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Discussion Starter · #1 · (Edited)
This is a Nitrous guide a local shop wrote, figured some of you can use it to get general info :) I know some of it is redunant :\ If you have any suggestions for a change or anything please let me know.

Nitrous 101
This page explains some of the features and benefits of running nitrous oxide on your car. Hopefully, these will be useful for those considering a nitrous installation, or just wanting to know what’s up. There are many different philosophies and opinions regarding the proper nitrous system. Please e-mail if you have positive question or suggestion that could improve safety or contribute to quality and performance.

How Nitrous works-Nitrous Oxide, Ny-Trous plus, NOS, Spray, Juice, Shot, Squeeze, Bang, Blow, Jizz, Laughing Gas.
It is a colorless, odorless gas composed of two (2) nitrogen atoms bonded to one (1) oxygen atom. The scientific abbreviation for nitrogen is N, and O for oxygen. The proper abbreviation for one nitrous oxide molecule is N2O. This where the familiar phrase “N-2-O” comes from. Nitrous Oxide is an oxidizer that is used as a carrier for oxygen. Mixed with the right ratios of fuel, and fed into the intake, it provides additional combustible material into the cylinders, creating more power. There are many ways to get the nitrous and fuel into the engine, the following describes typical applications that have proven successful.

The Basics-The nitrous is compressed to high pressure (900-1100psi) in a tank, in liquid form. From the tank (typically fastened down tightly in your trunk), a hose runs up to the engine bay. From there, an electrically controlled (like, by a button you push) valve called a solenoid is used to release the nitrous into the motor when you request it. At the same time, a fuel line in a "wet system," is controlled by another solenoid, and releases fuel into the motor. This provides the basic mechanism for the nitrous system.

Wet -vs- Dry-You may have heard the terms "wet kit" and "dry kit.".
A "wet system" is a nitrous system that mixes both nitrous and fuel, and feeds it (in a "Spray") into the intake. A "dry system" only feeds nitrous into the intake, and tricks the existing fuel system to add the fuel.
Throttle Body Plate-This is a 1/2" thick plate that's mounted between your throttle body and intake manifold. Both nitrous and fuel lines are connected to it (so it's a wet setup) and the plate combines them and sprays into the intake.

Fogger Nozzle-A nozzle can support either a single line for nitrous, or a pair of lines for nitrous and fuel, and sprays a fine mist into the intake.

Direct Port-The ultimate setup- each port is tapped and threaded specifically for a nozzle at each cylinder. nitrous and fuel lines to spray directly into the cylinders. This setup typically provides the most horsepower for extreme race applications.




Triggering the System-Of course, you don't want the system to be running all the time - a 10lb bottle will last you less than a minute, if it's open. Typically, you want the system triggered on while you're at the track, at WOT (wide open throttle), and at relatively high rpm's (see "Safety" for why). To make that happen, you'll typically want to wire, in sequence, several switches. I won't describe the specific wiring here, but you'll have some or all of the following:
1) Arming (On/Off ) switch. 2) WOT switch is a micro switch installed on the throttle system, that activates the circuit only when your foot is on the floorboard. 3)pushbutton in the car, probably on the shifter 4)"Window Switch" (see "Safety" for details) that closes the circuit only when the engine RPM is between a certain range (like 3000-6000) that you decide is acceptable 5) Fuel Pressure Safety Switch

Nitrous Controllers-The system to trigger described above is a basic "single stage" setup. The nitrous is either on or off, and when it's on, the full volume dictated by the jets is sprayed into the engine. There are other applications that are full race or multiple stage nitrous system that require more detailed management at higher rpm, with time-based systems, which delay the nitrous flow for some time after you launch, etc. These Nitrous controllers are a great addition to any nitrous system and can help to safeguard the engine from Lean-Condition.

Safety-Use all the safety mechanisms you have available. They are cheap and very effective. Components such as Fuel Pressure safety Switch, Rev limiters, EGT sensors, Window switches, etc. are relatively inexpensive ways to protect your investment.

