Installing a Nitrous Oxide System (NOS)

Installing a NOS kit is a simple process of installing the nitrous tank; a few injectors (which are also called nozzles); and a few solenoids; routing a few meters of tubing (or piping) from the nitrous tank and a fuel line to the solenoids, and the solenoids to the injectors; and then fitting a few switches to arm the electrical circuit that energizes the solenoids. If you are installing a Dry System, you don't need to run a pipe from your fuel line to the fuel solenoid as you don't need to install a fuel solenoid but you will need to modify your EFI system to provide the correct amount of fuel when you engage your NOS system. In my experience, the best way to install the nitrous system is to install the nitrous tank first, followed by the injectors and the solenoids, then connect your feed lines, and connect your solenoids to the battery. This will ensure that each of its elements correctly placed to operate at their full potential. If you are installing a Wet System, you must test the system and ensure that the fuel pressure to your fuel solenoid is constant and adequate. This may require that you install a high pressure fuel pump and/or a fuel regulator.

Begin by installing the NOS tank. The correct installation of the tank is important to getting the most out of your nitrous system. As we've mentioned in our basic nitrous system guide, the NOS tank has a siphon tube that extends from the release valve to the bottom of the tank. The siphon tube reaches the side of the tank on the opposite side of the label. Therefore the tank should be installed at a 15� angle, with the label facing up and the release valve facing the front of the vehicle. This will ensure that more of the liquid N₂O is used before the siphon tube begins to pick up gaseous Nitrous Oxide, even under acceleration.

Another consideration is the pressure of the NOS tank. The pressure of the NOS tank will fluctuate as the ambient temperature fluctuates. This can cause problems with the correct calibration of your air/fuel mixture. To overcome this problem, you should ensure that the NOS tank is mounted away from heat sources (such as the exhaust system) and out of direct sunlight. You can also use a NOS blanket to insulate the tank.

You should install the injectors next. The placement of the injectors will depend on whether you're installing a system with a single injector, or a Direct Port System that requires one injector per cylinder. When you need just one injector, you should install the injector as close to the throttle body as possible. If you have a rubber inlet hose connected to your throttle body, you must drill a suitably sized hole to fit the injector, and bolt the injector down with a nut and washer on either side of the hose. If you have a cast aluminum manifold, you must drill a hole and tap a thread into the cast aluminum for the injector to screw into. If you are fitting a Direct Port System, make sure that everything that must be fitted to the intake manifold is in place and find enough space on the manifold to fit the injectors. The injectors must be fitted at the same distance from the cylinder head but try not to fit the injectors too close to the cylinder head. Also, wherever you fit the injectors, apply a little locktight to the thread to ensure that the injector does not work itself loose. If you are installing a Direct Port System, you would need to install a distribution block between the solenoids and the injectors. The purpose of the distribution block is to distribute the fuel and nitrous between the injectors. Although it is not crucial, try to install the distribution block so that the tubes are more or less horizontal. The injectors for a Wet System has two inlets � one for fuel and the other for nitrous. You must connect the right tube to each inlet as indicated on the injector.

The next step is to install the solenoids. These should be installed away from the exhaust manifold but as close to the nitrous injectors as possible. The solenoids must also be installed slightly higher than the injectors to ensure that the nitrous and fuel do not need to flow upward as this will reduce the effectiveness of the system. The solenoids are electrically operated; therefore you'll need to run a few electrical cables to the solenoids.

Once you have your hardware in place, you can install the nitrous and fuel supply lines. It is best to route the tubing that carries the nitrous to the engine bay along the stock fuel line as this would be routed securely, and away from heat sources. The tubing should be secured to the vehicle so that it cannot be damaged by abrasion or by moving suspension and drive train parts. You can use nylon tie-wraps to secure the tubing to the vehicle but � inch Tinnerman clamps work much better. The tie-wraps or clamps should be placed no further than 18 inches apart. Whenever you route the tube trough a metal body panel, be user to use suitably sized rubber grommets to prevent the body work from cutting through the tube.

