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Why its jetted @ Solenoids
Why we cant use Oxygen!
V8 into Ford Sierra!
The Nitrous FAQ:
FAQ (Frequently Asked Questions)
Everything you wanted to know about N2O
FAQ (Frequently Asked Questions)
There is more
RUBBISH talked about Nitrous Injection than all the other types
of tuning put together. Read ALL of this, because its all
Do not listen to your pub or forum "expert" or "engine guy" or racer because most of these people know very
little about this subject. Especially when it comes to building your own
systems or the shortcomings of the US based systems.
This is a "Nitrous Oxide Injection F.A.Q."
similar to ones found all over
The difference is that this one is
correct and accurate and more detailed than the typical FAQ found elsewhere. And
it relates to MY systems much more than the rather agricultural US clones.
How Does Nitrous Oxide Work?
Several ways at once. 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 and during initial combustion), it breaks down and releases
its load of extra oxygen, However, it is not this oxygen which creates more power, but the ability of this oxygen to
burn more fuel.
Quick note here: Contrary to popular opinion DRY Nitrous systems ALSO add more
fuel one way or another or they couldn't give more power and would in fact
damage your engine very quickly. They do this normally by fooling the stock
vehicles injection system into adding the extra fuel. Personally I think all dry
systems are a liability and should be avoided at all costs! for a bunch of
By burning more fuel, higher cylinder
pressures are created and this is where most of the additional
power comes from. Secondly, as pressurized nitrous oxide is
injected into the intake manifold, it changes from a liquid to
a gas as it expands. This boiling affect reduces the temperature of
the nitrous oxide to minus 127 Degrees F or -88 Degrees C. This "cooling affect" in
turn significantly reduces intake charge temperatures by
approximately 60-75 Degrees F or over 20 Degrees C . 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 nitrogen that was also released
when the Nitrous split up performs an essential role. Nitrogen acts
to absorb the heat and expand with the increased cylinder pressures leading
to a controlled combustion process and better slower heat
release. In other words you get more pressure to push down the piston.
note with ref to the above.... With a correctly set up system, the
PEAK cylinder pressure wont be very much higher than the stock engine
already had. The key here is that you MUST retard the timing sufficiently
for this to be the case.
What we are trying to achieve (at
least on a road car) is extra power with no engine problems. Retarding the
ignition means that you get a much higher average cylinder pressure but a lower
peak pressure. Retarding it a lot means huge doses of nitrous is "safe" on stock
motors. This means your engine doesn't see much more stress or pressure than it
did without nitrous.
Also if the Nitrous Fuel ratio is
set adequately "over" rich then temperatures remain pretty low as well.
Admittedly this isn't the most efficient use of the available nitrous but it
keeps your road car or bike totally reliable whilst getting 80 percent as much
power as a totally "leaned out" set up. Understanding this means you can set up
your car or bike safely. This sort of accuracy isn't even possible with most
commercial systems due to a large number of things not least being
Why its jetted @ Solenoids
Oxide (N20)? Not NOS!
Nitrous oxide injection has become a very popular option for
today's performance enthusiast for several reasons:
N20 offers you more performance per £ / $ 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 unlike conventional tuning parts.
Q: Why not
serious reasons! A whole page here explaining why...
Why we cant use Oxygen!
Q: Will N20 affect engine reliability?
A: Theoretically not.
In moderate doses, properly set
up (see above) and used by someone that understands the system then it
should not have any adverse effects. In some cases the
opposite could be argued. However someone using a cheap commercial dry kit
with little knowledge of what's going on will likely break something sooner or
later. Knowledge as always is power.
But probably in any case... One day its
inevitable your engine will break, they almost all do so if
you drive it like you hate it! No engine goes forever so
just accept it! If it has N20 fitted it will inevitably get
And It may well be nothing to
do with the nitrous and usually isn't!
Q: Can I simply bolt a N20 kit onto my stock engine?
A: Yes. Provided its fit, healthy and one or two simple
precautions are observed then no problem In fact Stock engines
are often best!