What Can Go Wrong?-Well, a lot can go wrong, but hopefully you'll have adequate safety mechanisms built in to protect your motor when it does. The main thing that can go wrong is adding nitrous into your engine without compensating fuel. This extreme lean condition is disaster for the engine, and you're not likely to get a second chance - at least with the same engine. Conversely, adding extra fuel without nitrous is not particularly bad for the engine, so you can imagine, it's safer to start with the car running rich (too much fuel), then lean it back from there. Some examples of problems you might encounter include:

Ignition RPM limiter-The rev limiter is implemented by cutting the signal to the fuel injectors so the cylinders have no combustion. If you're running a dry system, which depends on the fuel injectors to provide compensating fuel for the nitrous, losing fuel this way is the ultimate disaster. An after market ignition will typically implement the rev limit by cutting off spark rather than fuel, which is a much safer implementation of the rev limit. Typically, you'd get your stock PCM programmed to set the rev limit up higher than you'll ever expect to go (like 7000RPM), and use the setting on the after market ignition as your actual rev limit.

Window Switch-This electrical device provides an open or closed circuit based on the engine being between two RPM values (hence "window") that you chose, so that you'll only flow nitrous in this range. Why would you do that? Well, for two very different reasons.
1) At low RPM, think about what's going on: you're spraying nitrous into the intake at a constant flow. That is, the nitrous bottle and solenoids have no idea what RPM you're at, and they're just pushing it into the intake at a constant volume. Inside the engine, though, the nitrous and fuel combination is being sucked into the cylinders during every stroke. The net result is that at low RPM, you're getting far more of the mixture into the cylinders. At 3000 RPM, for example, you're getting twice the amount as at 6000 RPM. So, you can imagine that running nitrous at, say 1000 RPM, is far more stressful on the motor as at 3000 RPM, and typically causes a "nitrous backfire" - meaning that the nitrous/fuel combination can explode in the intake manifold (rather than the cylinders) - a bad thing. So that's why you don't want the system triggered at low RPM.
2) At high RPM, the situation is easier to explain. Given the discussion of the rev limit above, you may just want the nitrous system to cut off before hitting that rev limit. If you've got a stock ignition, you certainly want a window switch. If your rev limit is implemented by an aftermarket ignition, it's perfectly safe for the motor to run nitrous during the rev limit. It's not particularly easy though, on your transmission or clutch to have all that power during the shift, which may be a reason to keep the window switch set a bit before you shift.

Fuel Pressure Safety Switch (FPSS)-This is a device that's plumbed into the fuel system, and provides an open or closed circuit based on availability of fuel pressure. It can be used in the triggering circuit to make sure the system isn't on when you've got a fuel problem. Typically, you only use it to switch off the nitrous solenoid; turning off the fuel solenoid as well can start a cycle of switching the solenoids on and off while the pressure raises and drops in the fuel system when you're switching the solenoid on and off. Let the pressure build up in the fuel lines when you open that solenoid, and when it's high enough, the nitrous solenoid will open. The switch can be used whether you've got a wet or a dry system. You can adjust the pressure at which it triggers by using an allen wrench on the back of the switch (loosen the screw lowers the pressure threshold).
You want to set the pressure on the FPSS, such that if the pressure drops about 10psi the nitrous system will shut off. On a wet EFI system, this will be around 33psi, and on a dry system I'd leave the switch just above stock, say 45psi.
To set the threshold pressure, you've got a few options"
Connect enough plumbing so that you can have the FPSS installed at the same time as a fuel pressure gauge. Turn the key on to pressurize the fuel system, then turn it off. As the fuel pressure bleeds down, monitor the continuity across the FPSS contacts (disconnect them from the rest of the nitrous system) and when the pressure reaches the level you're interested in, adjust the screw on the back so it just balances back and forth between the continuity signal.
You could use an air compressor, with the appropriate fitting for the FPSS. Remove the FPSS from the car, and thread it onto the compressor. Set the compressor for the pressure of interest, and measure continuity as above.
If you can't do option #1 above because you don't have two available ports, first thread in the pressure gauge, and cycle the key. Then time how long it takes for the pressure to bleed down to the correct level. Then disconnect the pressure gauge, install the FPSS, and do the process against the clock rather than the pressure.

Timing Retard-A nitrous/fuel mixture increases the burn rate in the cylinder, and typically adding a few degrees of timing retard is recommended for safety. A rule of thumb is two degrees per 50hp of nitrous, but this will also reduce the power generated. When I tune my system, I monitor engine knock, and retard the timing only enough to eliminate the knock, which is usually about one degree per 50hp. At the track, under harder conditions (actually pulling the weight of the car, possibly higher outdoor temperatures, etc) I'll add a degree of retard.

High Octane Fuel-High octane gas (e.g. 100 or more, unleaded) will also slow the burn rate in the cylinder. This will provide another way, similar to retarding timing, to avoid knock. I only use nitrous on a 50/50 mix of 92 octane pump gas and 100 octane racing gas. Make sure it's unleaded, of course, or you'll destroy your O2 sensors.

