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Nitrous Questions..read here first.

83K views 398 replies 120 participants last post by  whmoore18 
#1 ·
I will try to answer a few of the basic nitrous questions we get asked quite often in this section.

First, Nitrous Oxide is a gas which carries an extra oxygen molecule. When extra fuel is added in the presence of nitrous the extra oxygen is stripped off and allows more fuel to be burned, thus increasing cylinder pressure ( much like a turbo, or supercharger ) and therefore making more horsepower, nothing more, nothing less. If these things are done at the right time and , most importantly, in the correct amounts, reliable boosts in power can be had.

NITROUS BASICS

All nitrous systems rely on the stripping off of this extra oxygen to mix with extra fuel to make horsepower. They just do this with different methods. The nitrous is always contained in a High pressure tank, usually around 950 psi, but it can get even higher than this. So, this tank needs to be PROPERLY secured in a safe place, also, nitrous oxide IS NOT flammable, some movies have made this an issue, it has even become a problem in some states to have it in your car. So checking with your local laws is in order. Just a personal note, having your nitrous bottle prominently displayed may look cool, but it may not be such a good idea with local law enforcement.
The fuel is supplied in different ways for different systems and will be explained under each companies header.
There are also several safety devices to help keep things from going wrong, I will explain these at the end, as well as how important I think each one may be.


NOS AND NITROUS EXPRESS ( ALSO FAST & FURIOUS)

I will address these two companies together as they are basically two companies building the same product. Both are wet systems, which means they inject nitrous and fuel together. These systems use electrically powered solenoids to supply both fuel and nitrous from seperate locations, they are mixed together at the nozzle by metering jets.Then this mixture is injected into the intake track AFTER the MAF, through a small nozzle. These jets can be changed to select the desired horsepower levels going to the motor. Also, once you get another car, these kits can be removed and tranfered to another car, just by changing the jets to the proper ones.
The fuel is tapped off the fuel line or can sometimes be pulled from the fuel rail test port ( in carbureated applications a seperate fuel pump may be used ), The nitrous is supplied from a high pressure tank, this is then routed through the solenoids that are electrically activated. There is usually a switch to turn on the whole system, as well as some type of activation switch. This can be a wide open throttle switch ( W.O.T.) that activates when the throttle pedal is depressed to the floor, or it can be a push button switch such as on the top of the shifter, there are other types of safety switches which will be discussed later.
These kits reguire that you have decent mechanical ability and some good electrical wiring skills. Be honest with yourself, if you have any doubts as to your ability to install one of these kits, PLEASE pay a professional to do so.

ZEX

This company uses the throttle position sensor (TPS) to vary pressure at the fuel pressure regulator to raise fuel pressure in the stock injectors to a safe level when injecting nitrous oxide. This is what is considered a dry system as it uses the existing fuel system to meet the needs of the nitrous oxide being injected. This is considered an easier sytem to put together as there aren't as many lines and wires to run and hook-up. This system also keeps an eye on bottle pressure and rpms as part of its system.
Pros and cons of this sytem. It is very easy to install, but several people in the industry are not a fan of " dry" systems as the fuel supply from the stock components can fall short resulting in a lean condition in the motor, which can lead to detonation and eventually breakage of the motor. Personally, I think dry kits are okay for the smallest of horsepower hits, but why not play it safe and install a wet system. I also understand Zex now offers a "wet" system.

JG Edelbrock

I have not seen one of these kits yet, however, they make both wet and dry kits as described above.So in other words they have a kit built like the Zex and they build a kit like the NOS and Nitrous Express. Most parts Edelbrock makes are usually of high quality, so I am sure they build a good kit.

VENOM

This is the kit alot of people in the industry talk about, but few people buy one. Why? the cost of admission. Retail on the kit is $1,500, yes you can find them cheaper on the web, but they are still very expensive. Mosts kits start in the 400- 500 dollar range, so you can see that the venom is quite pricey.
Now to its function. I was checking a system out at a dealer show. It seems to work on the same principals as the Zex kit above, it is just done in a much fancier more digital way. It is a programable sytem with a very fancy compuer lcd display. Once installed it can moniter bottle pressure and whether the exhaust on the car is rich or lean and correct the nitrous mixture to suit your needs, it is also adjustable in its horsepower levels on the fly. This system is capable of being hooked into your laptop as well, so it really appeals to the techno-wizard crowd. This all sounds good, but it makes for what looks like a very advanced , complicated install for the novice, and it still has the possible pitfalls of any " dry" system.

SAFETY DEVICES

There are quite a few of these, they are not mandatory, but several are just a good idea. Some of these do not apply to all nitrous sytems.

1.) Fuel pressure safety switch ( about $40 ): This keeps an eye on the fuel pressure going to the solenoid in a " wet" nitrous application. If the fuel pressure for any reason, drops below a certain amount it will shut the system down and save the motor. It mounts inline to the fuel solenoid.

