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Premium Member
2,994 Posts
Discussion Starter #2 (Edited)
Dummies guide to nitrous

To make an engine produce more power, you need to make the combustion process more powerful. A nitrous oxide molecule is made up of 2 atoms of nitrogen and 1 atom of oxygen. By weight it is 36% oxygen and 64% nitrogen (air is only 23.6% oxygen).

So when nitrous is injected into the inlet manifold, as more oxygen is present, this allows more fuel to burn. also the nitrogen has the beneficial effect of reducing the temperature of the inlet charge, We all know cooler air is more dense which means more air in the same space therefore.... MORE power:devil:

All this increases the combustion process, and raises the force exerted on the pistons and this means more power..... Mmmm nice:cool:

There are a few different types of nitrous systems

1. dry (only injects nitrous)

2. wet (injects nitrous & additional fuel)

3. direct port (each port has a dedicated injection point, i.e a 4 cylinder engine would have 4, one on each port)

4.single point (as the name implies there is a single injection point before the inlet manifold branches off)

Basically you have a supply cylinder containing nitrous oxide (normally in the boot of the car) connected by a tube to a normally closed electric solenoid valve.
This solenoid valve is mounted in the engine bay in a cool area, and also as close to the point of injection as possible.
This is turned on by a micro switch at full throttle, The fuel solenoid valve receives fuel from tapping into the fuel supply line, this solenoid is also activated by the same micro switch.

The nitrous oxide and additional fuel (in the case of a wet system) is delivered to the inlet manifold through the injectors.
The amount of nitrous oxide and fuel is metered by the jets that are installed in the solenoid outlet fittings (unlike the systems made by nos, NX, etc etc. They put the jets at the injector..... the wrong place:()

Trevor langfield (wizards of nos) was the first to jet at the solenoids, and it results in a softer hitting system. unlike the hard hitting systems from nos, NX, etc.
A softer hit means less strain is put on the engine, and therefore more power can be added.
Mmmm thats what I'm talking about :devil:

OK so i know what your thinking..... nitrous oxide will blow my engine up:eek: or make a panel under the dash explode and fall down with sparks flying everywhere, like on the fast and the furious........ WRONG:screwloose:
That film has so many problems:forehead: like the fact they made a big thing about activating the nitrous almost at the end of the race:eek:
whats the point in that? you activate it straight off the line, or when you have enough traction to put the extra power down.... don't believe everything you see in the movies:rofl:

Its things like this that have given nitrous a bad name:( but Its mainly from people who have used badly designed systems that have caused engine failure, used far more nitrous than an engine can handle, operator error, or just simply the fact that their engine was in bad shape in the first place and would have blown up anyway..... without the nitrous.

Is nitrous illegal to use?
It is perfectly legal to use on a public highway in the UK:cool:
its only illegal if you don't declare it to your insurance company, or you exceed the speed limit...:nonono:
I think there are certain country's that it is illegal to use:( so its best to find out before you buy a kit.... or just move to the UK:rolleyes:

Can i fit a kit myself?
IMO if you are mechanically minded, have a basic understanding of engines then i don't see any reason why not.
But if you don't know the difference between a left-handed screwdriver, and a glass hammer.... better have it done professionally:d

Can i add nitrous to a diesel engine?
yes you can, and as diesel engines are stronger by design, you can get more gains out of them:cool:

Should i use a wet kit or a dry kit?
if you are adding nitrous to a petrol engine, then i would only advise to use a wet kit.
some company's market dry kits to be used on petrol engines that try to fool the engine management into adding more fuel... but i wouldn't do this myself:crazy:

If you are adding nitrous to a diesel then you will need a dry kit. you cannot inject additional diesel or you will be in big big trouble:(

Direct port or single point?
All depends on the manifold design TBH, if the nitrous/fuel mixture has to travel up wards at any point, then it is best to fit a direct port kit.
also if you are only running a relatively small shot, the fuel will distribute more easily than if you are running a bigger shot which contains more fuel, direct port will help distribute the mixture more evenly.
If you are running throttle bodies you will have to go direct port.

