It only happens when you have a very rich condition with no cats and a very hot exhaust system.

On turbocharged or supercharged vehicles it happens when you shift, and the blow off valve/bypass valve vents into the atmosphere which causes a very rich condition and the hot exaust gases backfire in the exhaust and shot a flame.

On a vehicle with no cats, it usually happens when the a/f is very rich and you shut down ignition for a second (when you hit rev limiter).

I used to shoot flames all the time in my old 91 mr2 turbo in the canyons. Everytime I vented into the atmosphere I would see a huge ball of light behing me.

But the fake flame throwers are rice unless they are on old cars like the 32' ford roadsters.

 

never said i was doing it to a Z, can understand why you think so tho, still i think it looked good in the movie!

 

if you get that your car will be 2 fast and 2 furious