Q: What are some of the general rules for even higher H.P.
A: Generally forged pistons are one of the best modifications
you can make. Retard ignition timing by a few 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".
Q: How much performance improvement can I expect with a
Loads..... Depends on jetting. You simply choose!
Literally 400 to 600 percent is easily possible. If you know what you are doing.
Q: How long will the bottle last?
Approximately 10bhp per lb per min. You
decide! You choose bottle size and power increase. So a 2.25 lb
bottle on a bike will give just less than a minute with a
25BHP increase. That's
a LONG time when it goes from zero to 150mph in ten seconds!
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... I tried
it several times in both the V8 powered Ford Sierra and my GSX 1100 Suzuki
bikes. They run out of revs and gears before the bottle gets empty.
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 off the line when
Q: Will I have to re-jet my carburettor on my car when
A: No! The N20 system is independent of your carburettor and
injects its own mixture of fuel and Nitrous.
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 inside the engine.
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.
Q: Where can I get my bottle refilled?
A: There are many performance shops that can refill your
nitrous bottle. There are many suppliers, see the "REFILL"
Q: Is there any performance increase in using medical grade
A: None! All the same, Medical grade simply does NOT have the
bad smell chemical added that Race grade stuff does. I don't recommend sniffing
it anyway as it gives you a headache...
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. Its pointless anyway unless your
vehicle is turbocharged.
Q: Does nitrous oxide raise cylinder pressures and
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
You want pressure, its what
makes the car/bike faster, but you don't want the heat. Go
Richer and more retarded the more boost you add!
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 psi. Or jet accordingly to
correct the situation. Live in a cold place? Used a bigger nitrous Jet...
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 hugely. Boost is usually increased
as well; adding to even more power.
Q: What effect does nitrous have on an engine with considerable miles on it?
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.
If you are unsure have a Garage compression test, and oil
pressure test it and get the Mechanics opinion of its
Q: Will the use of nitrous oxide affect the catalytic
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 and the extra heat may in fact clean it up and improve its
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. Nitrous kits are used in applications
from relatively low compression stock type motors to Pro-Modified, which often
exceed 15 to 1. Generally, the higher the compression ratio, the more ignition
retard, as well as higher octane fuel, is required.
Q: What type of cam is best suited for use with nitrous
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. For road cars or bikes the stock cam is great!
Q: What type of nitrous system is better; a plate injection
system, single point or a direct port injection system?
A: Neither is better. The best system is whatever "suits" your
induction system the best.
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 carburettor 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 if in doubt.
Q: What are the advantages of using nitrous compared to other
A: DIY System?
Its almost free!
www.nitrous.info The cost of many other performance options can put you in
the poorhouse. 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.
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.
Q: What is the function of the blow-off safety valve on the
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.
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. As a short term cheap fix if you have problems close the plug gap
by 25 percent.
FAQ Technical Fact/Fallacy (Don't
where this one came from originally but now I have modified
it, it's ALL true!)
injection has become one of the most popular methods of
increasing the power output of an internal combustion engine,
and justifiably so. Nitrous oxide (N2O) injection is simple
precisely metered N2O and gasoline are force-fed into the
engine, supplementing the normal air/fuel mixture to release
more work-producing heat during the combustion process. The
only equipment required is an N2O storage tank, a pair of
solenoid-actuated valves to control the N2O and gasoline flow,
nozzles (or spray bars) to distribute the N2O and gasoline,
and the various hoses, lines and wiring to connect the system.
Engine disassembly is not required for installation-and the
system can be removed for resale or transfer to another car at
any time. The cost of a new professionally prepared system is
reasonable (between $400 and $600 US in most cases), and the
power increase is dramatic (usually in excess of 100 hp for
most street systems).
As popular as
N2O systems have become (industry estimates are that over
20,000 systems are now in use!), many enthusiasts still think
of N2O as some sort of evil black magic. Honest and reliable
information about the effects of nitrous oxide, the care and
installation of N2O systems and tuning tips regarding N2O use
has been practically nonexistent. Instead, the bench racers
pass along inflated rumours of unbelievable power gains that
rival a Saturn rocket, and incredible horror stories of
vehicles supposedly erupting in fireballs that would make a
hydrogen bomb seem small.