How much nitrous can i add?
Theres no hard and fast rule for this, it all depends on the engine.
some engines can handle allot of nitrous, where others find it hard to stay in one piece without any at all:(
Roughly speaking you can safely add a shot of nitrous around 20-30% of the engines original bhp without having to retard the ignition, or use a progressive controller.
I successfully added a 25bhp shot to a standard 1.2 Clio(60bhp D7f engine) which is almost 50% extra bhp, and i had no problems.
The only mods i made to the engine was a colder set of plugs:d

Can i add nitrous to a standard engine?
Yes, you don't need a heavily modified engine to run nitrous, unless you are adding large amounts:devil:
only things you need to do, is make sure the engine is in good condition, and also the fuel and ignition system is up to the job.

How long does nitrous last?
Erm.... not long enough:d

what brand kit do you recommend i buy?
Well TBH theres only one company i would advise on using, and they are the Wizards of nos They are just about the only nitrous company who cares about what they are selling.
Most American kits from NOS, NX, eidelbrook, cold fusion etc etc... the list goes on:crazy: they are pretty much all the same.
They might look nice, but thats about as good as it gets.
Most of them use cheap generic solenoids that are prone to failing and leaking.. especially when pulsed.
They jet at the injector, and as i said before... it results in a harder hit, putting more strain on the engine and transmission parts which is not good!!!
also due to the fact the nitrous is under higher pressures than the fuel, the nitrous will arrive before the fuel does, this leaning out can cause intake backfires which is really not good:(
Also, if your running a direct port system jetted at the injector, there will be 8 jets to change (on a 4 cylinder engine) opposed to just two with a won kit.
they use braided line, which is needed if your running over a 150bhp shot, but if your only running a small amount you will have to wait ages for the liquid nitrous to arrive at the solenoid so you will need a purge kit.
i could go on for ages about this:eek: but anyone who knows a thing or two about nitrous will tell you the same... if they don't, then they obviously don't know much:d

Premium Member
2,994 Posts
Discussion Starter #3 (Edited)
Things to do before fitting a kit

Engine condition
The first thing you want to do, is find out if the engine is in good working order.
The best way of finding this out is by having a "leak down test" done, this will show up any problem's like worn rings, valves, head gasket etc.
when carried out, there should be no more than 6% leakage from any cylinder.
A compression test can be done, but this will not be as useful as a leak down test, as the compression test will show a problem... but will not be as good at finding the cause.
with a compression test, cylinders must not vary any more than 10psi, and must be within manufacturers specs.
if there is a problem, it must be fixed before fitting nitrous.

Its wise to give the engine a good service: oil, filters, etc.

Ignition system
as nitrous will put a higher demand on the ignition system, it will have to be up to the job.
you can test the ignition with a tester like This if its in good condition you should be OK:cool:
If the leads have seen better days get them changed for some decent quality leads.
Its also wise to fit a new set of plugs, and if your going for more than a 25bhp shot, its wise to change the plugs for a grade cooler than standard, this will help to prevent detonation.

Fuel system
the fuel system will have to be up to the job of providing the additional fuel, on relatively small shots the standard fuel system should cope.
but when you start adding large amounts, then the pump will need to be upgraded to a higher flowing pump, or another separate pump and regulator will be required, just for the nitrous system.
ill show how to test the fuel system later on:cool:

Its also a good idea to change the fuel filter.

Premium Member
2,994 Posts
Discussion Starter #4 (Edited)
Bottle mounting

If you buy a kit that is made outside the UK, the main problem you might face is actually having it refilled.
Many of the U.S kits do not have the PI mark on there bottles, this pi mark is required in the uk if you want to have your bottle refilled legaly.... fine if you refill your bottle at home from a rented cylinder, or you know someone who will do it who turns a blind eye.
And if you try to get refills by courier, they will send it back to you.... but it will be empty I'm afraid:(

One place nitrous company's like to save money, is actually on the valve in the bottle.
I have seen many that are just a cheap standard Co2/mixed gas valves, just like the one i used on the bottle for my Clio, but they have chromed it to look a bit nicer.
This is OK, but they will not flow as much:(
I used one because it was cheap, and i was on a tight budget.... did i mention it was cheap:d
Anyway heres the bottle i used in the Clio, it was previously a CO2 bottle that was used in a pub:rofl:

Another thing they like to use is a rupture disk.....
Lets say its a really hot day, and the bottle is exposed to direct sunlight, and the nitrous pressure builds up in the bottle to dangerously high levels.
Or even worse, it has a bottle warmer wrapped round it which fails to switch off after it has reached optimum temperature:eek:
Well... instead of the bottle blowing up, the rupture disk blows out venting 'ALL' your expensive gas to atmosphere:crying:

