Nitrous Oxide Injection F.A.Q. and as found all over the net....
(From NOS site, originally, I think,  but modified by me)

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How Does Nitrous Oxide 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 572F (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 "buff or dampen" the increased cylinder pressures leading to a controlled combustion process. 


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Why N20? 

Nitrous oxide injection has become a very popular option for today's performance enthusiast for several reasons: 

N20 offers you more performance per dollar spent, than any other performance modification. 
N20 installations are relatively easy to accomplish. 
Since N20 is used only when needed, it offers you the advantages of complete drivability and normal gas mileage while not "on the button." 
Systems available for virtually any power need from 5 HP to over 500 extra HP. 
One of the few performance options available for today's computer controlled, fuel injected engines. 
Systems can easily be removed or transferred to another vehicle. 

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Q: Will N20 affect engine reliability? 

Theoretically not.

But probably...One day its inevitable no engine goes forever so just accept it!

And It may well be nothing to do with the nitrous! It always gets the blame though!

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Q: Can I simply bolt a N20 kit onto my stock engine? 




 

 

A: Yes, There are N20 systems for virtually any stock engine application. The key is to choose the correct kit for a given application; i.e., 4 cyl. engines normally allow an extra 40-60 HP, 6 cyl. engines usually work great between 75-100 extra HP, small block V8's (302/350/400cid) can typically accept up to 140 extra HP, and big block V8's (427/454) might accept from 125-200 extra HP. These suggested ranges provide maximum reliability from most stock engines using cast pistons and cast crank with few or no engine modifications. 


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Q: What are some of the general rules for even higher H.P. gains? 

A: Generally, forged aluminum pistons are one of the best modifications you can make. Retard ignition timing by 4-8 degrees.  In many cases a higher flowing fuel pump may be necessary. Higher octane (100+) racing type fuel may be required as well as spark plugs 1 to 2 heat ranges colder than normal with gaps closed to .025"-.030". 

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Q: How much performance improvement can I expect with a nitrous system? 

Loads..... Depends on jetting. You simply choose!


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Q: How long will the bottle last? 

Approximately 10bhp per lb per min.

So a 2.25 lb bottle on a bike will give just less than a minute with a 25bhp increase. 


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Q: How long can I hold the nitrous button down? 

A: It is possible to hold the button down until the bottle is empty. However you will be lucky to find enough road.......


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Q: When is the best time to use nitrous? 

A: At wide open throttle only.  Due to the tremendous amount of increased torque, you will generally find best results, traction permitting, at early activation.


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Q: Will I have to rejet my carburetor on my car when adding nitrous? 

A: No! The N20 system is independent of your carburetor and injects its own mixture of fuel and nitrous. 


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Q: Is nitrous oxide flammable? 

A: No. Nitrous oxide by itself is non-flammable. However, the oxygen present in nitrous oxide causes combustion of fuel to take place more rapidly. 


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Q: Will nitrous oxide cause detonation? 

A: Not directly. Detonation is the result of too little fuel present during combustion (lean) or too low of an octane of fuel. Too much ignition advance also causes detonation. 

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Q: Where can I get my bottle refilled? 

A: There are many performance shops that can refill your nitrous bottle generally for around $20. All Nitrous Oxide certified distributors can refill your bottle. Or in the UK Kingston Medical Gases will rent you a big bottle to fill your smaller ones from, and collect and deliver refilled ones too! Many welding and engineering shops can supply too.


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Q: Is there any performance increase in using medical grade nitrous oxide? 

A: None! All the same.


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Q: Is it a good idea to use an aftermarket computer chip in conjunction with a Nitrous System? 

A: Only if the chip had been designed specifically for use with nitrous oxide. Most aftermarket chips use more aggressive timing advance curves to create more power. This can lead to potential detonation. You may wish to check with the manufacturer of the chip before using it. The top manufacturers, such as APE & SuperChips do make special chips for use with nitrous. 



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Q: Does nitrous oxide raise cylinder pressures and temperatures? 

A: Yes. Due to the ability to burn more fuel, this is exactly why nitrous makes so much power. 