If you are using nylon tubing, you can use a sharp utility knife to cut the tube to the correct length leaving about 2 inches of free play at either end for possible flexing. Never cut the tubing too short and never cut the tube using a scissors or wire snips as this will deform the tube and make fitting the olive and nut quite difficult. Once you have cut the tube to the correct length, slide the nut over the tube with the treaded part facing the end of the tube. Never tighten the nut too much as this will cause the olive to compress the tube and will restrict flow through the tube. Then slide the olive over the tube. Secure the nut to the outlet on the NOS tank while keeping the tube in place and repeat the process at the other end where you must secure the nut to the inlet on the nitrous solenoid. The tube from the solenoid to the injector will require the same treatment. You can install the tube from the fuel solenoid to the injector as well but don't secure the tubing to the fittings on injector just yet � you will need to perform a few tests first. Also beware, the injector for a Wet System has two inlets � one for fuel and the other for nitrous. You must connect the right tube to each inlet as indicated on the injector. Next, tap into your fuel line using a metal T or Y splitter and fit the tubing that will supply fuel to the fuel solenoid and connect it to the inlet on the fuel solenoid.

The final step is to install the electrical circuit that will power the solenoids. The NOS solenoid must lift the plunger against the pressure that can be upwards of 800 psi in the system. A fair amount of current (amps) is required to accomplish this task so make sure that the electrical cables can supply the required amperage to lift the plunger. The electrical circuit should supply both solenoids with power and should incorporate a fuse, a microswitch fitted to the accelerator linkage, an arming switch and a relay. Start by disconnecting the negative terminal from the battery. This will prevent you from causing short circuits while working on the electrical system. Run a live wire from the positive terminal of the battery to the fuse box under the dashboard and on to a relay. Another live wire can then be run from the relay to the relay to the solenoids. This wire must carry sufficient current to activate both solenoids. You can fit the arming switch on the live wire between the relay and the solenoids as this wire will run close to the dashboard area; however it is better to place the switches on the earth wire. The earth wire will run from the solenoids to a suitable metal point on the vehicle's body but it is best to run the earth wire to the negative terminal on the battery. You can fit the microswitch to the earth wire as the solenoids would be placed close to the accelerator linkage.

There you have it, you're done. All that's left now is to test the nitrous system and ensure that the pressure to your fuel solenoid adequate, and then tune the nitrous system for best performance.

Testing and Tuning Nitrous Injection Systems

by "Bad Ass" Bre (February 03, 2007)

TESTING NOS SYSTEMS

Once you have your nitrous system installed, you must test the system to ensure adequate nitrous and fuel flow. This will ensure proper performance and reliability.

Start by ensuring that the fuel line is properly attached to the fuel solenoid and turn the fuel pump on. You can do this by turning the ignition key to the ACC position. Check for fuel leaks where you tapped into the stock fuel line and where the fuel line feeds into the fuel solenoid. Cure any fuel leaks, check again for fuel leaks and then disconnect the fuel line from the nitrous injector. Activate the system and check for fuel flow when the system is activated, and that the fuel stops flowing when you deactivate the system. If you don't get fuel flow, check that the fuel solenoid is operating properly � you should hear an audible click when the solenoid is activated; check that you have fuel flow at the fuel filter; and ensure that fuel line is not kinked, twisted or bent. If you do have fuel flow, turn the vehicle's ignition off and properly secure the fuel line to the nitrous injector.

Now open the release valve on the nitrous tank check for frost along the nitrous feed line. The frost will indicate a nitrous leak. If you find any leaks, close the release valve on the nitrous tank and cure the leaks. Open the release valve again and ensure that you've cured all nitrous leaks. Then disconnect the nitrous line from the nitrous injector. Activate the system and check for liquid nitrous flow when the system is activated, and that the nitrous stops flowing when you deactivate the system. If you don't get nitrous flow, check that the nitrous solenoid is operating properly; and ensure that nitrous line is not kinked, twisted or bent. If you do have nitrous flow, you can properly secure the nitrous line to the nitrous injector.

TUNING NOS SYSTEMS

Nitrous tuning is another simple procedure but you should first tune your engine without nitrous as you will be running without nitrous for most of the time. Tuning the nitrous system is quite straight forward � you start with the jet sizes recommended by the manufacturer of your nitrous system and gradually adjust the jet sizes until the air/fuel mixture added by the nitrous system is perfect.

So install the jet sizes recommended by the manufacturer of your nitrous system. This will be conservative and will err on the rich size (i.e., too much fuel), which is the safe side to err on. Run you engine for a while with the nitrous activated and then check each of your spark plugs to determine how the air/fuel mixture is burning. The correct air/fuel mixture will produce a brownish, grayish-tan color on the spark plugs. If the spark plugs have a sooty, black color, your air/fuel mixture is too rich and you should increase the nitrous jet to the next jet size. If the metal part of the spark plugs displays a bluish or rainbow coloration, go to a smaller nitrous jet size immediately. Repeat this test until your spark plugs display the correct color. Never jump up by more than one jet size on the nitrous side and never try to work your way down from a lean mixture � that's just looking for trouble and major engine damage. You can make more power by increasing the fuel jet size and then adjusting the nitrous jet size up until your spark plugs display the correct color again.

