incident was laughed off of the scene.
I suppose to an untrained ear such as a patrol officer may have if he is not a combat veteran the echo of the (ALS) possibly could sound like an automatic weapon.
We used to make tuned expansion chambers for 2cycle motorcycles, once they started to degrade over time they could take on a sound much the same way, but their sound was more like the rapid firing of a Colt 1911 .45 automatic