Here is a maxiflow valve from wizards of nos

  • High flow low friction seat

  • Minimal expansion chamber

  • Low friction coated internals to minimize wear and consequential system contamination
  • overlapped hand wheel and body
The little anodized red valve on the side is a S.P.R.V (safety pressure release valve)
This replaces the conventional rupture disk.
Using the same scenario above with the bottle over heating, instead of blowing out like a rupture disk, it just safely releases a little nitrous at a time to bring the bottle pressure back down to safe levels:cool:
No more loosing all your gas in one go, and no replacing disks either:d

Heres a couple of vids

sprv vs standard rupture disk

Valve drop test

Hmmmmm.... i know wich one i would rather have:cool:


The best place for the bottle to be mounted is close to the solenoids, to keep pipe runs short.
In most cases this is not possible, so tho boot will have to do:d

The bottle needs to be mounted at an angle (about 15 degrees is best) with the outlet facing down, as shown in the pic.
This is because the dip tube inside has to be able to pick up liquid nitrous, this is very important!

The bottle obviously needs to be fixed down securely with bolts and washers, its also good practice to use a thread-locking compound too.

After deciding where the bottle will go (i chose the passenger side on the Clio, as the solenoids would be on the same side up front) first thing to do is check there is nothing in the way underneath that the drill could pass through and damage, like pipes, wires, etc.

Naa.. just a rusty pea shooter under here lol.

Next, mark out the holes where you want to drill.

When the holes are drilled, paint over the bear metal to prevent rust, and also use a little silicone sealant to prevent any water getting in, the sealant also holds the washers in place till the nuts are fitted, which is a bonus:cool:

To make the holes in the carpet i found it best to use a wood drill bit, with the drill in reverse and a block of wood underneath.

When i tried to fit the bottle in the corsa, i had to make a false floor, as there was a wheel well which prevented me from bolting the bottle down to the boot floor.
So i just used the boot carpet as a template, and made the false floor out of some MDF.
I made sure it was a tight fit, so it wouldn't move about.

I just used some T-nuts underneath for the bolts fix in.

The only way the bottle would fit in the boot was diagonally, this is not perfect, but the only way i could get it to fit in there.
i also had to use a block to raise the front up higher, just so it would fit.

The main thing to remember when mounting the bottle, is that the dip tube will be able to pick up liquid nitrous under hard acceleration, and that it is mounted securely.

Premium Member
2,994 Posts
Discussion Starter #5 (Edited)
Solenoid/pulsoid instillation

The solenoids, or pulsoids (in the case of Wizards of nos)
are basically a "normally closed valve"
when they are energized, the electro magnet inside moves the plunger off its seat, by doing this.. the nitrous or fuel (depending on the solenoid) is allowed to flow through.
When they are not energized, the plunger is held on the seat by a small spring and the pressure of the nitrous/fuel.
If there is too much pressure, they actually wont be able to open at all.

These are typical generic solenoids, as used by many nitrous company's.
Normally, the only difference between brands, is a different sticker.
The only reason i used these on my Clio was because they were cheap.... and i wasn't bothered if they failed and blew my engine up:rofl:

The main problem with this kind of solenoid is the seat material, dynotune actually recommends the seals are inspected and replaced regularly.... why make a decent seal that doesn't fail, when you can earn more money selling replacement seals $$$:crazy:
Another problem is the treacherous route the nitrous/fuel has to travel to get through these solenoids, its not exactly a smooth ride.

original source: wizards of nos

Generic solenoid

WON pulsoid

You shouldn't energize this type of solenoid for too long, because it will burn the coil out, and as for trying to pulse them with a progressive controller..... don't expect them to last long:rofl:

These are the pulsoids from wizards of nos, as the name suggests... they are designed to be pulsed.

For a start, they are designed to never wear out... won say that the seals actually look better after they have been used:cool:
The flow path inside is allot smother than the generic solenoids, which means greater flow and more performance:devil:
You don't have to worry how long they are energized for either, you can keep them going till you've run out of gas.... Thats if you can find a long enough road :evil:
You only have to look at them to see they are made to a higher standard than anything else out there...:cool:


The solenoids need to be mounted in a cool area in the engine bay, also the pipe length to the injector must be kept as short as possible, no more than 12" for best performance.
On the corsa i was able to mount them under the scuttle panel, this is one of the best places, as it is shielded from the heat of the engine.
If the solenoids are mounted in a hot area, the liquid nitrous will turn gaseous, you want the nitrous to stay in liquid form as long as possible to get the most out of it.

