Nitrous oxide is stored in a liquid form in a pressure tank rated to 1800 psi, at room temperature and normal atomospheric pressure (14.7 psi) nitrous oxide is in a gaseous state. To use nitrous oxide it needs to be in a liquid state and that means it has to be under pressure. At 80* F it takes 865 psi to keep nitrous oxide in a liquid form.

Most nitrous systems on the market today are calibrated to operate at 900 to 1000 psi bottle pressure, A bottle heater and pressure gauge are a must have to properly tune your nitrous system.

Now i will make a ststement that some people will want to argue about. Nitrous oxide does not make power, it will not blow up your motor. Thats not what you have been told is it. Only fuel can make power, by releasing it's stored BTU's, but fuel alone will not burn, it needs oxygen combined with it in the proper air to fuel ratio to burn, this is where nitrous oxide comes into play. Adding nitrous oxide to your engine allows more fuel to be added than the engine can draw in on it's own. Just like bigger throttle bodys, cams, headers and forced induction systems. With that added extra air more fuel must be added to obtain the proper A/F ratio. Nitrous oxide is an oxidizer, it allows a fuel to burn. if you do not give it enough fuel it will find it's own fuel source, in our case that source will be the aluminum in your pistons, remember, solid rocket fuel is made of aluminum and oxygen, these two compounds burn very well together, so always make sure you have enough fuel to support the nitrous flow.

Is nitrous safe All of the horror storys you hear about nitrous blowing up engines have two root causes. #1, Lean A/F ratios from improper tuning or faulty under sized fuel systems. If your engine is making 250 hp and the fuel system is barely keeping up with that hp level it will not provide enough fuel to support another 100 hp from nitrous, and back to our rocket fuel analogy your pistons will be used as that fuel. Reason #2, Increasing hp levels highrt than your engine can withstand. A stock engine is only going to be able to hold about a 40 or 50% increase in power levels before you drive over your crank shaft, A 200 hp stock engine should be able to handle another 100 hp for a total of 300 hp. Try to go over the 50% limit on a stock motor and it will have a much shorter life span. Large power increases need stronger parts, forged piston and rods, high strength head studs and rod bolts, all the things you would use in a racing engine. So your friends car that blew up the next day after installing nitrous blew up because your friend improperly tuned it or got gready and put the big jets in a stock motor. It wasn't the nitrous, it was the actions your friend chose to make.

We will focus manily on single nozzle systems for computer controled EFI engines. 150 hp is the highest power level safely obtained with a single nozzle. Also we will only be dealing with what is called a wet system. One that injects both nitrous and fuel together. Dry systems that inject only the nitrous and use added fuel pressure or longer injector pulse widths to make up the needed extra fuel have limited hp levels and i don't recomend them, they tend to be unreliable and harder to tune.

System set up WE will focus on street driven cars only, not track or race cars. The bottle is to be mounted in the trunk only. secured by the supplied brackets in the position recomended by the kit maker, the safety blow off tube must be installed and routed out side of the passenger compartment of a street driven car. The temperature inside the car can very quickly rise above 120* F when left parked in the sun, this will cause the bottle pressure to rise enough to burst the safety relief disk in the bottle valve, and all of the nitrous in the bottle will vent out. Into the car if you don't have the blow off tube installed. Nitrous sprays at -127*F, it will freeze burn you very badly, and cause a vapr cloud that could blind of suffocate you, so install the vent tube for your own safety.

The supply line from the bottle to the solenoid valve is a specil high pressure line, run it under the car not through the inside of the car, running it along side of the cars stock fuel line is a good place to route the supply line. All wet nitrous systems will use two solenoids, one for the nitrous and one for the fuel, conect the nitrous supply line to the nitrous filter and then to the nitrous solenoid. The fuel solenoid will be supplied ether from a tap on the fuel rail or by a t-ing into the fuel rail.The nitrous solenoid is a high amperage solenoid used for high pressure gas, don't mix them up. They will be labeled n2o and fuel. Mount the solenoids where they will not be subjected to extreme heat. From the solenoids outlet sides you will run smaller #3 AN lines to the nozzle, the shorter these lines are the harder or more forceful the hit or engagement of the power will be, the longer the lines are the softer the engagement will be. For a street car a softer hit will work better, a hard hit can cause the tires to spin or brake drive line parts like axles.

