Car in the movie Grease?

Question

I was watching the movie Grease the other day and my mother said that when she was in high school her boyfriend had a car that was like the black one with the flames coming out of the tail pipes. How did they make the car do that? Wasn't it dangerous?

Answer 1

When fuel is not properly exploded in the cylinder it goes down the exhaust system and explodes from the heat. The movie thing is just movie magic.

Answer 2

You can do it by dumping fuel into the exhaust and it naturally ignites in air. But a high performance car will do it all by itself.