I was lucky as there was already bracket there holding a fuse box in place, which only had one fuse in the whole box:d
So i just removed the box, flipped the bracket round and mounted the pulsoids to it:cool:

On the Clio i had to mount them in the engine bay, next to the injectors. I also rigged up a cold air feed (the pipe to the right of the solenoids) to help keep them cool.

I wasn't as lucky with this one tho, i had to make a bracket up for them to fix too:(

The worst place to mount solenoids is behind the engine, as this is an area where heat will build up, and get very hot!
If you have no option but to mount them in a hot area, try to shield them from the heat.

Premium Member
2,994 Posts
Discussion Starter #6 (Edited)
Single point injector mounting

The injectors have the job of combining the nitrous and the fuel as its injected into the inlet manifold.
A good setup should have the nitrous 'atomize' the fuel into a fine mist.

There are two different types of injectors out there, one of them has a two separate injectors for the nitrous and fuel.
The nitrous is situated behind the fuel injector so it can collect the fuel and atomize it, like this...

I actual made these myself out of some pneumatic fittings.
the nitrous jet is just a fitting that has had a small piece of copper tube soldered into it, the copper tube has had the end soldered up and a hole drilled in the side:d
The fuel jet is just a standard unmodified fitting.

The one at the back is for the nitrous, and the one at the front is for the fuel, so as the nitrous is sprayed out, the fuel is collected by the nitrous and atomized.

Here's a little vid, if you look closely you can see the fuel entering the nitrous plume:cool:

The other type is a combined injector like this

This is the 'crossfire' injector from won, the little hole in the middle is where the fuel exits, and the two holes either side are where the nitrous exits in a crisscross pattern, effectively collecting and carrying the fuel as it exits:cool:

Heres a vid

The reason the fuel comes out first is because I'm running a progressive controller, i had it set up so theres a slight delay for the nitrous. you can also see that is is being pulsed too:cool:

Many other nitrous company's use combined injectors (fogger nozzles) too, but many of them have a large expansion chamber inside... This is not great for best flow and performance:(
Some also have a very narrow plume, this doesn't lead to good distribution on a single point setup.
They also fit the jets in the injectors..... not good:crazy:
more on that later......


As i mentioned before, some manifolds will not do well with a single injector setup, if the mixture cannot distribute evenly between cylinders, you will get big problems.
If the mixture is not equal for each cylinder, some will be getting more fuel, where others are running lean:(
Its mainly manifolds that travel up wards after the point of injection that have problems with single point setups, as the fuel will be less likely to distribute evenly in this type of manifold, or even worse the fuel can puddle in a dip or bottom of the manifold, which can lead to problems such as inlet manifold backfires:eek:
In this case it is best to go direct port.

The injector must be mounted as close to the throttle body as possible, its usually possible to mount it in the rubber intake tube, i usually use a wood drill bit for this.

Mount the injector at about a 15 degree angle to the pipe, this will help the mixture swirl and distribute more easily:d

Premium Member
2,994 Posts
Discussion Starter #7 (Edited)
Direct port instillation

As i mentioned before, a direct port setup is best when using a large shot of nitrous, or when the manifold doesn't work well with a single point setup.
And if you are running throttle bodies.... you cant get away from it:devil:

Its basically the same as a single point setup apart from each cylinder has its own injector, so a 4 cylinder engine would have 4 injectors, and a 6 cylinder engine would have 6, and so on.
On a basic 4 cylinder setup, a distribution block is used to distribute the nitrous and fuel to the 4 injectors.
With many American kits, they use badly designed distribution blocks that do not distribute the nitrous/fuel evenly.
You can see in this video (about halfway through) how the majority of the nitrous goes to the top two outlets of the block.

Original source:

Generic direct port kit (purged)

Direct port instillation

If installing a distribution block from won, it is best to have it mounted upright, so the inlets are vertical.
This will ensure even distribution to all injectors.

Installing the injector is a little more tricky, because you will need to drill and tap a thread into the inlet manifold.
It is best to do this with the manifold taken off the car, just in case any swarf from drilling enters the engine.
Its also wise to use locktite on the threads, to stop them coming out.

The location of the injectors in the inlet runners needs a bit more thought too, this is mainly due to reversion.

