I will try to answer a few of the basic nitrous questions we get asked quite often in this section.
First, Nitrous Oxide is a gas which carries an extra oxygen molecule. When extra fuel is added in the presence of nitrous the extra oxygen is stripped off and allows more fuel to be burned, thus increasing cylinder pressure ( much like a turbo, or supercharger ) and therefore making more horsepower, nothing more, nothing less. If these things are done at the right time and , most importantly, in the correct amounts, reliable boosts in power can be had.
All nitrous systems rely on the stripping off of this extra oxygen to mix with extra fuel to make horsepower. They just do this with different methods. The nitrous is always contained in a High pressure tank, usually around 950 psi, but it can get even higher than this. So, this tank needs to be PROPERLY secured in a safe place, also, nitrous oxide IS NOT flammable, some movies have made this an issue, it has even become a problem in some states to have it in your car. So checking with your local laws is in order. Just a personal note, having your nitrous bottle prominently displayed may look cool, but it may not be such a good idea with local law enforcement.
The fuel is supplied in different ways for different systems and will be explained under each companies header.
There are also several safety devices to help keep things from going wrong, I will explain these at the end, as well as how important I think each one may be.
NOS AND NITROUS EXPRESS ( ALSO FAST & FURIOUS)
I will address these two companies together as they are basically two companies building the same product. Both are wet systems, which means they inject nitrous and fuel together. These systems use electrically powered solenoids to supply both fuel and nitrous from seperate locations, they are mixed together at the nozzle by metering jets.Then this mixture is injected into the intake track AFTER the MAF, through a small nozzle. These jets can be changed to select the desired horsepower levels going to the motor. Also, once you get another car, these kits can be removed and tranfered to another car, just by changing the jets to the proper ones.
The fuel is tapped off the fuel line or can sometimes be pulled from the fuel rail test port ( in carbureated applications a seperate fuel pump may be used ), The nitrous is supplied from a high pressure tank, this is then routed through the solenoids that are electrically activated. There is usually a switch to turn on the whole system, as well as some type of activation switch. This can be a wide open throttle switch ( W.O.T.) that activates when the throttle pedal is depressed to the floor, or it can be a push button switch such as on the top of the shifter, there are other types of safety switches which will be discussed later.
These kits reguire that you have decent mechanical ability and some good electrical wiring skills. Be honest with yourself, if you have any doubts as to your ability to install one of these kits, PLEASE pay a professional to do so.
This company uses the throttle position sensor (TPS) to vary pressure at the fuel pressure regulator to raise fuel pressure in the stock injectors to a safe level when injecting nitrous oxide. This is what is considered a dry system as it uses the existing fuel system to meet the needs of the nitrous oxide being injected. This is considered an easier sytem to put together as there aren't as many lines and wires to run and hook-up. This system also keeps an eye on bottle pressure and rpms as part of its system.
Pros and cons of this sytem. It is very easy to install, but several people in the industry are not a fan of " dry" systems as the fuel supply from the stock components can fall short resulting in a lean condition in the motor, which can lead to detonation and eventually breakage of the motor. Personally, I think dry kits are okay for the smallest of horsepower hits, but why not play it safe and install a wet system. I also understand Zex now offers a "wet" system.
I have not seen one of these kits yet, however, they make both wet and dry kits as described above.So in other words they have a kit built like the Zex and they build a kit like the NOS and Nitrous Express. Most parts Edelbrock makes are usually of high quality, so I am sure they build a good kit.
This is the kit alot of people in the industry talk about, but few people buy one. Why? the cost of admission. Retail on the kit is $1,500, yes you can find them cheaper on the web, but they are still very expensive. Mosts kits start in the 400- 500 dollar range, so you can see that the venom is quite pricey.
Now to its function. I was checking a system out at a dealer show. It seems to work on the same principals as the Zex kit above, it is just done in a much fancier more digital way. It is a programable sytem with a very fancy compuer lcd display. Once installed it can moniter bottle pressure and whether the exhaust on the car is rich or lean and correct the nitrous mixture to suit your needs, it is also adjustable in its horsepower levels on the fly. This system is capable of being hooked into your laptop as well, so it really appeals to the techno-wizard crowd. This all sounds good, but it makes for what looks like a very advanced , complicated install for the novice, and it still has the possible pitfalls of any " dry" system.
There are quite a few of these, they are not mandatory, but several are just a good idea. Some of these do not apply to all nitrous sytems.
1.) Fuel pressure safety switch ( about $40 ): This keeps an eye on the fuel pressure going to the solenoid in a " wet" nitrous application. If the fuel pressure for any reason, drops below a certain amount it will shut the system down and save the motor. It mounts inline to the fuel solenoid.
2.) RPM switches ( about $60 ) : These can be hooked up to the tach. On a focus this requires buying a tach signal generator ( an extra $55, oh joy!), Ford Part # 161-M-17361-A200. What this allows for is the nitrous to only activate between a certain RPM.. A " window" if you will. The advantage of this is that you can shut the nitrous off before you hit the rev. limiter in the car ( I have mine set 600 RPM before for safety). The problem with many modern rev limiters is that they drop half of the cylinders electrically to slow the engine. The nitrous is still being fed to these cylinders, " puddling" in the intake track, since it is not being consumed, then when the cylinders come back in it ignites all this " puddled" nitrous and BOOM ( this has cost several mustangs a new plastic manifold, our foci use plastic manifolds as well.) This device can prevent this..Good thing.
3.) WOT switch ( supplied with most kits $ 5): A wide open throttle switch ( usually mounted on the throttle body, often hard to find a good spot for ) will simply insure that the nitrous is only applied at WOT.
A few pics of switch mounts are here: Pics of how to mount the WOT switch
OTHER NICE THINGS TO HAVE
1.) Remote bottle opener ( $240) : Very pricey, but a must if your nitrous is " hidden" from view.
2.) Bottle Heater ($200) : Not a must, but I wouldn't have a nitrous sytem without one. Basically it keeps the bottle heated to a proper pressure ( 950 psi ), so as you can get a proper horsepower hit from your system. You can lose MORE than 50% of your nitrous h.p. hit due to bottle pressure being to low. This device prevents this.
3.) Fuel rail adapter ( $25): Focus Central makes this little part ( can be homemade as well) that allows you to easily tap the fuel supply for a "wet" sytem off of your fuel rail test port instead of splicing into the fuel line, makes life easier.
4.) Purge kit ( $100) : IMO really not needed on the street except for show ; on the track they serve the purpose of getting all the air out of the nitrous lines so the " hit" is instant and full-on
5.) Nitrous pressure gauge ( $40) : Usually come with kits, nice idea to keep an eye on bottle pressure, there is also a remote in cabin one available.
To sum up, you can do a nitrous system on the cheap and it will probably work fine, but it will work better and will be much safer and more reliable if you spend the extra money on some of the good things. As above, some of these kits are QUITE involved , if you doubt your mechanical abilities at all PLEASE pay a professional to do the install for you.
Also, as some of the pros will notice, I have intentionally left out direct port nitrous installs and nitrous controllers, I know about these and have done several, but I feel these are definately in the realm of the professional and do not belong here in a " how-to" area.
Insert standard if you hurt yourself it is your fault statement here, and please, have fun, but be careful and use some common sense