By the way, watch out for Octane Boost claims. Typical claims are "8-10 points of octane boost for a tank of gas." You should be aware that these "points" are tenths of a point of octane as you'd purchase at a gas station. So the above example will raise your octane from 92 to 92.8 or 93, not 100-102 as you might think.
Don't assume that if high octane fuel helps on nitrous motors, that it'll help your naturally aspirated motor too. A naturally aspirated motor is tuned for a particular octane of gas; adding more doesn't help one bit. Save your money.
Nitrous Filter-A simple part, but essential in any nitrous system. This filter is added in-line to your nitrous line, between the tank and the solenoid. Install it as close to the solenoid end as is convenient. It will trap any small particles that may come through the line, much like a fuel filter. A common solenoid failure is due to some particle jamming it open.
Fuel Systems-Your fuel system is the most important part of the system. As I hope is clear by now, the worst scenario in a nitrous system is a lean air/fuel mixture. The solutions to a good fuel system depend on the type of nitrous system you're using.
On a wet system, you simply need to ensure that your fuel system can supply adequate fuel, at standard (~45psi at WOT) pressure. A stock f-body fuel pump can usually supply enough fuel for around 450 total horsepower to the motor; any more and you want to get a larger pump. Much more than 650hp and you'll want larger fuel lines as well.
On a dry system, not only do you want adequate fuel like the wet system, but on an typical setup the fuel is added by raising the fuel pressure, which forces more gas through the injectors. In this scenario, it's typically recommended that you replace the stock fuel injectors with better quality (not higher rating, just better, like Bosch) injectors. These injectors are able to handle the increased fuel pressures necessary.

Spark Plugs-Generally you want to use copper spark plugs or iridium as opposed to the stock platinum ones. You also want to reduce the gap from the stock 0.050" down to 0.035"-0.040". I've received a couple notes on why you use a smaller gap. "The reason you want a smaller gap is because of ionization. If you change from the typical air (78%nitrogen, 21% oxygen)/fuel ratio, a given gap requires more energy to ionize the mixture, resulting in less energy in the spark, if you even get a spark. You could also increase the coil voltage instead of decreasing the gap, but I think using a smaller gap would be preferential since the spark time will be smaller." and also this message: "The reason that you will close the gap on your spark plugs is because when nitrous is added, it raises the cylinder pressure, much like a supercharger. Therefore "blowing" the spark out. When you close the gap it cannot put out the spark as easily."

Testing Solenoids-I mentioned failed fuel or nitrous solenoids doing damage. Some of the issues here may be hard to cover with only other safety devices. I recommend you wire your solenoids with spade clips, so you can easily disconnect them, and test them on a regular basis. Simply disconnect them from the rest of the wiring, then ground one side, and connect the other side to 12V, and listen for the click-click to make sure they open and close. Some folks will also use two nitrous solenoids, in-line, which will ensure that both would have to fail before the flow would fail to stop. Of course you still need to test this setup, to ensure one isn't stuck open.

Tuning-All of the kit systems will come with a couple tuning setups, labeled "50-shot", "100-shot", etc. These are tuned to provide 35, 50, 75 or other horsepower amounts, usually measured at the crank (i.e., measured on a chassis dyno you'll get a bit less). I consider these a starting point, and certainly good for your first passes (hopefully you'll make these with the lowest power, until you tune the system up). Once you've got the system installed and functional, though, tuning it is paramount, before running any serious power through it. I really recommend you do this tuning right away, even though the temptation will be strong to just go out and enjoy the power. This is the time you're very likely to do some serious damage to the motor, it's important to get it set up right.

