Quote Originally Posted by crisis
The proximity of the tip to the extractor system will also play a part in making the tips unusually hot. Matra, how did I do?
For non-cat cars and normal fuels the flame at tip is more to do with the oxygen available.
Not a lot of air in the pipe so it won't burn.
It's true that shorter pipes mean hotter gas and more likely to self-combust on meeting air.

Local trade show had a new 'must have' for the boy racers
it was an injector into the tail pipe and a spark generator.
Screw it into the last couple of inches of the pipe, plumb the fuel to it, and wire it to a switch. Press the switch and it squirts a small amout of fuel and ignites it to get "realistic flames" from the exhaust
Kids in baseball caps all seemed to have one clutched in their hands !!!