How does nitrous work?
There are three points. First, nitrous oxide is comprised of 2 parts nitrogen and one part oxygen (36% oxygen by weight). When the nitrous oxide is heated to approximately 572 degrees F (on compression stroke), it breaks down and release extra oxygen, However, it is not this oxygen alone which creates additional power, but the ability of this oxygen to burn more fuel. By burning more fuel, higher cylinder pressures are created and this is where most of the additional power is realized. Secondly, as pressurized nitrous oxide is injected into the intake manifold, it changes from a liquid to a gas (boils). This boiling affect reduces the temperature of the nitrous to a minus .127 Degrees F. This "cooling affect" in turn significantly reduces intake charge temperatures by approximately 60-75 Degrees F. This also helps create additional power. A general rule of thumb: For every 10 Degrees F. reduction in intake charge temperature, a 1% increase in power will be realized. Example: A 350 HP engine with an intake temperature drop of 70 Degrees F, would gain approximately 25 HP on the cooling affect alone. The third point, the nitrogen that was also released during the compression stroke performs an important role. Nitrogen acts to "buffer or dampener" the increased cylinder pressures leading to a controlled combustion process.

What Concerns to people have with nitrous use?
Detonation is probably the biggest concern to most nitrous users. Detonation is the result of to little fuel present during combustion (lean) or to low of an octane of fuel. Too much ignition advance also causes detonation. What does detonation do? well think of a bomb going off in your engine, this happens when the once controlled little explosions in the engine happens at the wrong time with a more explosive mixture in the chamber than normal. Result? the piston goes through the roof, the crank digs a 5ft hole in the ground , valves and springs fly every where and a connecting rod hits you in the nuts as your engine generally explodes into tiny bits of molten metal. Most people have associated this with nitrous but detonation happens on turboed, supercharged, even your average car just cause it felt like it. The proper setup will prevent this from occurring. Nitrous has caused some of the most spectacular explosions I have seen as well through a build up of pressure. Remember in the bottle nitrous is liquid and can get up to thousands of PSI in there, bottle warmers left on by accident have caused some serious problems and major damage. Nitrous has to be handled and treated accordingly, if treated with respect you will find yourself with some awesome gains!
Can I use nitrous with a Supercharger or Turbo?
Absolutely! In turbo applications, turbo lag can be completely eliminated with the addition of a nitrous system. In addition, both turbo and superchargers compress the incoming air, thus heating it. With the injection of nitrous, a tremendous intercooling effect reduces intake charge temperatures by 75 degrees or more. Boost is usually increased as well; adding to even more power.

Can I use Nitrous on a high mileage engine?
This depends largely on the actual condition of the engine components. Mileage is not an indication of engine condition. Some low mileage vehicles are technically worn badly. Stop Start motoring, lack of oil changes or bad manufacturing causes this. Some very high mileage cars and bikes that have spent their lives on motorways and serviced regularly are found to be almost as new when stripped down. Worn engines may be a problem, high mileage may well not be. Any performance modification to an engine that is worn out or poorly tuned will have detrimental effects. However, an engine in good condition, with good ring and head gasket sealing, should be able to use nitrous without any abnormal wear.  Therefore if the engine is in good condition without any leaks and the proper equipment then the high miles won’t matter.  I run nitrous on my car that is a little bit over 150k miles!

What setup should I use?  Dry, Wet, Direct port????
There are three major styles of kits: The plate system, the dry manifold system, and the direct port system. Each style has its advantages and disadvantages.

Plate System
Plate systems are the cheapest, easiest to install, and are the least accurate in Nitrous metering to the cylinders. The 'plate' fits under the carb or between the TB and intake in FI cars. It introduces the Nitrous/Fuel mixture all at that point, but distribution to the cylinders is not equal. The carb cars are better suited, as all intake runners are directly under the carb. Those with TPI or LT1 cars have large differences in how much fuel and nitrous each cylinder gets, as some runners are a foot further back than others. Kits range from 50 to 300 hp.