WARNING: Back off as soon as you get detonation and reduce the size of your nitrous jet!

You may also need to adjust your ignition timing as nitrous oxide makes the air/fuel mixture burn much faster than normal. Retard the ignition timing by 2� increments (i.e., less advance before TDC) until you feel a noticeable loss of power. Then advance the ignition timing by 2�.

Now that that's done, your nitrous system is installed, tested and tuned; all that's left is for you to enjoy responsibly � always enjoy power responsibly!

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NOS Basics and Layout

The basic nitrous oxide injection system, or a NOS kit, is pretty straight forward and easy to grasp. It consists of a nitrous oxide tank, some tubing, a nitrous solenoid, a fuel solenoid and toggle switch, throttle position microswitch, jets, a nitrous fogger, a relay, nylon pipe, and a distribution block.

The nitrous tank is used to store Nitrous Oxide in a liquid form. The tank is actually a pressurized canister as Nitrous Oxide must be compressed to remain liquid at room temperature. Remember N₂O reaches boiling point (i.e., it becomes gaseous) at -127� F and more Nitrous Oxide can be stored when it is in a liquid form. Approximately 850 psi of pressure is required to keep Nitrous Oxide liquid at room temperature and at sea level but the nitrous tank must be pressure tested and certified to withstand 1,800 psi. If the certification on your NOS tank is older than five years, your nitrous dealer will not refill it and you will have to have the tank pressure tested and recertified. The tank is mounted in the car's trunk and has a siphon tube that is connected to the release valve and extends to the bottom of the tank. The tank must be mounted at a 15� angle to ensure that the maximum amount of Nitrous Oxide can be released from the tank.

High pressure nylon or Teflon inner-lined braided-steel pipe is used to carry the Nitrous Oxide to the engine where it is regulated by the NOS solenoid. The solenoid is an electrically controlled valve which uses a strong electromagnetic field to open a small plunger the blocks the flow of the liquid Nitrous Oxide. A second solenoid is used to supply extra fuel so that the air/fuel mixture remains constant. Both solenoids are controlled by electric switches that activate the electromagnetic field. The NOS system should have at least two switches � a microswitch that is fitted to the accelerator linkage and is only activated at full throttle; and a spring-loaded momentary switch that is activated by the driver. The microswitch on the accelerator linkage ensures that the nitrous system can only be activated at full throttle. Activating the system during part throttle or during a gear change can have very catastrophic consequences. As an added precaution, the oil pressure switch can also be used to ensure that the system can only be activated when the engine is running and there is oil pressure. Starting an engine with NOS in the combustion chamber can also be very catastrophic.

Some more high pressure nylon or Teflon inner-lined braided-steel pipe is used carry the nitrous and fuel (which are still separate at this stage) to the intake manifold where it is released into the engine via two small jets that are located in a special nitrous injector. The jets must be correctly calibrated to release the correct amount of fuel for a given amount of nitrous. In addition, the pressure on the fuel supply side must be adequate and at a constant level to ensure that the air/fuel mixture is correct at all times. This may require the fitting of an electric fuel pump and a fuel regulator.

The quantity of the nitrous flow depends on the size of the jet fitted. A jet is basically a screw with a whole through it. It's used as a restriction tool depending on the size of the link up orifice. Applying a bigger jet is the easiest way to squeeze a bit more power out of your current system. The fuel supply comes from a similar jetting system.

There you have it � the basics behind NOS systems and NOS kits. In our next section we'll look in more detail at NOS installation ...

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An Introduction to Nitrous Oxide (N2O) Injection

Anyone for some NOS?

Nitrous Oxide (N₂O), or NOS as it is commonly referred to, is a quick and easy performance boost for any motor vehicle, regardless of whether it's a car, a bike, a boat or a plane. In technical terms, Nitrous Oxide is a chemical compound that consists of two Nitrogen atoms and one Oxygen atom. However, Nitrous Oxide does not occur naturally as a chemical compound but has to manufactured by applying heat and a catalyst to nitrogen and oxygen compunds. Nitrous Oxide was first discovered by the British chemist, Joseph Priestly, in 1772 but it wasn't until 1942 that Nitors Oxide was first injected inon an internal combustion engine to boost the power output from the engine. Nitrous Oxide is not combustible and is in liquid form when under pressure. When it is released into the combustion chamber the pressure is removed and the Nitrous Oxide becomes gaseous, releasing extra Oxygen that allows your engine to burn more fuel during the combustion process. At the same time, the chemical process of changing from a liquid into a gas absorbs lots of the heat from inside the combustion chamber, reducing the chances of detonation and pre-ignition. NOS thus provides an instant but relatively safe performance boost.