But the richer you run it the less heat. So if you want more power use more of both. Do not just try to weaken the mixture to the limit as richer is safer!

You want pressure, its what makes the car/bike faster, but you don't want the heat. Go Richer and more retarded the more you add!


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Q: Are there any benefits to chilling the nitrous bottle? 

A: No. Chilling the bottle lowers the pressure dramatically and will also lower the flow rate of the nitrous causing a fuel rich condition and reducing power. On cold evenings you might run on the rich side. For optimal running conditions, keep bottle pressure at approximately 800-900 psi. 


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Q: Are there benefits to using nitrous with turbo or supercharger applications? 

A: Absolutely! In turbo applications, turbo lag is 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. 


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Q: What effect does nitrous have on an engine with considerable miles on it? 

R.I.P............  Unless it is pretty healthy.


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Q: Will the use of nitrous oxide affect the catalytic converter? 

A: No. The increase in oxygen present in the exhaust may actually increase the efficiency of the converter. Since the use of nitrous is normally limited to 10-20 seconds of continuous use, there usually are no appreciable effects. Temperatures are typically well within acceptable standards. 



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Q: Can high compression engines utilize nitrous oxide? 

A: Absolutely. High or low compression ratios can work quite suitably with nitrous oxide provided the proper balance of nitrous and fuel enrichment is maintained. NOS kits are used in applications from relatively low compression stock type motors to Pro-Modifieds, which often exceed 15 to 1. Generally, the higher the compression ratio, the more ignition retard, as well as higher octane fuel, is required. For more specific information talk to a qualified technicians. 



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Q: What type of cam is best suited for use with nitrous oxide? 

A: Generally, cams that have more exhaust overlap and duration. However, it is best to choose a cam tailored to normal use (when nitrous is not activated) since 99% of most vehicle operation is not at full throttle. There are special cam grinds available for nitrous competition which have more aggressive exhaust profiles etc. Since cam selection depends largely on vehicle weight, gearing, etc., it is best to stick to cam manufacturer's recommendations for your particular goal. 


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Q: What type of nitrous system is better; a plate injection system or a direct port injection system?  (Car)

A: The advantages of a plate system are ease of installation and removal, ability to transfer easily to another vehicle, ability to change jetting combinations quickly, and, in most cases, provide you with all the extra HP you will ever need (75 to 350 more HP). In some cases, such as in-line type engines with long runners, a direct port type system is advisable for maximizing distribution. 


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Q: Should I modify my fuel system to use nitrous oxide? 

A: Most stock fuel pumps will work adequately for smaller nitrous applications. It is important to check to see if your pump can flow enough fuel to your existing fuel system (whether carburetor or fuel injected), as well as being able to supply the additional fuel required by the nitrous kit under full throttle conditions. It may be a good idea to dedicate a separate fuel pump to the nitrous kit. 





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Q: What are the advantages of using nitrous compared to other performance options? 

A: The cost of many other performance options can put you in the poorhouse. Dollar for dollar, you can't buy more performance with less money than nitrous. With a nitrous system, performance and reliability can be had for a much more reasonable price while retaining the advantages of a stock engine during normal driving. And, nitrous offers tremendous gains in torque without having to rev the engine to excessive rpm's. These factors help your engine last longer than many other methods of boosting horsepower. 


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Q: How do I know how much nitrous is left in the bottle? 

A: The most reliable way is to weigh the bottle to determine how many pounds remain. When a bottle is near empty (about 20% or less nitrous remaining) a surging effect is normally felt. 


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Q: What is the function of the blow-off safety valve on the bottle? 

A: It is very important not to overfill a bottle; i.e., a 10 lb. capacity bottle should not be filled with more than 10 lb. of nitrous oxide by weight. Over-filling and/or too much heat can cause excessive bottle pressures forcing the safety seal to blow and releasing all the contents out of the bottle. 


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Q: Will I have to change my ignition system? 

A: Most late model ignition systems are well suited for nitrous applications. In some higher HP cases, it may be advisable to look into a high quality high output ignition system.

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