Technical Information from NOS
Nitrous System Theory, Selection,
As modern engines become more difficult to modify, the
use of nitrous oxide to obtain phenomenal performance
gains is on the rise and for good reason. We firmly
believe that our nitrous systems and related products
are the highest quality, performance and value available
anywhere in the world. We can make this claim because
we’ve been manufacturing nitrous systems and components
since 1978. The value of this to you is the vast experience
we have accumulated throughout the history of our company.
Among the many true bolt-on perform-once enhancing products
available, there are few that can even came close to
comparing to the dramatic results of a power increase
provided by one of our nitrous systems. In both the
simplicity and reliability that you get when you install
a nitrous system that carries our world-famous NOS logo,
you’ll be amazed at how easy it is to produce
the one thing everyone is always searching for more
When you consider all of the options you have to get
an engine to release all of the potential power it can,
there is no equal to the ability nitrous oxide provides
you. If you look at a nitrous oxide system an a dollar
per horsepower basis, you’ll find that a nitrous
system from NOS can provide the greatest value for each
dollar of your precious investments. Our experience
throughout the years has proven to us that performance
enthusiasts and racers alike are most impressed by the
ability to add 10 to 200 horsepower within a period
of just a few hours. By carefully choosing the correct
system for your applications, you’ll be assured
of a performance increase and reliability factor that
could only be compared to doubling the size of your
engine by simply activating your NOS nitrous system!
How to Make Horsepower
An engine operates by burning fuel, which then expands
and pushes the pistons down. Want to make more horsepower?
Burn more fuel so it will push the pistons down with
mare force. Sounds pretty simple. But, it’s not
quite so easy. While there are any number of factors
that make increasing power a complex engineering problem,
we will deal with three of the mast basic ones here.
First, all fuels require oxygen in order to burn. If
you want to burn more fuel, you need to also put in
more oxygen. Virtually all engine performance products
increase power by increasing the flow of fuel and oxygen.
Camshafts, larger carburetors or valves, porting, intake
manifolds, exhaust headers, superchargers, turbochargers
and nitrous oxide are clear examples of how improved
engine breathing (putting in more oxygen in order to
burn mare fuel) will give you an increase in horsepower.
Nitrous oxide injection systems are probably the most
efficient way to increase the flow of oxygen and fuel.
That’s the basic reason why nitrous systems produce
such large horsepower increases.
Another basic power factor is vaporization of the fuel.
Gasoline, as with other racing fuels, will not burn
in a liquid state. The gasoline must be turned into
a vapor for it to burn. This process of turning gasoline
into a vapor is simple evaporation. It is basically
no different from setting a glass of water outside and
waiting far it to dry up. In the engine, of course,
evaporation happens very quickly. Engine heat and fuel
atomization are the keys to accelerating the evaporation
process enough to turn raw gasoline into a vapor at
8000 RPM. The process of atomization turns raw fuel
flow into tiny droplets which then evaporate faster
due to the larger amount of surface area presented for
evaporation. The size of the fuel droplets is very important.
Take a large droplet of gasoline, break it up into 10
smaller droplets, and you’ve increased the surface
area far more efficient evaporation. The result is more
fuel available to be burned and do work during combustion.
A well-designed nitrous system will produce very small
droplet sizes in the supplemental fuel that flows into
the engine with nitrous. This is one of the reasons
that NOS nitrous systems can make more horsepower than
some other systems.
The third basic power factor we will look at is air/fuel
mixture density. Ever try to jog on top of a 10,000
foot pass in the Rockies? Leaves you gasping for breath
doesn’t it? That’s because the air is thinner,
less dense, higher up in the atmosphere than it is at
sea level. It is also why you would run slower on a
track in Denver than you would near sea level in New
Jersey. Density is affected by atmospheric pressure
(the weight of the atmosphere above you), heat and humidity.
We can’t change the pressure of the atmosphere,
but we can regulate the heat of our intake charge to
some extent. Cool cans and intercoolers make extra power
by cooling the fuel and air/fuel mixture to make it
denser. And the denser the mixture is, the more the
cylinder is packed with fuel and air to burn and make
power. When nitrous oxide is injected it turns from
a liquid to a gas instantly and becomes very cold. This
cold nitrous vapor drops the temperature of the whole
intake charge in the manifold by as much as 65 degrees
F. The denser mixture that results helps an engine produce
even more extra horsepower with a nitrous system.
What Nitrous Oxide Is and What Nitrous Oxide
To your engine, nitrous oxide is a more convenient form
at normal air. Since we are only interested in the oxygen
the air contains, nitrous oxide provides a simple tool
for manipulating how much oxygen will be present when
you add additional fuel in an attempt to release more
power. The power always comes from the fuel source.
Nitrous oxide is not a fuel. Nitrous oxide is a convenient
way to add the additional oxygen required to burn more
fuel. If you add only nitrous oxide and do not add additional
fuel, you would just speed up the rate at which your
engine is burning the fuel that it normally uses.
This, more often than not, leads to destructive detonation.