Getting Started-I'm not going to go through a bunch of details on tuning here, other than to mention some ideas. You've got a plumbing system to test, as well as an electrical system. You'd like to test each component of both systems, to verify that it's correctly doing it's job. I suggest doing most of this in your garage, with the nitrous and fuel lines removed from the intake, and pointing (or held) into a rag. Keep in mind the nitrous line will give a good kick under pressure, so don't just leave it loose to whip around. You can test your WOT switch easily enough, your window switch (maybe set the window range at a lower rpm for the test, so you don't have to rev up to your red line). To test your fuel pressure switch, you'll need to verify it's got a closed circuit when the engine is running (showing adequate pressure), but you'll also want to verify that it opens the circuit as fuel pressure drops. There are a couple ways to do this. On my car, the fuel pressure bleeds off at about 2psi per hour. So if I switch the engine off, I can use an ohm meter to check continuity across the FPSS connections, and within a couple hours it should switch off. You can also test the FPSS on an air compressor, by generating the pressure you want for the FPSS, and monitoring that it switches at the right point.
For the plumbing, you of course want to verify that there are no fuel or nitrous leaks in the system. You should be able to leave your nitrous bottle open for hours without losing bottle pressure. On the fuel side, of course a fuel leak may be the most disastrous possibility, so check this first by pressurizing the system (turn the key to "acc" but don't start the car) and feel around all the fittings.
I haven't listed all possibilities, but hopefully given you an idea of where to start testing. Once everything seems to check out, put in a set of 50hp jets, and move out on the track.

Jets-All nitrous systems use "jets" inserted in the fuel or nitrous lines to limit the flow. These jets have openings of a specific size, measured in thousandths of an inch. So a "35 jet" is a jet with a hole drilled 0.035" through it. Increasing a nitrous jet size will make the system run more lean, increasing the fuel jet size will make the system run more rich.
There's also a good website http://cosmik.org/calculators.htm with a jet size calculator on it for a wet setup (where you're metering the fuel and nitrous yourself). It will give you jet sizes based on desired horsepower, fuel and nitrous pressure. I recommend you use these as a target, maybe start a bit richer than shown.
I don't have information here on the use of a jet to apply vacuum pressure to a fuel pressure regulator, as in the NOS 5176 kit. The use of jets for this purpose, and calling them "fuel jets" is NOT related in any way to the normal use of fuel jets in a wet system, and I'm not aware of algorithms that would allow you to select these jets in combination with nitrous jets, to create a certain amount of horsepower. Contact the nitrous kit vendor for recommendations.

Scanner Tuning-A PCM scanner (Diacom, Autotap, etc) is crucial to successful tuning of your nitrous system. I run most of my nitrous passes while logging with an Autotap, and also use it at the dyno. You'll be monitoring the oxygen sensor voltages, knock, etc, and adjusting the jets to provide the best combination. Note, though, that the stock oxygen sensors are not particularly good, and a wideband O2 sensor (say, at a dyno) is much better to use if you have access to one. Typical O2 values should be around 860-880mv (higher is richer) when running the motor normally aspirated, and I try to tune mine to 900-940 on nitrous. As mentioned above, you'll adjust jet sizes up or down to enrich or lean out the mixture. You'll probably see some knock during a shift, but should see none otherwise. You can add timing retard to reduce knock.

Dyno Tuning-Doing your scanner tuning at a dyno provides another benefit, since you can see the power the engine is generating, while you tune the system. It also makes the whole tuning process easier than racing up and down the track, swapping jets in the pits, waiting in lines, etc.
How much can I run?-On a stock V8 motor, 150hp appears to be the limit. 125hp is probably a "safe" setup, assuming it's working well. A built, forged motor can take quite a bit more, 200-250hp is probably reasonable, but you'll be going to direct port if you want more power. On a six-cylinder motor, 75-100hp, while stock 4 cylinder can take from 35-75hp. These seem to be the highest "safe" setups. Of course, I use the term "safe" very loosely here, to mean that folks have run this amount of nitrous for quite a while without blowing up their engines.

B]Miscellaneous Options[/B]


Purge-Most nitrous systems are build with a purge feature. The purpose of a purge is to get liquid nitrous oxide up to the front of the car, filling the hoses with nitrous rather than air. To do this, another solenoid is used, but rather than shooting the nitrous into the motor, it's usually shot up over the hood, or out of the grill so you can purge until it creates a nice fog. It also looks real cool . Of course, no fuel is used during a purge.


Bottle Heater-It's virtually mandatory that you install your nitrous system with a bottle heater, which is used to raise up the temperature of the bottle, and therefore increase the pressure at which the nitrous is delivered. If you don't use one, your pressure will quickly drop and won't supply the volume of nitrous your vehicle was tuned for.

Remote Bottle Opener-Normally, your nitrous bottle should be kept closed, with no pressure in the nitrous lines. But when you're lined up against that guy that just looks a bit too fast, you'd hate to say "excuse me, do you mind if I hop out and open my bottle in the trunk?". Easy solution, get a remote bottle opener! Most vendors have such a device, which allows you to open the bottle electrically via a switch on your dash.