Dry Manifold System
Most 'dry manifold' kits are aimed toward FI cars-TPI and LT1 especially. Instead of the fuel and Nitrous both being introduced in the same point as the plate system, the fuel is injected using the fuel injectors the motor uses-the Nitrous is still injected in the same manner as the plate systems. This style offers several advantages over the plate system: it is easier to install, fuel is more evenly distributed to each cylinder, and it is less messy to install-no fuel teeing. It also has several distinct disadvantages: it is more expensive, it attempts to combine engine and Nitrous fuel requirements into one system, it uses a pre-set computer chip to meter fuel under Nitrous-if the chip is out of adjustment with the requirements of the Nitrous may cause heavy engine damage. It does not work well with carb motors because of design. Kits run from 100 to 175 hp.

Direct Port System
Direct port systems are the most accurate in fuel and Nitrous metering, are the most expensive, require heavy fabrication/modification, and are not easily hidden. Direct port systems put both a fuel and Nitrous line to each intake runner on an engine. Since each runner is individually tunable, equality can easily exist between cylinders. To do this, each cylinder needs both a Nitrous and Fuel line run it-8 fuel and 8 Nitrous-all bent and installed precisely. It is obvious you should either take the intake off the car first, or better yet, have a pro do it. The kits also are expensive, starting at $700, not including pro installation. These kits are the safest and most powerful when using Nitrous Oxide. Kits add from 200 to 500+ extra hp.

How do I build a nitrous motor?
Guys who use Nitrous or build Nitrous motors professionally have a motto:
Build a nitrous motor as strong as one that would make the same power on the motor only.
This is how to build a motor for Nitrous that will outperform and outlive motors not built only for Nitrous use. It is expensive, as you need parts that are stronger than anything the factory ever put out. You will need pistons, rods, crankshaft, and block for the bottom end.

Bottom End
Nitrous motors need to be built for strength, not high rpms. Lightweight,” loose" motors will not last under Nitrous-you need strong, tight engines in order for you to thrive. First, take the motor apart, clean it and have it machined by a machine shop that specializes in race engines, rebuilding places don't cut the mustard. Second, since you will be spending almost all of your money on a crank, rods, and pistons, you should get a 400 to replace that 305 or 350. Third, get only premium parts-pink rods, TRW pistons and GM steel cranks are NOT premium parts. Get 4340 rods-as long as possible-usually 6". Get a stroker crank made out of premium steel-since the extra cubes only cost a little bit more. Get good pistons-J&E, Wiseco, Manley...etc matched to rod length and crank stroke. Have it balanced and thrown in with the proper parts. Also it is a good idea to have a splayed four bolt main, since the two bolt caps can be weak-stud it also.

Top End
The top end is where the power is, bottom end work is only to increase strength, durability, and cubic inch displacement. You need to have the proper intake, heads, and cam in order to make big power. It is best to closely match the cam and heads first, as there are less choices-and possible mistakes, in intake manifolds.

Cams for Nitrous motors will not make peak power at different rpms than motor only cams, but special considerations must be made. The cam controls valve motion, key to power or lack of it. Since Nitrous goes in as a compact liquid and escapes as a pressurized gas, steps must be taken in cam selection in order not to create backpressure that will cut power. If your heads flow better than 80% intake to exhaust, you can use a single pattern cam. If your heads flow under 80%, the backpressure of a single pattern cam is too much, a dual pattern is needed. A single pattern cam has the same duration and valve lift on both intake and exhaust. Dual pattern cams have more exhaust duration and valve lift than intake, allowing more exhaust gas out. The selection should also consider that heads that flow good at higher lifts should use that advantage, roller cams allow a lot more leway in lift vs duration.

Heads must be matched to the cam closely, a head meant for 7500rpm use will be useless on a 5500rpm motor, it will actually hurt power. For advice on how to pick heads for power, look at the sections on motor work and cam selection at this web site. Heads make more power if the ratio of intake to exhaust flow is 80% or greater, otherwise the cam must be a dual pattern to make the max power.