What is reversion?
As the inlet valves remain closed for the majority of the otto cycle, this will mean that nitrous will be spraying down the inlet runner at a closed valve for most of the time, if the injector is mounted too close, the nitrous can bounce off the valve.... this is reversion.
This is not such a problem when using a single point system, or a small shot on a DP system.
But when a large shot is used it can become a problem.

So its best to mount the injector as far away from the valve as possible to prevent reversion.

Here is a setup on an MR2 using venom injectors, as you can see the distribution block is mounted upright, and the nitrous injector is mounted as far back as possible.

Original photo from NITROUS OXIDE ( nos / n2o ) advice forum

Here's a Peugeot 205 running Yamaha R1 bike carbs, this is using the crossfire injectors.
As the carbs do not allow the injector to be mounted too far away from the valve, this is the only option.

Original photo from NITROUS OXIDE ( nos / n2o ) advice forum

Also when plumbing the injectors, keep the pipe lengths equal to ensure correct distribution.

link to photos: Noswizard

Premium Member
2,994 Posts
Discussion Starter #8 (Edited)
Switches & wiring

Arming switch

Find a suitable place to mount the arming switch, somewhere in easy reach is a good idea:d

Before you go drilling holes, obviously make sure there is nothing behind that will be damaged by the drill.

Heres the switches i used on the corsa, the one on the left is for a purge kit.

Throttle switch

As you only want to activate the nitrous at full throttle, you will need a switch that will be activated, only when the throttle is fully open.
theres a couple of ways to go about this, the cheapest way is to fit a micro switch on either the throttle body linkage, or on somewhere on the foot pedal linkage.
alternatively WON sell a TPS activation switch that is allot easier to install than the micro switch, this can be found here

On both the Clio and the corsa, i used a micro switch mounted on the throttle body.

Throttle closed

Throttle open

just make sure that the switch is only activated, when your foot is fully on the accelerator pedal, and it doesn't get jammed or stuck, this is very important!!

Heres the one on the corsa

simple stuff really:cool:


Wiring is fairly straight forward TBH when using wiring and switches from WON.
If you can find a suitable switched live (only live with ignition in position II) that will not be used when the nitrous system is activated, and is capable of supplying the solenoids, then you can wire up like in the following diagram.
If using different switches, they must be rated for at least 12 amps, otherwise a relay must be used.

I prefer to run a live from the battery and use a relay as shown in the following diagram, this is the safest way TBH.

Use a test meter to find the switched live, it is important that this wire is only live when the ignition is in position II.
Try to find the biggest wire you can, then solder a spur wire on and insulate the join, this will be the +12v (ign)

When finding places to mount the relay, have a look in the fuse box as there might be a spare place that isn't being used:cool:

Just remember when running any wires, make sure all connections are insulated and secure, and the wire will not chafe on bare metal etc.
Use cable ties to tidy things up, and if you drill a hole for the wire to pass through, use a grommet.


Premium Member
2,994 Posts
Discussion Starter #9 (Edited)
N2O supply plumbing

All of the American kits are supplied with braided line, this is OK if you are going to be using a shot over 150 bhp, but it isn't the best if you are only running a small shot, as the line will take a long time to fill and will need to be purged.
nylon line supplied by won is much better if running up to 125-150bhp and doesn't need to be purged.

Theres allot of argument's about which best to use, heres a link that might help you decide for yourself:cool:

N2O plumbing

When routing the supply pipe, try to take the shortest route possible, also make sure the line doesn't get close to any sources of heat, as this will cause the liquid nitrous to turn gaseous which will cause loss in performance.
Try not to kink the pipe, as this can weaken it, and its also a good idea to leave a little extra pipe the bottle end, then you will be able to cut the pipe down a little bit if you ever need to change the nut and olive for a new one.

The best place to run the pipe is underneath the plastic trim inside the car.

On the corsa, I used p clips to hold the pipe in place under the trim.
On the Clio there were clips already under the trim, so i just used them.

Just make sure when the trim is replaced it doesn't crush the pipe!
The pipe can now be run under the dash to the engine bay.

You will probably need to drill a hole through the bulkhead to get the pipe through, if you do... don't forget to use a grommet to stop the pipe getting damaged.

If the solenoids are mounted in the front of the engine bay, its better if the pipe is run behind the wing as this will be cooler.
this is what i did on the Clio, i covered the pipe with convoluted tube to help protect it.

