OK, this is what one of my friends did. You put a spark plug in your exhaust pipe and wire it up with a converter that will convert 12 volt to a higher voltage that would make a nice spark on the spark plug just like it would normally in your engine. Run this power wire to a push button switch near your steering wheel. To get the extra fuel in the exhaust to spark, he unplugged his battery for 24 hours. When he plugged it back in, he drove his car like hell all day. The computer in his car then programmed itself to give it that much fuel 'cause it figured that is how it would always be driven. Now all he has to do is be giving it gas and tap that button switch to shoot a flame.
If this has already been explained by someone else or isn't the "technical" way to do this, don't get all up on me. He drives a Saturn and I'm just telling you how he got the effect to work. I know it's not the correct way, but it was easy.
