With the example I gave of a cheap turbo setup (I don't think an expensive blow through carb was included in that) and the example you gave of a nitrous setup cost wise, I would like to address this "myth" that nitrous is one "cheap horsepower" and "easy"... "BULLCRAP!!"
I strongly believe this is why people blow their engines up.. someone don't know nothing about it buys some generic kit and think he's going to set the world on fire... First the generic kit comes with nothing for the fuel side except a fuel solenoid... Not knowing any better just puts a t fitting in his fuel line after the pump (hopefully after the pump and not before LOL) and runs it to the fuel side solenoid... Easy... (Likely improper fuel pressure, no fuel pressure gauge, no low pressure cutoff switch, no filter, definitely running whatever octane gas is in the tank, ECT...)
Most generic kits don't come with a pressure gauge for the nitrous bottle, so who knows what the pressure is???!!..
Most kits only come with a full throttle activation switch which means any time you're at full throttle it activates both solenoids or should... Hopefully this cheap kit comes with an arming switch so you can shut that off...
And the most important thing to keep your motor from blowing up is never addressed in one of these cheap kits..
Timing retard... If you're smart enough to take this into consideration without a timing retard mechanism of some sort you're going to have to adjust your distributor absolutely every time you use nitrous... Or continuously try and drive around with retard timing..
I would say if you're going to do it right A good rule of thumb would be to double at the very least the cost of one of those cheap kits... Long before the bottle is filled... and once you accumulate this cheap kit and all the stuff to make it work right if you think it's just as easy as slapping a bottle in the trunk in my opinion you've lost your marbles....
Did someone mention the price of a Purge kit? LOL...
Some valid points, but some I believe are exaggerated. Let's say I agree with all the precautionary extras on a serious use with big horsepower gains. then we can move onto why I don't run all those extra parts that add cost.
First, a pressure gauge on the bottle fitting tells you pressure only. Does nothing for bottle liquid content, which is only accurately measured in weight. A 10 pound bottle carries 10 pounds of liquid nitrous. That same bottle that is 5 pounds light is about half full. Also, generally speaking, nitrous bottle pressure will be about 10psi for every 1 degree of fahrenheit of bottle temperature. So a 90 degree bottle can pretty safely assume a 900psi bottle pressure, given a decent amount of remaining liquid. That's why you generally heat the bottle to 90 degrees, give or take, depending on your tune. Now, it is easier to read pressure from the driver seat when using a purge system to get back down to 900psi if the temp/pressure has gone too high.
Now, purge kits. The reason I don't use a purge kit is because on a 250 horsepower or lower factory jetting tune up it's simply not worth the cost to me. I already set my bottle temperature before I go to make a run, so only benefit would be to purge the expanded gas out of the feed line all the way to the solenoid. To that, I just manually crack the line loose at the solenoid or do a quick dry hop with the system activated.
Next, teeing into the existing fuel line. Fuel system needs are basically based on your expected fuel consumtion of the entire packaged, correct? If I am making three hundred horsepower naturally aspirated with a carb, why in the world would I run something like a giant Aeromotive 1000 series electric fuel pump. Screw that. Put on a mechanical fuel pump, using the stock fuel line setup, and just the make sure the fuel pump delivers enough galons per minute to maintain a 300hp setup. Now if I want to make 450hp with a carb, regardless if its with nitrous or naturally aspirated, I can still put on a nice mechanical fuel pump rated to supply enough fuel for that power level, then it is safe to tee into the existing fuel line going to the carb from the pump. And the pump only puts out 5 or 6 psi, or if I already have a regulator to get that pressure, I am good to go.
Fuel octane is another one that is often overrated. If that same 300hp naturally aspirated setup only has 9 to 1 static compression, and I have a camshaft that is keeping the cylinder pressure in a reasonable range, reasonable enough to run my same octane up to 450hp, then why not stick with that same fuel octane, since it's cheaper. It's the same thing as the cruise night guys that run racing fuel just so it has that smell when he pulls into the show. Not needed.
I would never bag on anyone for overbuilding the system if that is what they want to do and can afford it, but by repeatedly saying everyone running nitrous needs all this extra crap is just adding to the whole negative stigma surrounding nitrous use. I don't intend this overly long post to be negative toward anyone, but as it pertains to this particular thread, this is how I do it and why i do that way.