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Discussion Starter #1 (Edited)
alright, since this board seems to be lacking in the nitrous department, I've decided to post an FAQ on nitrous and do a little rumor squashing for the nitrous newbies.... here goes:

Can I run Nitrous on my car?

The quick answer to that is yes. Nitrous can be run on every car known to man. No matter how many cylinders, strokes, or mods you've got done to it, you can run nitrous. Your motor can be 100% stock, you dont even need basic bolt ons. The trick is how to "safely" run it without destroying everything in the process. Mileage is not necissarily a concern, but it is a good indicator of the kind of wear your engine has. Either way, a compression or leak-down test must be run before using nitrous in any fashion. The compression numbers for each cylinder should be within the manufacturers specification. Keep in mind that using nitrous (or any sort of forced induction) will create higher temperatures and cause premature wear of engine components. This doesn't mean your engine is going to blow up after a couple uses... it means more that instead of 300,000 miles out of your Honda motor, you might get more like 200 or 250 before major problems occur. Also, any sort of aftermarket ECU chips or control modules that advance timing are not safe to use with nitrous. Due to the higher oxygen content in the air/fuel mixture when spraying nitrous, advancing the timing can cause predetonation and is what blows up motors.

Types of Nitrous Kits

There are many different ways to inject nitrous into an engine, from dry kits, wet kits, direct port, fogger plates... amongst others. I'm only going to go into the two most common of the systems, as if you you were going to use one of the others, you'd better know your stuff or you'll probably mess something up...

Dry Kits
This is the simplest of the nitrous kits and the easiest to install of them. Dry kits consist of a single nitrous nozzle plumbed into the intake tube about six inches upstream from the throttle body. Extra fuel is provided by the injectors, when the ECU's sensor detects an increase in oxygen. Some kits up the pressure at the fuel pressure regulator by using a nitrous pressure regulator to send a small amount of pressure to the FPR by way of vacuum to increase the pressure accordingly. (NOS is one of these kits). Although a dry kit can be set to produce any amount of horsepower, it is recommended to not jet past 75hp or half of the motor's stock hp, whichever comes first. This is due to the fact that because nitrous is injected through the intake manifold, it is not distributed evenly to the cylinders, while the fuel is being distributed evenly. therefore, some cylinders will see a more rich condition, while some will be more lean. A lean air/fuel mixture is what causes predetonation, and that blows motors. Some dry kits use only one solenoid, others use two.

Wet kits
Wet kits are basically the same as dry kits, except for the fact that while spraying nitrous, they also spray fuel. Wet kits use a fogger nozzle (named as such because it helps to mix the nitrous and fuel together while injecting). The fogger nozzle is mounted in the same place as the dry kit, six inches upstream from the throttle body. These kits use at least two solenoids, one for nitrous and one for fuel. Obviously, they're a little more difficult to install, but not as difficult as one might think. (it really just requires fuel system work and running new return lines and such... plus drilling into places some people are kinda afraid to drill into, in case they mess up). The principle is to rectify the uneven distribution of dry kits. It's still not perfectly even distribution of the mixture (as the fuel is more dense and heavier than the nitrous) but it works a little better than the dry kits to help prevent detonation. think of a wet kit as just added insurance for your motor.

Other types of injection
these include direct port systems and plate systems, amongst a few less standard injection theory kits. these kits are designed to inject nitrous and fuel together, evenly, into each cylinder individually. I wont really go into much detail on these kits, cause they're installation is time consuming and much more work than the previous two... plus, it's a good idea to do some real motorwork with these kits as there's no point in using one of these kits if you just want a light hp increase. A lot of work goes into a kit of such stature, and shouldn't really be discussed here.

What should I do before running nitrous?
This really depends on what size shot you want to run. First you'll need to run a compression test and be sure all your numbers are within spec. Second, familiarize yourself with spark plug heat ranges and also how to read them to determine combustion productivity (i.e. how well your ignition is working on burning the mixture). When you've done all that, now you can start building your nitrous powered motor.

For a 50 shot or less, all you really need is a set of colder plugs (one step colder than stock). On H22 motors, the stock plugs are a six heat range, colder goes up in number, so you'll need a set of 7 heat range. You can keep everything else how it is, including ignition timing.

For 60 shots, again you'll need the colder plugs and you'll want to retard your ignition timing by a degree or two.

For 75 shots, you'll need the colder plugs (you might decide to go two steps colder now), and you'll retard your ignition by three degrees. Any other ignition-oriented mods you can do will be great, like a multiple spark discharge ignition (MSD), new performance plug wires, and a new distributor cap and rotor will all help increase the effectiveness of combustion. A shot of this size will likely blow out the stock clutch very shortly, so look into getting a stronger one designed for the other mods you have (a triple plate clutch is worthless to a virtually stock motor). It is also a good idea to upgrade the fuel pump to a unit that has a flow increase over the stock part. Also, if you find you're running too rich or too lean, pick up an adjustable fuel pressure regulator.