2.) RPM switches ( about $60 ) : These can be hooked up to the tach. On a focus this requires buying a tach signal generator ( an extra $55, oh joy!), Ford Part # 161-M-17361-A200. What this allows for is the nitrous to only activate between a certain RPM.. A " window" if you will. The advantage of this is that you can shut the nitrous off before you hit the rev. limiter in the car ( I have mine set 600 RPM before for safety). The problem with many modern rev limiters is that they drop half of the cylinders electrically to slow the engine. The nitrous is still being fed to these cylinders, " puddling" in the intake track, since it is not being consumed, then when the cylinders come back in it ignites all this " puddled" nitrous and BOOM ( this has cost several mustangs a new plastic manifold, our foci use plastic manifolds as well.) This device can prevent this..Good thing.

3.) WOT switch ( supplied with most kits $ 5): A wide open throttle switch ( usually mounted on the throttle body, often hard to find a good spot for ) will simply insure that the nitrous is only applied at WOT.

A few pics of switch mounts are here: http://www.focusfanatics.com/forum/showthread.php?t=81204&highlight=picture+WOT+bracket

OTHER NICE THINGS TO HAVE

1.) Remote bottle opener ( $240) : Very pricey, but a must if your nitrous is " hidden" from view.

2.) Bottle Heater ($200) : Not a must, but I wouldn't have a nitrous sytem without one. Basically it keeps the bottle heated to a proper pressure ( 950 psi ), so as you can get a proper horsepower hit from your system. You can lose MORE than 50% of your nitrous h.p. hit due to bottle pressure being to low. This device prevents this.

3.) Fuel rail adapter ( $25): Focus Central makes this little part ( can be homemade as well) that allows you to easily tap the fuel supply for a "wet" sytem off of your fuel rail test port instead of splicing into the fuel line, makes life easier.

4.) Purge kit ( $100) : IMO really not needed on the street except for show ; on the track they serve the purpose of getting all the air out of the nitrous lines so the " hit" is instant and full-on

5.) Nitrous pressure gauge ( $40) : Usually come with kits, nice idea to keep an eye on bottle pressure, there is also a remote in cabin one available.


To sum up, you can do a nitrous system on the cheap and it will probably work fine, but it will work better and will be much safer and more reliable if you spend the extra money on some of the good things. As above, some of these kits are QUITE involved , if you doubt your mechanical abilities at all PLEASE pay a professional to do the install for you.

Also, as some of the pros will notice, I have intentionally left out direct port nitrous installs and nitrous controllers, I know about these and have done several, but I feel these are definately in the realm of the professional and do not belong here in a " how-to" area.

Insert standard if you hurt yourself it is your fault statement here, and please, have fun, but be careful and use some common sense
 
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#127 ·
Second caller, with a 35 or 50 shot, no tuning is necessary, just run premium gas, above this HP level you neeed tuning
Im going with a 25 or 50 shot dry system. Should i get a tune anyway? Just for the sake of doing things right? Or am i wasting money??

Also, i read here about closing the gap on the plugs but i have a screamin demon pack so i have mine open more. What do i need to do about that??

And btw mate, great write up [thumb]
 
#128 ·
I prefer to run a wet shot, as they supply their own fuel... A dry shot can be safe IF, big if. there is enough fuel in the injectors to keep it alive. If you run a dry shot, make sure the AFR is safe when you are spraying. A wet shot is really the better way to go with our cars.
 
#130 ·
Also i read thread affter thread about a bottle warmer. Which i completly understand. But my question is this, and if i missed it somewhere, jus kick me in the nuts,,,but what about summer temps? Like will the heat be too much for bottle psi?

I have sen temp get to 120 degrees in my car in the summer.

Also since i am gonna but using my car for a daily driver, maybe i dont need the NoS tune????
 
#131 ·
I have never had the bottle pressure to high in the summer, the bottle heater gets HOT!...The summer you usually do not need the heater, but don't worry you are safe..

The bottle prressure is 950 std. 1200 is max. The bottle is rated safe to 1800psi, which the blow rating on the bottle is twice that at 3600PSI. and there is a blow pff cap that lets go at 3,000 built into every bottle. I have never seen the bottle in my car above 1050 due to ambient heat.

I run a .055 gap with the screamin demon coil pack and SD wires and have no issues with a 50 shot. The stock coil is also quite good.
 
#132 ·
Man, I thought nitrous was supposed to be cheap. Been lurking on prices, and a basic 4-cylinder direct-port setup from NX is $800, and an extra $400 for the extras not included, like blowoff, fuel cut, NHRA pipe, etc...

Could one piece together parts to save some coin, or are kits usually the better buy?
 
#133 ·
Kits are def. the better buy as the parts are all VERY pricey. Yeah, nitrous CAN be done on the cheap, but to do it right costs $$$$$. I have between 1100 and 1200 in my set up. If you need a remote bottle opener I have a spare one New in the package I can sell you, otherwise I'm using everything else.
 
#134 ·
Hmm. Things keep adding up, even in my wish list.