Activation system This is the electrical part of the system that turns the nitrous on. A basic wiring plan will include an arming switch, throttle switch and a 30 amp relay, more advanced setups will have rpm activated window switches to turn the system on and off at preset rpm points, like 3000 to 6000 rpm, do not engage the nitrous below 3000 rpm's, engaging the system at to low of an rpm can result in a back fire through the intake manifold. at the low hp levels developed with a single nozzle system engine damage from a back fire is unlikely but not unheard of. Only use nitrous at wide open throttle.

Timing and spark plugs Every 50 hp of nitrous injected needs a 2* reduction of ignition timing. On EFI engines this sometimes can not be easily done, if you have no way of backing off the timing do not exceed 75hp levels. Do not use after market computer chips that increase timing to improve hp when using nitrous. Spark plugs should be one to two heat ranges colder for nitrous, to hot a plug can cause detonation and to cold of a plug will foul. A plug needs to be hot enough to self clean but not so hot that you get detonation. The electrode and ground strap of the plug is also very important. many modern efi engines use a plug with a long reach electrode and a thin narrow ground strap, the ground strap can become so hot that it glows red hot at all times under wot with the added heat and cylinder pressure of nitrous, causing preignition. Try to use a plug with a wide, thick and short ground strap so the heat can be dissipated faster.

Tuning guide If the kit you are using is vehicle specific you can be sure the jets that come with the kit are tuned for your engine at the hp levels stated, most kits are just a little on the rich side for safety, and you can fine tune it for max power, but one size smaller fuel jet or 50 psi higher bottle pressure is probably all that will be needed. If it is a universal kit and you need a baseline setting to start with, the maker of the kit can guide you or you can find a site on line. A common misconception is that a 100 hp kit from a v 8 car will make much more than 100 hp on a v 6 or 4 cylinder car. That is not true, 100 hp is 100 hp no matter if it's on a 500 cu.in. big block or a 5hp lawn mower engine, of course the lawn mower engine will blow up if you try to put 100 hp more to it. but the power levels are the same regardless of engine size, differant kits come with differant size jets because they are taylored to a specific vehicles fuel pressure. A 5.0 mustang uses less fuel pressure than a pontiac GTP. The nitrous jet corresponds to the oxygen or cfm rating and the fuel jet represents the BTU levels. You can pick a hp rating using the nitrous jet and tune the fuel jet to match. A #41 nitrous jet will always be for a 70hp level, but the fuel jet will vary depending on the system fuel pressure. some engines will make a little more power than the kit rating, such as turbocharged or super charged, because the n2o has a super cooling effect on the intake charge giving some VE improvement, but it won't be 100% like you hear on the internt, more like 20% for some engines, i made 100hp on a 75 shot in an srt-4

Tuning checks Always check the spark plugs, all of them, not just the ones that are easy to get too. With a single nozzle system some cylinders could be richer or leaner than others, you have to tune to the leanest cylinder, even if that means some cylinders will be on the rich side. Plugs that have a salt and pepper or specleled look are lean. those speckels are aluminum gas vapor from your pistons. Bluish or rainbow look to the ground strap indicates a lean condition. Sooty or black plugs indicate a rich condition. The plugs should look the same as when your not using nitrous, a light tan or brown color. A ground strap that looks rounded off and no longer has a sharp square edge indicates to much timing, if you have no way to retard timing, go to a higher octane fuel or reduce the power level by using the smaller jets. A surging or lazy feel to the engine indicates a rich condition, also black smoke out of the tail pipe, or back firing in the exhaust system is a rich condition. Poping or back firing in the intake system indicates a lean condition. If any of these symptoms occur, abort the run and find the cause, do not try to drive through a flat spot or engine miss, nitrous builds heat and pressure to fast to take chances, find the problem first, before you damage the motor.

Here is a list of common jet sizes for two of my favorite engines. The L67 buick 3.8l supercharged v 6, and the dodge 2.4l dohc turbo charged 4 cylinder from the srt-4. Notice they are the same, even though the engines are totaly differant in type and size, they both use a very similar fuel pressure, so the base line starting point for both engines is the same, These settings are based on the stock fuel pressure and a 900 psi bottle pressure.

These jet sizes are a little on the rich side for safety and can be fine tuned for max power.

This is not ment to be an all inclusive bible to nitrous oxide, just a starting point. there are many other aspects to nitrous, like multi stage system, direct port system. purge valves, nitrous controlers and much much more. This is just ment as a primer to take away some of the fear of nitrous and get you started on a path to power, i have left out lots of information, you could write a book on what has been left out, This is about long term usage with out hurting your engine, it is quite conservative so you can run nitrous safely. oh yeah, it's not called naws, nos is a brand name and only a punk ricer would call it that.

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