For 100 shots and higher, you'll need to do some serious work to the motor. Forged pistons and rods, along with piston sleeves will be your first step. A performance head gasket should be installed as well. Also a progressive nitrous controller or a dual stage set-up would be ideal, so that you dont overpower the tires and lose traction upon jetting the system.

Purge valves
The point in a purge valve is not to look cool. If you want it for that, you can do a much more simple set up using C02 and get the same results. A purge valve is designed to purge the nitrous line of air, allowing a fresh supply of nitrous to the solenoids when you begin to spray. After purged, there are no delays in injection and no 'gaps' during spray. Purge valves come in a variety of styles, from single line to quad line to l.e.d. lighted. Using hydraulic air hose, you can pretty much mount the purge line to spray anywhere outside of the car to purge to the atmosphere. "stealth" nitrous kits generally choose to purge either down towards the ground under the car, or onto the intake manifold to help it cool a little, as the nitrous purge comes out very cold.

What's with the retarded ignitions?
hahaha, your ignition is retarded! nitrous powered engines will produce more power if the spark occurs later in the combustion cycle. It's proven. A good rule of thumb is to retard the ignition two degrees for every 50hp of nitrous.

What type of fuel should I use?
You should never use anything less than 91 octane fuel when using nitrous. NEVER. the lower the octane number, the more prone the fuel is to predetonation. like I've said before, predetonation is what blows up motors. Octane boosters might be a good idea if you can afford it, just cause the higher the octane, the more power you'll produce with nitrous. If you can find race gas... use it.

Anything else I should know?
Yeah. A lot. But you'll learn as you go really... but for now, know that the higher the pressure in the bottle, the more power you'll get out of it. Most people try to keep their bottle above 900psi. You can use a bottle heater to increase it and keep it steady, as use of the nitrous makes the bottle cold and decreases the pressure in the bottle, therefore decreasing power. Optimal pressure is between 1000-1100 psi. Be careful when using a bottle heater, as incorrectly wired ones have been known to overheat bottles, causing them to explode.

If you really want to get the most out of your nitrous set up and use it safely, invest in both fuel and nitrous pressure gauges, so you know their pressures at all times. Keep an eye on them while spraying so you'll know how well your car is doing with it.

Basic bolt ons like intakes, exhausts, and headers will help the nitrous system produce more effective power. You should look for an exhaust that has piping diameter of over 2.5". 3" is optimal. Same thing for the intake. With the intake, be sure it is the same size diameter as the throttle body for the most effective airflow. Plus, like I said before, any upgrade you can do to the igntion or fuel system will greatly increase the reliability and effectiveness of your nitrous system.


I think that's about it for the beginner's nitrous stuff. I'll write more info later.
 

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Discussion Starter #6
just curious... how come none of the mods ever stickied this?? I mean, this was good stuff, and the board can always use this info...
 

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PreludeClone said:
just curious... how come none of the mods ever stickied this?? I mean, this was good stuff, and the board can always use this info...
b/c i wasn't a mod when i first read it, then i forgot about it. :-|


let me ask, with a dry kit, how important is the jet placement on the intake tubing?
 

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Discussion Starter #12
by jet I assume you mean nozzle?

on a dry kit (or a wet kit, for that matter), when mounting the nozzle into the intake tubing, be sure to point the nozzle's exit path towards the throttle plate. This will allow for the best mixture of the nitrous with the intake air charge.
 

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this might be a dumb question but can spray in between shifts? kind of like giving ur car a Vtec/turbo feeling? just wondering
 

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Good info! :) Let me just point out that wet kits also put your car at risk of puddling, if your engine has EFI. An intake manifold to accept only a dry charge was never designed to see fuel, but a wet kit sprays fuel into it, anyway. As many of you know, fuel must be a vapor to burn, and the best way to vaporize is it to pressurize and atomize it. Well, this atomized fuel, even after it has vaporized, can recondense and collect in odd little corners of the IM that see less flow. Eventually, there is a significant amount of liquid fuel in the intake manifold, just waiting on disaster. Any amount of backfire, excess reversion, or preignition on the intake stroke (even if its just tiny knock) can set off this fuel, even if you are no longer spraying the nitrous fuel mixture. Obviously, this will cause your intake manifold to explode, which is known to be associated with other underhood problems.

For this reason, a direct port setup may actually be the safest way, especially using the new NOS "NOSzle" injector collars. With this method, you are spraying an even, exact, and precisely controlled amount of nitrous and fuel directly into each intake port through the runners, just like the injectors themselves. This is often linked to a progressive nitrous controller, and sometimes a small dry-shot "first-stage" somewhere in the intake tube. The reason this is viewed as dangerous is that it delivers quite a bit of fuel and nitrous into the engine, and the motor must be both built and tuned to handle it. Also, progressive nitrous controllers offer alot more options, and as a result, can kill your motor if tuned improperly.
 
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