Originally Posted by Injuneer

Rich.... the problem I have is the "critical point" of nitrous at 1052psi. Above that pressure, according to the definition of the critical point, the nitrous can exist as both a liquid and a gas. That amorphous state may actually cause flow to NOT increase in direct proportion to the square root of the pressure difference (nitrous pressure - manifold pressure).

The concept of critical point is still little fuzzy to me, and I've asked some genuine ChE's to explain it to this dense ME, but so far no luck.

Originally Posted by gforcejunkie

i know a few people who dont get a purge and just loosen the fitting at the solenoid i dont recommend it but it works. but as long as you leave the bottle on there should be no reason to even use the purge. i always purge it if i turn off the bottle.

Originally Posted by Injuneer

Leaving the bottle open all the time can damage the seats in the solenoids.

You should purge if you are after consistancy and max performance... its possible to get hot spots in the nitrous lines, particularly in the engine compartment, and you end up with a bubble of gaseous nitrous in the end of the line, delaying the hit.