The nylon pipe is connected to the bottle and solenoid using a nut and olive fitting, use Stanley knife with a new blade to make a clean cut, then slide the nut onto the pipe and then the olive.
Do not over tighten the nut, as this will crush the pipe and reduce flow, you should tighten the pipe enough so it will not come out when pulled on hard.

Connect the pipe to the bottle first, and secure the other end of the pipe so it wont move about, then just open the valve for a second to clear the pipe through before it is connected to the solenoid, this will blow any crud out of the pipe.

Then the pipe can be connected to the solenoid using a nut and olive.
Don't forget the pipe has to go into the inlet of the solenoid... not the outlet!

when you have connected the pipe up, open the bottle valve and check for leaks, use some washing up liquid diluted in water, and just put a little around all connections. If there are any leaks you will be able to see bubbles, if they are leaking tighten the connection up a little and check again.

As you can see, this connection is leaking.

Premium Member
2,994 Posts
Discussion Starter #10 (Edited)
Fuel take-off and plumbing

To supply the extra fuel, you will need to tap into the fuel supply line before the fuel pressure regulator.
it is very important that you locate the correct pipe!
A good way of checking, will be to find the fuel line that runs from the fuel filter to the fuel rail.

Theres a couple of ways to do this, you can either tap into the feed pipe with a t-piece as in the diagram above.
Alternatively.... if your fuel system has a fuel pressure test port, Won sell adapters that will convert it to accept a nylon line:cool:

Fuel is highly flammable, make sure the fuel system has been depressurized before you start any work on the fuel system.
you can do this by removing the fuse for the fuel pump, and then trying to start the car.
There will still be some fuel in the pipe's, so just be careful!

Fitting a T-piece

When you have found the correct fuel line to use, find a suitable place to cut the pipe, preferably as close as possible to the fuel solenoid.

Make sure you use proper fuel hose clamps, do not use the typical worm drive hose clamps, as these can leak!

Then connect the hose that will run to the solenoid.
This is a typical T-piece that you will get with an American kit.

The T-piece from won will allow you to connect a 4mm nylon line into it, opposed to using a bulky rubber hose as above.

Original photo from NITROUS OXIDE ( nos / n2o ) advice forum

Shrader valve adapter

If your car has a fuel pressure test port on the fuel rail, you can get an adapter from WON:cool: this is much easier than messing about and cutting pipes:d

Here is the test port on the engine in my corsa.

Won supply a tool that will enable you to remove the valve core... THIS IS VERY IMPORTANT!!

Very carefully depressurize the fuel system, start to screw the tool into the valve with the tissue wrapped round to stop any fuel spraying anywhere.
The fuel will be under very high pressure, so be careful!!!!!

With the fuel system depressurized, you can use the tool to remove the valve core.

Valve core removed.

Them the adapter can be screwed onto the valve, remember to use the sealing washer supplied. (very important!)

Now you have a fuel take-off:cool: simple stuff eh:d
The nylon line can now be connected using a nut & olive, run the line to the fuel solenoid, making sure to keep away from sources of heat.
Use cable ties to hold the pipe in place, and if passing through a hole... use a grommet!

When all connected up, don't forget to check for leaks!!!!

Link to photo Noswizard

Premium Member
2,994 Posts
Discussion Starter #11

The purpose of the jets is to regulate the flow of the nitrous and fuel.
Most American kits have the jets fitted at the injector, but WON fit the jets at the solenoid.

There are many reasons the jets are located at the solenoid with WON systems, there is a good explanation HERE

Here are the jets from won, they are just screwed into the outlet fitting of the solenoid/pulsoid.

The jet is basically a screw, with a hole drilled through it, and the size of the hole determines how much fuel/nitrous is able to flow through.... simple eh:d

Without jets

With jets

Typically on a fuel injected car the fuel jet is half the size of the nitrous jet.
E.G. for a 25bhp shot the fuel jet would be 25 and the nitrous would be 50, i say 'typically' because there are a few things to take into consideration like fuel pressure, distribution, and the pressure of the nitrous (due to the fact, nitrous pressure is directly related to temperature)

So in my case with the corsa, i have 100 size jet for the nitrous, and a 40 size jet for the fuel to get a 50bhp shot.
It is best to speak to won when ordering jets!

The jets from won also have a number stamped on the side so you don't get them mixed up.

