something else aboiut spray(Nitrous Oxide) use...
1) if u use a staged system use one that addes additional spray with each stage, rather than flips over from one to another, even with the best auto retards u can STILL catch ur ignition in transistion from one retard set to the other and end up having a big bang and fireball jus as if u leaned out or lost adequate fuel supply, IE: if u want a total of 250bhp use maybe 50 to 100 for the 1st stage then add the remainder in ur 2cnd stage w/ seperate auto retards on both.
2) any internal combustion engine has what is known as a TEP or thermal efficiency potential controled by its physical size and the ambient atmospheric pressure it operates in, and THIS dictates how much power u can produce from said engine, the only way to exceed this is to increase the size of the engine and or the atmospheric pressure in the inlet such as turbo or supercharging, spray will NOT do this, it is a declining pressure application, IE: if ur engine has a TEP of say 700bhp and u make 600 of that on the mtr alone, u can spray all the spray u want n u'll only get another 100 bhp... its essentually a clean up to give u on demand what ya left in the mtr during ur build....
3) there is really no such thing as a nitrous cam grind, any came with low lobe center and sep numbers, and or moderate duration is goin to work well with spray since they bleed off LESS cyl pressure by way of shortening the amount of time in which BOTH valves are off their seats, known as OVERLAP. this is what ya want with spray since its a declining pressure application that does not increase atmospheric inlet pressure, in short u want as much of ur spray to stay IN the cyl once u get it in there as possible, cams with long duration and or or wide lobe seps n centers are not conducive to this.
Remember, tho rated in BHP what spray actually increases is TQ, IE: if ur sprayin 250bhp, no matter what rpm u engage ur system at, u get the whole of that 250, even if u engage it at idle, (which is a very dangerous thing to do, nitrous should b installed so as to b engage at nearly if not AT WOT!!!!!)
finally, to insure good and instant engagement of ur system USE A PURGE SYTEM installed as close to the nitrous solenoid or noids as possible.