Collateral Damage-You can break tons of other parts on your car by running nitrous, or any other large power addition. Running slicks at the track will just accelerate the damage. Here are a few things to keep in mind.

Clutch-The huge torque spike at low rpm's is particularly hard on clutches. I had to buy a new clutch as soon as I made my first pass with nitrous on slicks. Keep in mind, on a manual transmission car, you're likely to need one too.

Rear End-Not unique to nitrous, but certainly a common failure on high horsepower cars, is the rear end. A 4th generation f-body, with a stock 10-bolt rear end, is not going to last long on nitrous. Plan for an expensive (~$2,000) upgrade at some point.
Tires-With all the extra power, you'll have trouble hooking up with any traction, especially on street tires. You'll probably have to use drag radials at least, or slicks if you're adding any significant power.


NITROUS FAQ
Taken from: http://www.nitrousdirect.com/nitrous.html

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
 

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Discussion Starter · #2 ·
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?

A: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

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?
 

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NewbTuner said:
I just noticed fgnick posted a 101 in the past, im sorry :( the guide i posted does have some of the same info but also has additional info, if there is something you still have a question about i suggest checking out...

http://www.8thcivic.com/forums/showthread.php?t=34737

:)
Nothing wrong with repeating good stuff. :thumb:
 

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If someone could run a compression test on their Civic after running with a bottle for over a month.

And everything seems undamaged, id put my bottle on my car.

But since no1 finds the time to do so, i think many people will not even go close to Nitrous Oxide due to damage.

Personally, all you people can say good things about having Nitrous and how its not gonna hurt my Motor, but in the end, in the back of my mind I say it does.

Unless someone can prove to me with a Compression test, or some sort of test, im selling my bottle.

I really wanna put it on my car though, would be nice to have that extra power.
 

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SpeedDemon said:
If someone could run a compression test on their Civic after running with a bottle for over a month.

And everything seems undamaged, id put my bottle on my car.

But since no1 finds the time to do so, i think many people will not even go close to Nitrous Oxide due to damage.

Personally, all you people can say good things about having Nitrous and how its not gonna hurt my Motor, but in the end, in the back of my mind I say it does.

Unless someone can prove to me with a Compression test, or some sort of test, im selling my bottle.

I really wanna put it on my car though, would be nice to have that extra power.
Stress is stress whether it be nitrous, supercharging or turbocharging. Any time extra pressure is introduced into a cylinder, more stress is involved.

From the sounds of it, I think you would be better off going N/A. Get a good race header like the Buddy Club or Vibrant, a HFC, and a good cat back exhaust. Find a good CAI and get the Hondata.
 

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NitrousG35 said:
Stress is stress whether it be nitrous, supercharging or turbocharging. Any time extra pressure is introduced into a cylinder, more stress is involved.

From the sounds of it, I think you would be better off going N/A. Get a good race header like the Buddy Club or Vibrant, a HFC, and a good cat back exhaust. Find a good CAI and get the Hondata.

Trust me, I got all that.

Im not new at this.:wavey:
 

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SpeedDemon said:
Trust me, I got all that.

Im not new at this.:wavey:
Wow, you have all of the above and still want more? If you get the Comptech Supercharger, you could keep all of the above and ramp up your power even more. I still feel nitrous is the best bang for the buck, but I understand your reticence. It's best to trust your instincts.
 

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Why would you wait on someone elses compression test before you put N2O on ur car? Ur car is your car,.....Put the N2O on there. Set it up right, run a shot that suits you and enjoy it. A 55 or 75 shot isnt going to blow out piston or oil rings and make cylinders lose compression. Especially on a new motor.
 

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Why would you wait on someone elses compression test before you put N2O on ur car? Ur car is your car,.....Put the N2O on there. Set it up right, run a shot that suits you and enjoy it. A 55 or 75 shot isnt going to blow out piston or oil rings and make cylinders lose compression. Especially on a new motor.
Well said. It is an urban legend that lower shot of nitrous will damage your motor. Some things just go away including the myth that nitrous will blow up your motor. A compression test is not necessary on a new car as you said. If my motor had 50,000 hard miles, yes, I might do a compression test before running nitrous, but a new motor has tight clearances.
 

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Sorry for resurrecting an old thread but, in the second post, I found something I'm not quite understanding...

NewbTuner said:
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.
So.....If I'm reading this correctly, I don't need to use 92 octane if my car doesn't call for it by OEM.....???????

Furthur elaboration would be greatly appreciated...:thumb:
 
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