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 releases its load of 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 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 damper" the increased cylinder
pressures leading to a controlled combustion process and
better slower heat release
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 £ / $ 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: Will N20 affect engine
reliability?
A: Theoretically not.
In moderate doses, properly set up and used by someone that understands the system then it should not have any adverse effects. In some cases the opposite could be argued.
But probably... 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 the blame!
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.
gains?
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
nitrous system?
Loads..... Depends on jetting.
You simply choose!
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. Thats 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...
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 drag racing.
Q: Will I
have to re-jet my carburettor on my car when adding
nitrous?
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"
page.
Q: Is there any performance increase in using
medical grade nitrous oxide?
A: None! All the
same, Medical grade simply does NOT have the bad smell
chemical added that Race grade stuff does.
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 & Super Chips
do make special chips for use with
nitrous.
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 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.
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.
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 condition.
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.
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. For more specific
information talk to a qualified
technicians.
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.
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 performance
options?
A: 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
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.
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.
FAQ Technical Fact/Fallacy (Don't know where this one came from originally but now I have modified it, it's ALL true!)
Nitrous oxide 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.
FALLACY: 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.
FALLACY: 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.
FALLACY: 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 used.
FALLACY: 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.
FALLACY: 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 degrees.
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 nozzles.
FALLACY: 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!
FALLACY: 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.
FALLACY: 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.
FALLACY: 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.
FALLACY: You can't build
your own N2O system
FACT: YES!!! If
you're sharp enough, you can as LOADS of people have done
using these pages!
FALLACY: 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.
FALLACY: 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.
FALLACY: You can smell
leaking N2O.
FACT: Nitrous oxide is an odourless,
colourless gas.
FALLACY: There's no
limit to how much power you can make with
N2O.
FACT: 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?