When i did the Clio, i actually made and drilled the jets myself :eek::rofl:
I wouldn't advise doing this with the jets from WON tho!

you really need to know how to do this:rolleyes::d

just do one at a time so not to mix them up, and don't over-tighten them:cool::d

Premium Member
2,994 Posts
Discussion Starter #12 (Edited)
Injector plumbing

Use the 4mm nylon line to plumb the solenoids to the injector, using a nut and olive.
red for fuel, blue for nitrous.

with the corsa i had to pass the lines through the bulkhead, so i just used some large grommets to stop the pipe chaffing.

With the crossfire injector, it is important which line goes where into the injector.
the fuel line goes into the fitting that has two dimples, and the nitrous into the other, this is very important!

just remember not to over tighten the fittings, and to try to rout the pipe away from sources of heat.

Premium Member
2,994 Posts
Discussion Starter #13 (Edited)
System testing

First test to do is to make sure that the nitrous and fuel are getting to the injector.

Turn off the nitrous valve and remove the injector, hold the injector in some old rag to collect the fuel.
With the engine running, arm the system and operate the micro-switch, and see if fuel is flowing out of the injector.
If there is no flow you have a problem! Do not operate the nitrous system without any fuel!!!
check the solenoid is wired up correctly, and the jet is not blocked etc..

If you have fuel, all is well:d


Disconnect the earth from just the fuel solenoid (as you do not want the fuel to come out in this test!)
You do not need the engine running in this test.
Turn on the bottle valve, now hold the injector Wearing a thick glove!! and point the outlet away from the body,
Then... with the system armed, activate the micro-switch.

you should have nitrous come out of the injector, if not... check you have undone the valve, and that you have any nitrous in the bottle:d
And check the solenoid is wired up correctly.

If you have nitrous coming out of the injector.... all is well:devil:

Fuel system test
To check that the fuel system can cope with the extra work, you will NEED to do this test!
If you don't.. and the fuel system cannot cope supplying the extra fuel, your engine will run too lean.
This will probably result in major engine failure:(

Disconnect the nitrous solenoid and turn off the valve, then undo the nylon fuel line at the injector end.

Replace the jet in the fuel solenoid for a size slightly larger than what will normally be used.

It is also a good idea to set up a fuel pressure gauge, to monitor any pressure drop.

Now find a small plastic drinks bottle, and secure the line from the fuel solenoid into the bottle.

now with the engine running, activate the fuel solenoid for a period of about 10 seconds (this must be timed, not just a guess)
now remove the bottle and mark the amount of fuel collected on the side of it.

if you had a pressure gauge fitted take note of any pressure drop when the system is activated (there should be very little)

Now empty the fuel out of the bottle, and secure it under the bonnet so it will not move about.

Now its time to repeat the test, but this time under full load conditions on the road.
eg, accelerate at full throttle from 3000rpm in third gear with the system activated for exactly the same time as the first test.
And also take note of any pressure drop, there should be NO more than 4psi !

Now remove the bottle and check how much fuel has been collected, there should be the same amount as before, or more.

If there is less, then the fuel system will not be able to supply the additional fuel and another supply will be required.

Just remember that this test will need to be done again if you change the jets to a larger size than you have tested for.

Static test & road test

link here

Static test pro mod vid

Big power static test pro mod (don't try this at home:rofl:)


Premium Member
2,994 Posts
Discussion Starter #14 (Edited)
Progressive control

with a fixed hit system, the solenoids are either open or closed, or put simply the system is either on or off:d
This is OK if using a small shot, but if you want to add more power you will have to be able to progress the nitrous delivery.

Staged systems
In the early days people used to use staged systems, this would consist of two or more fixed hit systems, so basically a two stage system would have two sets of solenoids and injectors.
For example, the first stage would be jetted for a 25bhp shot, and would be activated first.
then the next stage would be a 50 bhp shot that would be activated next (but the first 25bhp system would deactivate)
Then the next stage would be both systems activated together resulting with a 75bhp shot.
This is a crude way of progressing nitrous delivery TBH, and it requires another set of solenoids, lines, injectors, wiring etc.

Pulsed systems
The most common way of progressing the delivery today is by pulsing the solenoids, this is done by using an electronic controller to pulse (open and close) the solenoids..... or should i say pulsoids:d

Here are the pulsoids in action on my corsa:cool:

And the maximiser controller from WON

More info for the maximiser and fitting instructions HERE

Smooth progressive system (REVO)
Won have now developed a smooth progressive system,
Its not available to the general public at the moment, but will be soon.
instead of pulsing the solenoids, they are opened like a tap, this has many benefits over pulsed systems.
more info HERE

Here's the first 'simple' video of a pair of REVO valves being operated by a Max Extreme.