N2O is explosive and a fire hazard.
FACT: N2O will not burn, nor is it a fuel. It is merely
an oxygen-rich compound that supports the combustion of
additional fuel. That's why additional fuel is injected along
with the N2O on all N2O systems. It is true that if N2O is
added to a combustion process already in progress, the extra
oxygen may cause rapid, uncontrolled combustion, thus raising
the peak temperatures produced.
N2O adds octane to the fuel being used and reduces detonation.
FACT: N2O does not increase the octane of the fuel
being used. However, nitrous oxide injection may suppress
detonation due to the intercooling effect of the
depressurizing of the compressed N2O and by the introduction
of extra gasoline. Most N2O systems intentionally add about 10
percent excess fuel as a safeguard against accidentally
leaning the mixture. The extra fuel acts almost like water
injection to cool the mixture and dampen detonation.
Premium fuel must be used with N2O injection.
FACT: The purpose of N2O injection is to support the
combustion of extra fuel, thereby releasing more
work-producing heat in the combustion chambers. Consequently,
maximum cylinder pressures with N2O will be higher than when
it isn't in use. Extra cylinder pressure does tend to cause
pre-ignition and uncontrolled combustion, but as previously
described, N2O injection also tends to suppress detonation.
With most street N2O systems, these two opposing forces tend
to cancel each other out, which means you can continue to use
the same octane gas that was acceptable before the N2O was
added. Because competition N2O systems inject a greater
quantity of N2O and gasoline than do street N2O systems,
cylinder pressure is frequently raised to the point where a
higher octane fuel (or anti-detonation additives) must be
N2O will melt pistons, rings and valves.
FACT: If the N2O system has been properly designed to
supply the correct amount of gasoline along with the N2O,
combustion temperatures will actually be lower than when N2O
isn't being used, so damage from elevated temperatures does
not occur. Since the purpose of N2O injection is to make more
heat, this may sound like a contradiction, but it isn't. With
N2O, the total amount of heat energy released is greater, but
the peak combustion temperature is lower. Think of it this
way: A huge oil storage tank burning at an average temperature
of 1000 degrees releases a lot more energy than a small
acetylene torch with a tip temperature of 2000 degrees. That's
a comparison by extremes, but in an engine with N2O injection,
each cylinder might be burning 25 percent more fuel at a
temperature of 1400 degrees than the engine would without N2O
at 1460 degrees.
Claims of engine damage while using N2O are not totally
fictitious, however, since if cylinder pressure does rise
above the octane tolerance of the fuel being used, detonation
occurs, and that will damage pistons, rings, etc.
Freezing the N2O tank increases N2O flow and the power output.
FACT: Whenever a pressure vessel is cooled, internal
pressure drops. Most N2O systems are designed to work with
tank pressures of 600-800 psi, which is the approximate
pressure of a normal bottle at room temperature (approximately
72 degrees). If the bottle is cooled below room temperature,
the pressure quickly falls, and flow would be reduced to the
nozzles. For example, a bottle that had 800 psi at 75 degrees
would fall to 450 psi at 30 degrees, and only 275 psi at O
On the other side of the coin, heating the bottle increases
the pressure, but heat also tends to make the N2O vaporize in
the line between the solenoid valve and the discharge nozzle,
which upsets metering and reduces N2O flow. Ideally, the
bottle and lines should be kept at room temperature. At the
drags, some cooling of the bottle may be required to achieve
this while the car sits in the staging lanes, but a damp cloth
or towel wrapped around the bottle will generally be all
that's required. If you really want to pursue additional
cooling, chill the line between the solenoid
valve and the nozzle, and keep that line as short as possible
to reduce the likelihood of vaporization before the discharge
N2O injection in the individual manifold runners, as close as
possible to the cylinder head, is more effective than
injection immediately below the carburettor.