The energy comes from the fuel, not the nitrous. Nitrous
oxide simply allows you to burn a greater quantity of
fuel in the same time period; thus the overall effect
is a tremendous increase in the total amount of energy,
released from the fuel and available for accelerating
There is no voodoo involved in nitrous oxide. In effect,
using nitrous is no different from using a bigger carburetor,
a better manifold, a supercharger, or a turbocharger.
Understand that the air you and your engine breathe
is made up, at sea level, of 78% nitrogen, 21% oxygen,
and just 1% other gases. Nitrous oxide IN2O) is made
by simply taking the 2 major components of earth’s
atmosphere (in this case 2 molecules of nitrogen and
1 molecule of oxygen) and attaching them together with
a chemical bond. When the nitrous oxide goes into your
engine the heat of combustion breaks the chemical bond
to provide your engine more oxygen with which to burn
fuel. As you’ve read, all race engines operate
under the same principles:
more air (better breathing, supercharging, turbocharging,
or nitrous) plus more fuel in a denser vapor equals
Nitrous Oxide vs. Other Performance Products
Dollar for dollar, nitrous oxide offers the
most performance a consumer can buy. You could spend
thousands of dollars on carburation, a manifold, valve
train components, exhaust, pistons, porting, supercharging,
or turbocharging to get the same amount of extra horsepower
that a nitrous system would provide for just a few hundred
dollars. But this doesn’t mean you won’t
benefit if you also install other performance parts.
Once you have installed a nitrous system, all those
other performance parts just increase the nitrous power.
If you just have a few dollars and want lots of extra
power, the best choice is an NOS nitrous system.
Only nitrous is a part time power increaser. All 0f
the standard performance parts put additional stress
on the engine and burn more fuel all the time; not to
mention what a pain it is to ride around town with a
lumpy idle from a camshaft that is barely streetable.
Power on demand is one of the great things about a nitrous
system; it only works when the driven wants it. All
the rest 0f the time, the engine operates normally;
no extra stress, no extra fuel use, and no driveline
What You Get When You Buy a Nitrous Oxide System
Of all the components in your NOS system that you see
when you take it out 0f the box, there are three things
that you may not fully recognize until you have gone
through the installation process and used your NOS system
for the first time.
Integrity. We stand behind our products. If we claim
a system is capable 0f 100 horsepower, it’s because
we designed it that way, tested it that way, and manufactured
it that way. If you are willing to fallow our guidelines,
you’ll get the results that we say you’ll
Quality. There are a lot of things we do everyday here
at NOS. We test our products and systems on sophisticated
measuring equipment as well as the real-world environment
0f the vehicle it’s intended far. We pay strict
attention to the manufacturing procedures required to
maintain our high standards for components. We listen
to what you have to say about the performance of our
products along with your suggestions for new applications.
Our Tech staff relays your comments to our research
and development staff to constantly re-evaluate all
products to ensure they are up to date and effective
for the intended application.
We have been manufacturing nitrous oxide systems
for over twenty years. We have learned from our successes
as well as our failures. We take this knowledge and
apply it in very heavy doses to the products we design
and manufacture. Even though today may be the very first
day that you hove installed and used one of our systems,
you’ve got twenty years of nitrous experience
with you every step of the way. It’s there in
the box. You may not see it; but you’ll definitely
Nitrous Oxide and Emissions
Use of nitrous oxide (N20) doesn’t necessarily
increase the oxides of nitrogen (NOX) that pollute the
air, Of course, NOS makes “race only” systems
that are not legal for use on pollution controlled engines.
However, many NOS systems have received certification
for 50-state emissions legal use in the United States.
The approvals for use on emissions controlled vehicles
were obtained by independent laboratory testing which
proved that these NOS systems do not increase tailpipe
emissions in normal driving conditions. We recommend
only emissions legal nitrous kits for use on engines
subject to emissions and regulations.
Types of Nitrous Oxide Systems
The two most popular types of nitrous oxide systems
are spray bar plate systems, such as the Powershot,
Cheater, and Big Shot automotive systems (which use
a spacer plate between the carburetor and manifold)
and direct port. The plate adds nitrous and supplemental
fuel to the intake air stream through built-in spray
bars. Plate systems are used on automotive engines on
the street and in many racing classes.
Direct port systems use specially designed injectors,
Fogger nozzles, to add the nitrous and supplemental
fuel to each individual intake runner. These systems
can flow huge amounts of nitrous and fuel while distributing
it evenly to every cylinder. Multiple stage direct port
systems hove produced much more than 500 extra horsepower
on some pro racing engines. All NOS Direct Port systems
feature changeable nitrous and fuel jets for horsepower
adjustments and system tuning. Direct port systems are
used in both street and racing applications on virtually
every kind of engine. Some nitrous systems for fuel
injection are a variation of Direct Port technology.
Tuning Your NOS System:
A Few Important Points to Remember
Although this may seem like a very basic factor, failure
to thoroughly read the instructions is the number one
reason your system installations will not be successful.
Read ALL the instructions included with your system
BEFORE you do anything at all! You may find that you
need to change something on your engine or find that
we’ve designed something new that is different
from some of the systems you may have seen in a magazine
article. Save time and headaches by taking the time
to thoroughly read all of the instructional materials.
