[youtube https://www.youtube.com/watch?v=_oNA8zytUZQ&w=560&h=315%5D
Here's a turbo BMW on a dyno in a shop. To many people this might look like extreme backfire or some sort of crazy security measure - because who would drive off in a car that sounds like it's constantly exploding? However, it's really what's called an anti-lag system which is used on turbocharged engines to minimize turbo lag on racing cars.