C02 will NOT do the same thing as nitrous. C02 will EXTINGUISH fires...nitrous (N20) HELPS fires burn like oxygen does and it comes out of the bottle at about negative 127 degrees F. This cools the intake air charge by about 65-70 degrees by the time the nitrous gets into the engine. You MUST HAVE an extra fuel source to run nitrous, just running the carb rich will work, but not for very long.
a 350 horsepower engine with an intake temperature drop of 70 degrees f, would gain about 25 horsepower just by the cooling effect. add nitrous and the nitrogen buffers the cylinder pressures which leads to more controlled combustion and huge horsepower increases. the added fuel that is injected into the cylinders is burned rapidy by the help of nitrous, with a very low air intake temprature charge. an engine that is sucking in cold air will make more horsepower than an engine sucking in hot air. but you have to have added fuel to make big hirsepower increases. ANY engine will make more horsepower when the air temp outside is -30 F rather than 80degrees F. the benefit of nitrous is the abilty to add more fuel that what the carb supplies, and the nitrous is like spraying pure oxygen onto to a blazing bonfire.
In order for nitrous to truly be effective, and for your engine to live, you have to add extra fuel besides what is being sucked into the engine from the carb. you have to have a total secondary fuel source (like a solenoid with a jet in it, and fuel under pressure that can be injected into the engine).
3000 psi of pressure is WAY too much pressure to shove into one of these little 2 stroke engines.
a typical nitrous set up on a v-8 is injected into the cylinders at only about 800 psi, which is set using a regulator.
your idea will never work.
if the 3000 psi doesn't blow the head off the cylinder, the 3000 psi will just stop the piston in it's tracks and probably bend the connecting rod.