Intakes are also important. If you have a carb motor, you can either get a dual plane or single plane manifold. Each has its own strengths and weaknesses. Dual plane intakes are meant to pump up bottom end torque offsetting the loss of hp high up. You can buy dual plane intakes for high or low rpm duty, still keeping low rpm torque. Those individuals with engines 350 ci and smaller should use a dual plane in order ro pump up torque. Single plane intakes are meant to pump up high rpm hp without considering the loss of low end torque. If you have a large-383 ci or bigger engine that has too much torque to hook up, a single plane is for you, as it will kill some torque and give you more hp on the top end. Nitrous is not picky with type of intake, but the motor is-do the right thing. TPI cars have fewer choices and therefore fewer opportunities to pick the wrong intake. If you have a low revving, or small size motor, a stock or ported stock style TPI intake will work best. If you have a higher revving, or larger ci motor that needs all the torque it can get, buy an Accel Superram intake. The Superram will increase high rpm breathing without hurting low end torque. If you have a very high revving, or a motor with too much low end torque, get a TPIS miniram. The Miniram is the same principle as the single plane intake, and GM's LT1 intake is a clone of this.
Where do I mount my bottle?
Nitrous bottles usually come with siphon tubes and, in order to maintain proper nitrous pickup, it is important to mount the bottle correctly. It is recommended to mount the bottle at a 15 degree angle with the valve end higher than the bottom of the bottle. The valve end of the bottle should point to the front of the vehicle and the valve knob and label should face straight up.

Do I need to do anything with my fuel system?
Nitrous kits demand fuel pressure under load (engine load). Most cars with carbs have a block mounted, or mechanical fuel pumps, and FI cars usually have an electric pump in the fuel tank. The FI guys are fine; unless the pump is weak then you must replace it. The guys with carbs will have to buy an electric pump, because even a performance mechanical pump can't pump enough fuel at low engine rpms. You have to mount it as close to the fuel tank as possible, while still being inline with the fuel lines of the car. Mallory, Carter and Holley make excellent pumps for street use.

In order to get fuel to the Nitrous kit, you must T your line in order to get fuel. FI guys use the Schrader valve on TPIs or LT1s. The carb guys must use a T cut into the fuel line, which are included in most kits. You then set pressure to the kit at the psi called for in the manual under load; you may or may not need a fuel pressure regulator to do this.

If your motor makes a lot of hp-over 400 by itself, or if you run a lot of nitrous-200 hp or more, it is smart to run two separate fuel pumps. One should be for the motor and one for the nitrous kit. You may even have to run two 1/2" fuel lines depending on how much hp your motor and kit can produce. If you run into this situation, expect to spend a lot of time and money in order to get enough fuel into your engine.

What is all this talk of timing?
Behind fuel, timing is the most important area of Nitrous use to understand and follow. To get maximum power from a naturally aspirated or forced induction motor, you run the timing as high as detonation allows-you get max power there. By using better gas, you can put in more timing and get more power. Nitrous doesn't work that way. You must retard the timing when using Nitrous. Why? Because it pumps up cylinder pressure so much that detonation may occur, resulting in broken pistons and bent rods. You definitely don't want to do that! How to set timing: For every 50 hp in Nitrous you add to a motor, you must retard timing by 1-1/2 to 2 degrees in order not to damage parts. For a 150 hp kit, you would take 4-1/2 to 6 degrees of timing out. Since taking timing out when the car is not using Nitrous hurts power, you can either move the timing manually every time, or buy an ignition system that is controllable from inside the car when you want to.

What does Nitrous work best with?
Nitrous needs a few things in order to work to its full potential. First, you need a free flow exhaust system-headers,3" cat (f-bodies),and a good 3" cat back exhaust. Second, you need good tires, because Nitrous pumps up torque so much you may burn the tires for blocks.