Call the NOS tech dept. if you have any questions.
Always start conservative. Follow our recommended jet
combinations and start with the lowest level if you
have an adjustable system. It only takes a few moments
to change the jets so don’t take unnecessary risks
by starting at the highest level.
Be realistic about how much power your engine will handle.
Don’t get carried away here. Only you know exactly
which components are in your engine. If you are unsure
about those components, you can call our tech line and
one of our highly experienced tech personnel can help
you to decide what is safe for your particular combination.
If you don’t know what's inside your engine, then
you are most safe by assuming that the components are
factory stock and choose the correct system for that
The power comes from Fuel. The additional power is set
by the amount of additional fuel your system supplies
while the nitrous system is in operation. If the fuel
isn’t there, the power won't be either and no
amount of nitrous or anything else can bring it back.
There are two controls typically available to manipulate
the amount 0f fuel available during system use; the
fuel jet size and the fuel pressure. The correct fuel
pressure is read while the system is flowing fuel. Some
fuel pressure regulators give false readings because
the pressure reading will creep up when the system is
not activated. When this happens, the actual flowing
fuel pressure will be much lower than expected and can
When problems with misfire or detonation are encountered,
ALWAYS reduce the size of the nitrous jet first! Remember
that the power comes from the fuel, not the nitrous,
so trying to cool things down by adding fuel simply
adds more power and complicates the problem. Carburetors
jetted over-rich run cooler and release less power.
Nitrous systems jetted over-rich will possibly just
release more power, so if you run into problems, reduce
the size of the nitrous jets first.
When you check your spark plugs for signs of how your
system is operating, CHECK EVERY SPARK PLUG, not just
the easiest plug to get to. No two cylinders ever run
exactly alike. Nitrous has the unique characteristic
of cleaning the spark plugs very well and leave them
looking like you just installed them. If there are any
signs of detonation such as tiny silver or black specks
deposited on the porcelain, reduce the nitrous jet size,
if the ground strap of the spark plug exhibits a bluish-rainbow
coloring, reduce the nitrous jet size. If the ground
straps shows signs of melting, reduce the nitrous jet
size and change to a spark plug with a shorter and thicker
If your system suddenly begins to experience problems
even though you haven’t changed anything, the
culprit is most often a clogged nitrous or fuel filter.
The instructions that came with your system contain
information about where the nitrous and fuel filter
screens are located. Check them periodically. NOS systems
are calibrated for optimum performance with a bottle
pressure of 900-950 psi. The pressure will change with
temperature. NOS heater kits are thermostatically controlled
to keep the bottle near 85 F to provide correct pressure.
Kits available for the most popular-sized bottles, with
both 12-volt and 110-volt heaters offered.
If you experience any problems you don’t understand
or can’t cure, don’t hesitate to call our
tech line. We’re here to help you get the most
from your NOS System.
Spark Plugs and Nitrous Oxide:
What Works, What Doesn’t, and Why
Over the years there seems to have been a great amount
of technical material written about the simple operation
of a spark plug and what they can do in relation to
the way an engine runs. There are a few basic characteristics
about spark plugs that you need to know to make an intelligent
choice about the correct spark plug for your application.
First, and most important; a spark plug must be of the
correct design to operate within the environment of
your engine not the other way around. This means that
the spark plug has virtually no influence on how the
engine burns fuel or runs in general. The correct spark
plug will simply survive the conditions present in your
engine. A spark plug must maintain a certain temperature
to keep itself clean. The wrong heat range can cause
an overheated plug or a fouled plug. The heat range
refers to the temperature 0f the ceramic material surrounding
the center electrode.
Lean air/fuel ratios are more difficult to light because
there are less fuel molecules in the area of the plug
gap when the plug is scheduled to fire; thus, protected
nose plugs were designed for late-model lean-burn engines.
Modern high-energy ignition also allowed larger plug
gaps. All the while this was happening, something else
happened. Something that no one seems to have really
noticed as the real culprit when the issue of factory
type plugs being used with nitrous comes up. We’d
like to clue you in.
Quite often, a factory type, wide-gap projected plug
will produce a misfire condition after only a few seconds
of nitrous use. The misfire is not due to the heat range.
The misfire occurs because the ground strap of the spark
plug becomes a glowing ember because it is too long
to dissipate the extra heat produced by a nitrous-accelerated
burn condition. The correct fix for this phenomenon
is to replace the plugs with one that has a shorter
ground strap. By doing this, you will shorten the path
for the heat being absorbed by the ground strap. You
can use the same heat range, you just have to find a
non-protected nose plus with a shorter and preferably
thicker ground strop.
If you only change the heat range of the spark plug
to a colder heat range, you may very well still have
the misfire problem. Since the length 0f the ground
strap is the cause the misFire, a colder spark plug
may have the same length of ground strap as the hotter
plug you replaced it with.
Spark plug gaps should generally be .030” to .035”.
Never try to gap a plug designed for an .060”
gap down to .035’. Find the correct non-projected
nose plug designed for an .035” gap.