N2O runs fine just as long as you keep the air fuel ratio around the stoicheometric number 14.7:1 or a even better ratio 12.5:1 and not let it get lean. If you happen to hit the arm switch when the engine isn't running and purge nitrous into the manifold or cylinders, pull the plugs and crank the engine. Never hit it at idle. When nitrous goes lean, I have seen piston crowns melted into aluminum slugs, rods bent and intakes blown off. Purging nitrous only comes into play if want to put on a show at a stop light or if your running a really serious nitrous set up. Purging clears the lines and provides a fresh shot of N2O. Another myth running external fuel source, an oem pump can supply enough fuel for a 250hp wet system. The timing issue, usually 1 degree per 100hp, there are some people saying that by retarding the timing your negating the effects of the nitorous by dropping effective cylinder pressure. Nitrous is harmelss if used correctly, and as long as the cylinder pressure is kept with in load factor design limits. Meaning don't exceed the limits of the oem components. Automotive manufactures usually test there components to a 1.2 to 1.5 load factor, where as diesel engine manufatures test there components to 2.0 to 2.5, meaning that would be 2.0 times nominal load. The testing is over a given number of engine cycles.
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