For the things I'd like to do, it seems I see a lot of suggestions for an inline fuel pump for something like a 100 direct port. Is that really needed on a Focus, and if so, how hard is it?

(I'm sure its been asked before, but this thread got long)
 
#135 ·
Not sure if the stock fuel pump can support that or not. I would guess not.

Its not really that hard, you have to run switched 12v to your new fuel pump and supply it with fuel. We had to do it all the time with carbed motorcycles, so its not terrible, but it is more work. If you call the NX tech guys they can lay the whole procedure out to you, and tell you what you need to buy.

I just thought of it, if you have to put a seperate bung in the tank to pull the fuel, that will be a PITA, but I"ve done that before ,too. But it means dropping the tank and doing it. Call the NX tech guys, they may know, or you could do a small seperate fuel cell as well, and draw from that. That may be easier.
 
#136 ·
Yea, I was wondering how a second pump would work with a factory in-tank pump. Wasn't sure if it needed a second line or not.
 
#138 ·
I know they work well for the guys with blown cobras that up the stock output. If it can be used for a focus ( and it should be ) it may supply enough fuel for a direct port hit. If you run a fuel safety switch ( I recomend it ) you will know if the stock pump falls short. The SVT pump is great, not sure if it works on the dura.
 
#140 ·
That kit is fine to start with. You may want to add a bottle heater, and a fuel pressure switch if that kit doesn't come with one... Jet it one fuel jet size rich on the fuel, and start at the 55HP hit. Also go a step colder on the plugs. I don't have any experience spraying an svt, but you may need a tune as well if you want to go to a 75 shot. The SVT seems to be a bit pickier on the tune than the regular zetec.
I would contact Tom at focus-power.com about the need for a tune for your svt.
Any questions just ask.
 
#141 ·
Well do u know of a kit that comes with fuel pressure switch ,?

Jet it one fuel jet size rich on the fuel
How do i go about doing that?

I dont wanna go over a 50 shot, anyhow. Just wanna add a little without having to do alot to the motor.

So on the wet system i will need to somehow tie my fuel into the NoS nozzle so they mix togther and spray after my maf. Is this correct?

Also where can i get the fuel to mix with the nos? COme off my current fuel rail somehow?
 
#142 ·
When you get the nitrous kit, it will explain all this in the directions. NX and NOS are very good. But the fuel can be tapped off the end of the fuel rail with an adaptor...Several of our vendors keep them in stock ( try Mcnewsautomotive.com )
The nitrous flow and the fuel flow ( which control the HP ) are controlled by jets that you can change with different sizes. One size larger on the fuel jet makes a slightly less powerful hit, but it is safer on the focus.
When you get the nozzle you will see how it mixxes, the fuel at about 40psi shoots in and the nitrous at 950 psi shoots through the fuel, it does a pretty good job of atomizing it.
YES, after the MAF.
 
#144 ·
FYI, the 100shot is possible using a wet kit and the stock fuel pump. I'd go with a +1 higher size fuel jet on the 100 shot though. For a direct port setup I'd definitely have a tune made for 100 shot and find rods/pistons for sale. You're going to need them after one screw up.

Keep it safe and you should be fine!
 
#146 ·
I read the entire sticky on nitrous and tried to IM Sublime per your advice. Unfortunatley, he has chosen not to receive them.


Soo, what are your thoughts towards an 06 automatic and a 35-50 HP shot of nitrous? I read an article from Muscle Mustangs and Fast Fords where they added a bottle and suffered tranny problems. The computer couldnt decide which gear to put the car in after the run.
 
#147 ·
I have a NX kit on my SVT and was curious to see what everyone was setting their Window switches to. I have mine at 3500-6500.
I was thinking of putting it to 3000 to 6800. To start spraying a little longer.
My next question would be if I set it to 6800, should I shift at 6800 or take it to 7200.
 
#148 ·
unless you have a raised rev limiter(as in, tune), 7200 is a deadly place to go with the window switch, it wouldn't be a good thing for the stock rev limiter to kick in at the same time at the window switch kicks off, no time for the intake to clear...

I run mine on at 4000 and off at 7000, but I have my rev limiter set to 7600, so there is plenty of room .

3000 rpm is a little low to start off... most guys launch at higher rpm's than that, but you can play around with it and see what works best for you. I would recomend not going any lower than that.

If you set it at 6800, you need to shift at 6700 or so... there is no point driving thru the off cycle, its only there for your engine's protection.
 
#151 ·
I agree, set your nitrous cut off at least 400 rpms before your rev limiter, more is better, basically you can set it where the car stops making good power, or a few hundred RPM after that.
I start mine at 3,000, but I am on a zetec and the svt's are a bit peakier.

The auto tranny idea??? Not sure, I know my nitrous set-ups, but know almost nothing about the auto on the focus...I have seen several Ford trucks even have major tranny problems from running larger tires as the computer has issues. For that you would need someone that knows these trannies well, I think sublime has done his research on that more than I have.
 
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