Ok, here's the scoop you all need to run NOS. Your NOS pressure has alot to do on how the system will work. Most systems tell you to run with 950-1050 psi,low ambiant temp will act like you're running rich,get a heater and keep the temp up so that you are able to keep the pressure between the temp specified by your manufacture. All jet settings specified in your instruction are given to you as a safe set-up,as in not being to lean for the H.P. you're looking for. As for your purge, locate your purge valve as close to your nitrous solinoid as possible, this is to insure that you are getting rid of all the "gas" and using LIQUID as the system is suppose to. Also remember start small and work up. AS the H.P. goes up you will need to use higher octain fuel and retard the timming as a thumb rule 2-3 degress for every 60 hp added thru the system, Stay ahead of your bottle pressure, use as big of a bottle as you are able to store safely. Remember lean is mean but it can cost you lots of money and headachs if you go over the line, being a little "FAT" is always safer than thinking you know more than you do or listening to your buddy on what jetting you need, go by your set-up sheet an go from there, have fun