The major advantage of NOS is that it is relatively cheap when compared to all the other forms of car modification and the amount of work involved to install a full nitrous system is far less than that of installing high performance cam shafts, turbochargers or superchargers. The only drawback is that you must refill your Nitrous Oxide tank. Nitrous Oxide is stored in a pressurized tank to keep it in a liquid state. Unfortunately, Nitrous Oxide refills are not as freely unavailable as gasoline and must be purchased from an authorized dealer. The relative low cost of installing a NOS system makes it an ideal power boost project for anyone who can read and understand a little simple physics. As with anything in life, if you don't do it right, you're going to get problems. There is also more to installing NOS than just bolting a NOS tank to your trunk and connecting a long tube to your engine. The bottle has to be mounted at a 15� angle to ensure that the last of the gas is used and none is wasted. The plumbing is also very intricate and can be very tricky to a first time NOS installer.

None the less, in this custom-car.us NOS guide, we will explain the physics of nitrous oxide injection and show you how to install a NOS kit and how to test and tune NOS.

There are three different types of nitrous oxide systems that you can implement:

• The Dry System, which is the NOS system in which no fuel is sent to the intake charge outside the vehicle's normal means.
• The Wet System, which is the NOS system in which fuel and nitrous oxide are supplied through a fogger and then sprayed through the throttle body.
• The Direct Port System, which is a Wet System in which each engine cylinder has its own fogger.

We'll cover all of these over the next few pages. Now let us start with some NOS basics ...

WARNING: NOS causes an extreme increase in fuel combustion; therefore, any problem in your engine can turn out to be 10 times worse with nitrous installed!

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Cylinder Head Porting

Now that we've got a good understanding of air-flow, we can move on to cylinder head porting. If you haven't yet read our article on the basics of cylinder head porting and air-flow, I'd suggest you do so now as it provides the foundation for understanding what we want to achieve with the actual cylinder head porting.

PREPARING THE CYLINDER HEAD

Before we can get started, we need to strip down the cylinder head; remove the camshafts and camshaft pedestals, then remove the valves, valve springs and valve stem seals. You should also remove all manifold studs. With everything stripped, you need to inspect the cylinder head for cracks. It's no good porting a cracked cylinder head, though a cracked cylinder head may still be good for experimenting on, so don't throw it away! The most likely areas where cracks will appear are between adjacent valve seats, and around the valve seats, especially around the exhaust valve seats. You may need to some emery cloth to remove any carbon deposits to do a thorough check.

If you don't see any cracks, have the cylinder head thoroughly cleaned in a chemical bath. You can dip a cast iron cylinder head in a hot caustic solution but don't dip an aluminum cylinder head in it! Caustic solution will react with the aluminum and give off an explosive gas! For an aluminum cylinder head you should use Trichloroethane. If you don't have access to a chemical bath, you can use engine cleaner and a stiff brush to get oil and gasket pieces off. Once the cylinder head is clean and dry, use a sand blaster or a wire brush to clean off any stubborn carbon deposits. Once that's done, do another thorough check for cracks.

If you don't see any cracks, have the valve seats replaced and the valve guides removed by a reputable engineering shop. Replacing the valve seats are not crucial as long as they're in a good condition. However, you must have the valve guides removed.

WARNING: Take care when working with a grinder. Adhere to the following safety precautions when porting cylinder heads and using a grinder in general:

• Wear eye protection when working with a grinder; goggles are advisable but a full face visor would be better.
• Wear a dust mask or a respirator; inhaling metal filings is harmful.

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Toyota

Like the other big Japanese car manufacturers, Toyota has been a popular candidate for car modification and show car projects. At any show car event you wouldn't just expect to see a modified Toyota Supa but also modified Toyota Carolla and Toyota Aristo cars. These days you can even expect to see a custom Toyota Prius Hybrid or two!

Below are some of the coolest Toyota show cars from around the world...