Some parts that hold back normal motors may actually help nitrous motors go faster. For example, if you have 2.73 gears in your car, it is most probably slower than having 3.73 gears. With nitrous, you will not burn as much rubber with the 2.73s,and may even be able to activate the system sooner in your run-making better ETs with lower mph. Torque converters with high stall speeds on street tires with nitrous are a guarantee that you will either burn rubber, or not be able to activate the system as early.

You will need to have a new high performance clutch put in manual cars, autos need a trans prepped for race conditions because the extra torque will kill clutches and other parts very quickly. You should also have a limited slip rear, because the power will certainly overpower a 'one-legger'.

Nitrous also works best with motors that are stock or mildly modified. Those with more modified motors will not see as great an increase in power as non-modified ones. Nitrous works the same in different size motors, depending on kit size.

What is the purpose of purging?
Nitrous systems are calibrated to be used with liquid nitrous when you connect the line to your cylinder and open your valve. The air that was in that line is now compressed forward towards your nitrous solenoid. Purging allows this compressed air to escape and pulls the liquid forward to your solenoid, allowing a correct mixture of nitrous and fuel at the initial activation of the system. The purge is also used to relieve pressure from the system after use when the valve is closed. Nitrous oxide expands with a rise in temperature. When you turn on your nitrous bottle and purge your line, you fill that line with liquid nitrous as long as your bottle is open. As temperature in that line increases due to under-hood heat, the pressure increase may use the bottle as a reservoir. But once you purge that line, if you close your bottle the nitrous in the line has no where to bleed off expansion and will rupture if not purged out.  This is a rare case, but if you see a line rupture it is usually when the bottle is closed after the line has been purged.  If you make run and come back and turn the bottle off without purging the line, the expanding nitrous will also put an extra strain on your solenoids and plungers, cutting down their life expectancy dramatically.

Should I add that extra pound when I get filled?
People are always taking their bottles to the local speed shop and asking "hey - can you squeak me in an extra pound or two, buddy?"  That is definitely not what you want if you're looking for optimal performance. If you need more nitrous capacity, buy a larger cylinder but do not overfill your bottles.  If you had a clear ten pound nitrous bottle and filled it with ten pounds of nitrous, you would see that two thirds of the cylinder was full of liquid and the top third was a layer of gas.  That layer of gas is called a pressure head.  That is what gives you your pressure stability. If you overfill your bottle, you decrease the size of that pressure head and when you begin to siphon nitrous from your cylinder the liquid can not boil off fast enough to maintain a decent pressure curve. In this case, more is not always better.

How much does the air matter?
Of all engine combinations, a nitrous engine is the least affected by air quality changes. The reason for this is because a nitrous racer carries his own atmosphere with him in his nitrous bottles.  The outside atmosphere is only responsible for one half of his engine's horsepower.  We are not saying that air conditions do not have an effect on a nitrous car but rather that they are just not as drastic as in a non-nitrous naturally aspirated or supercharged engine where the outside atmosphere is responsible for 100 % of the horsepower.  Since a nitrous engine is still naturally aspirated in the sense that it has to draw outside air in, the barometric pressure is responsible for how much nitrous a given engine will swallow before it spits it out in a form of reversion. There is also the side that without any water in the air in the form of humidity your nitrous combination will be more prone to detonation.

What are some common things people should think about?
Don't be afraid of Nitrous. Properly used, it is great. Abuse it and you will be walking home with a blown motor. Learn all that you can before getting a kit, some people should use something other than Nitrous to attain their goals.
Read the manual carefully when you buy a kit.
Fuel is the most important commodity in your engine, make sure you have enough.
Make sure your ignition system is strong.
Make sure you set the timing to the recommended settings as stated by the Nitrous kit manufacturer.
Find a place local to you that offer Nitrous refills for a fair price.
Get the proper permits in order to use Nitrous Oxide in your car.
Since Nitrous will make your car go faster in the quarter mile, you must gear the car for Nitrous use, not for the motor only.
Enjoy yourself.