FACT: Although it used to be thought that direct port
injection improved performance by assuring equal distribution,
subsequent vehicle and dyno tests have shown that
under-the-carb injection seems to provide a greater power
increase since the gasoline has more time to vaporize as it
travels down the intake runners. But the difference is very small!
As long as there's still pressure in the N2O bottle, some N2O
is left and the system will function properly.
FACT: An N2O system meters and discharges liquid N2O
when everything is working properly. When filled, an N2O
bottle is only 68 percent full of liquid. The remaining space
is specified as an expansion area. Additionally, an N2O tank
needs a siphon tube to assure that the pressure head in the
expansion area forces liquid N2O out into the lines, rather
than gaseous N2O. When the liquid N2O is expended, it is not
uncommon for the tank to still have 600 psi pressure, so
pressure alone is not an indicator of N2O. Gaseous N2O is
clear, whereas liquid N2O, vaporizing as it leaves the nozzle,
will be white in colour. This is a more accurate indication of
whether there is still liquid N2O in the bottle.
You need a prescription to buy N2O.
FACT: A prescription is not required to buy industrial
grade nitrous oxide for automotive use. Nitrous oxide is
available at most compressed gas suppliers, such as welding
gas supply houses, but we have heard of isolated cases where a
particular dealer who doesn't want to be bothered servicing
hot rodders will use the excuse that you must have a
prescription. If medical grade N2O (the only difference is the
sterilization of the bottles) was being sought, then a
prescription would be required. To make the purchase of N2O
even easier, many speed shops are now refilling N2O bottles.
If you live in a really isolated area or are confronted by an
uncooperative dealer, the N2O system manufacturers will refill
your tank, but of course, shipping the bottle back and forth
is an inconvenience.
N2O requires no special tuning adjustments.
FACT: Force feeding N2O and extra fuel into the
combustion chambers increases the density of the mixture,
which increases the burning rate of the mixture. Consequently,
it is frequently necessary to retard the ignition timing
slightly for optimum results. The greater charge density also
imposes a heavier load on the ignition system, so a good
high-energy ignition system, with good spark plug wires and
clean spark plugs is essential. If a competition N2O system is
being used, the plug gap should smaller, and plugs one or two
heat ranges colder than stock are recommended to help
dissipate the extra heat of combustion.
You can't build your own N2O system
YES!!! If you're sharp enough, you can as LOADS of people have
done using these pages!
If tank pressure exceeds 850 psi, the solenoid valves will
leak, flooding the manifold with N2O.
FACT: The solenoid valves used on some systems are
rated at 850 psi working pressure. Other systems have
solenoids with even higher ratings. In truth, the ratings are
conservative and even the lowest rated solenoids being used
will work at pressures up to 1500 psi. The working pressure
has nothing to do with the pressure at which the solenoid will
leak, since pressure actually helps close the valve, so the
higher the pressure, the more tightly it seals. The working
pressure or rating only refers to the solenoid's ability to
open the valve against the pressure in the system.
N2O will blow up your engine.
FACT: If the N2O solenoid valve leaks or malfunctions
while the engine is off, the manifold can become charged with
a very lean mixture of N2O and gasoline. When the ignition is
first turned on, a spark impulse may occur in a cylinder where
the intake valve is standing open, igniting the mixture, which
will virtually explode. Carburettors have been blown off
manifolds in such situations. Consequently, it is advisable to
turn off the main valve on the N2O tank whenever the car is
going to be parked for several hours. If a leak is ever
suspected, simply remove the coil wire and crank the engine
for about 10 seconds to clear any N2O contamination.
You can smell leaking N2O.
FACT: Nitrous oxide is an odourless, colourless gas.
There's no limit to how much power you can make with N2O.
More N2O and more fuel equates to more power, but there's a
definite limit to how much any engine will stand. It all comes
down to: How fast do you want to go? And at what price?
the term NOS is incorrect as this refers to an specific
company (called Nitrous Oxide Systems, in the US)