I ran across this blog site where someone built a Pinewood Derby car with two CO2 cartridges on it, and then made a simple mechanism that would puncture the cartridges as the gate went down. Thought some of you might want to take a look at it (click on the pics for a better view):
http://crazyallenmoments.blogspot.com/2 ... derby.html
-Nitro Dan
CO2 Powered Pinewood Derby Car
CO2 Powered Pinewood Derby Car
Take good and make it great. Take fast and make it faster. Performance drives success!