Toyota Aristo

A red Toyota Aristo at the SEMA Show in 2008

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For modified cars and tuning cars

This Web site is not just dedicated to building pimped out cars and custom cars, but to building and tuning fast modified street cars and even faster modified race cars. Custom-car.us will provide you with all the information and articles about modified cars, car customization and car modifications that you will need to build really fast modified cars for street use or for track racing. Our aim is to help you modify your car and its engine to improve engine performance and handling by providing you with all the information, tips and advice you would need to select the correct high performance auto parts for your car, to install them correctly, and to tune them. It doesn't matter whether your car modification project entails building really cool custom cars, fast modified race cars, cool modified street cars, or even pimped out cars we will provide you with the information you would need.
Information about engine tuning and car modification can become quite technical, but we attempt to bring you this information in plain English. We make the information as easy to understand as possible so that even the novice can learn about car tuning and car modifications, as well as how to increase engine power. We also guide you through engine tuning, performance tuning and car modifications for all makes of cars, including BMW, Honda, Ford, Nissan, and much more, with detailed, step by step tuning and modifying tips. And if you do get stuck with a technical term, there's always our glossary of modified car terms that you can checkup the term. If that doesn't help, you can always send us a message through our feedback form.

We discuss various techniques of car customizing and various car modifications, as well as the different car tuning methods you can use to increase engine power, maximize car performance, and build great modified cars; including:

Engine Tuning Learn about the basics behind car modification and engine tuning. Learn how to increase engine power and build engines for power and reliability. Go to Engine Tuning		Cylinder Head Porting Learn all about performance camshafts and cylinder head porting. Also learn about valve timing, camshaft timing and how to degree your camshaft. Go to Cylinder Head Porting
Nitrous Injection Learn how to design wet and dry Nitrous Oxide Systems for your car. Also learn how to install NOS kits to your car and how to test and tune them. Go to Nitrous Injection		Turbochargers Learn how to select and install the right turbocharger kit for your car. Also learn how to minimize turbo-lag and how best to tune a turbo or twin-turbo car. Go to Turbochargers
Superchargers Learn about the different types of superchargers and how to select and install the right type of supercharger that will give you the power you want. Go to Superchargers and Blowers		Electronic Fuel Injection Learn how to maintain, modify and tune electronic fuel injection (EFI), engine control unit (ECU) and engine management systems for the best performance. Go to Engine Management
Ignition Systems Learn about the different ignition systems and how to improve and tune your ignition system for turbocharged, supercharged and modified engines. Go to Ignition Systems		Air Intake Systems Learn how to improve air flow in and out of your engine by eliminating restrictions in the air intake system, and tuning the intake manifold and runners. Go to Air Intake Systems
Exhaust Systems Learn how to design and build performance exhaust systems with the correct primary pipe lengths and diameters for all types of high performance cars. Go to Exhaust Systems		Suspension Tuning Learn more about your car suspension and how to tune your suspension to be able to get the most out of your engine modifications. Go to Suspension Tuning
Pimp Your Ride! Learn about ways in which you can modify and customize your car visually to make it look as hot as it goes in our latest section on pimped out cars. Go to Car Styling		Free Wallpapers Custom-car.us has free modified car and car logo wallpapers for your desktop. We also have great modified race car and modified street car wallpapers. Go to Wallpaper
Join our forum! Join our all new modified and custom car forum where you can discuss your custom car projects, get tips on modifying thecar you have, and much more! Go to our Forum		More Car Pictures Custom-car.us also brings you free car pictures from the top car shows around the world, including the well known Tokyo Auto Salon and the SEMA show. Go to Car Shows

Although it does not have a lot to do with engine power and car performance, we do discuss ways in which you can modify and customize the appearance of your car to make it look as hot as it goes in our section on pimped out cars as it has everything to do with customizing cars, custom cars and modified cars! After all, what is the point of having a hot custom car if it looks a dud, unless you want the sleeper look?
We will be updating this Web site and adding more information on a regular basis so that it can serve as a complete resource on modified cars, custom cars and car modification. We hope that you find this Web site and its car modification guides informative and useful for building your own cool custom car, performance tuning your own car, and getting the best performance out of your car. All the information presented here has been thoroughly researched by our contributors. In our quest to provide the best source of information on car tuning and car modification, human error is always a possibility. Therefore, you should always consult your motor mechanic about your specific car before performing any car modifications to it, and always take the necessary safety precautions before tuning cars and engines! Should you find any errors on our Web site, please inform our webmaster so that we can correct them as soon as possible. You should also note that some car customizations, such as increasing your car's ride height, can adversely affect car performance and safety, while other car modifications may be illegal in your area. You should always ensure that your car customizations are legal

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