To show the flow is linked to the Revo movement, we've added a position indicated to each drive shaft.

We also flowed nitrous through both Revo valves (rather than nitrous and fuel), for the following reasons;
1) It's safer
2) It's more obvious to see the changes in flow

You'll notice that the indicators and flow through each Revo is different and the reason for that is to demonstrate the mixture control that the Max Extreme provides.

Both Revo valves could be set to deliver equal flow but this demonstration shows how the mixture can be adjusted to optimum.
revo vid

The following clip demonstrates the range of control that the Max Extreme offers over the Revo flow and shows how advantageous the combination will be over ALL existing nitrous control systems.

For this clip we set the Max to deliver 3 different flow rate ramps in 3 different gears. We added a break between each gear to define the change in gear but the Max can be set so the delivery continues to rise or drops to any level before rising again without any breaks, if required.

In these examples we set the 1st gear to start from zero and rise to 100% then switch off quickly, in the next gear it was set to rise to 100% immediately and then reduce flow slowly and in the 3rd gear it was set to rise from zero to 100 and back again evenly.

The possibilities (as the recycling advert says) are endless.

Click to watch revo gears

Now is there still anyone out there who doesn't grasp that this is the most advanced nitrous technology in the world????????

The next time anyone sees the likes of Speedtech, NX, NOS, Ny-Trex, etc. etc. claim that they have the most advanced nitrous products/technology in the world, just have a good laugh for me, because none of them would know advanced nitrous technology even if it smacked them in the face.

First production revo test

Premium Member
2,994 Posts
Discussion Starter #15 (Edited)
Nitrous do's and donts

Items without an * should be carried out before using the system. Items marked
with an * may apply to power increases above 25 bhp and items marked with a **
should apply to increases above 50 bhp. These are just general guidelines to
follow and can vary per application.

Do replace the existing distributor cap and rotor arm if applicable.

Do have your fuel system tested to make sure wanted power can be supported.

Do replace the existing spark plugs with one grade colder (harder).*

Do fit a set of quality plug wires (leads) if applicable.

Do fit a high capacity fuel pump.**

Do have your engine compression checked with a leakage tester (not a compression
gauge). 6% is just acceptable, but no cylinder should exceed a 10% leakage.

Do fit a high performance ignition coil and ignition system if applicable.**

Do retard your ignition timing 2 degrees for every 50 bhp.**

Do check torque settings of head bolts.

Do use only top quality oil. **

Do use high octane fuel (petrol) and even higher octane for power increases over 50%.**

Do purge the nitrous system at night or when the vehicle is left unattended.

Do fit an Ignition Delay Unit (IDU) or an ignition kill switch to prevent the possibility of
backfires that may be caused when starting an engine with a static nitrous charge in the

Do not operate the nitrous system without the engine running at a suitable rpm in an
appropriate gear.

Do not start the engine if you suspect the nitrous system has been activated while the engine
was not running. Purge the nitrous from the engine by removing the plug caps and cranking
the engine over, or fit an Ignition Delay Unit.

Do not use the nitrous system when the engine is off load other than for brief testing
during a static test.

Do not leave the nitrous bottle valve open while the engine is not running.

Do not use any components other than those supplied with the system. Each
component is an integral part of the system and incorrectly matched or unsuitable
components may cause engine failure at worst, or may not produce the best results at least.

NOTE: Remember that any weakness in the original design of the engine and transmission will be brought
nearer to it’s limit when large amounts of nitrous are used. Therefore it is advisable to strengthen any
such known weak components before too much power is added. It would be impossible to give details
for every vehicle as to exactly what mods will need to be carried out and at what % increase. However
we can say one thing for certain: the more power that you want, the greater the need to make
modifications. The areas that may need modifications are: fuel system, ignition components(as listed
above), head gasket, pistons, connecting rods, and clutch.

Premium Member
2,994 Posts
Discussion Starter #16 (Edited)

Premium Member
2,994 Posts
Discussion Starter #17
Well i think that just about covers the basics of fitting a system, but just don't blame me if you bu**er it up OK.
And for the love of god..... don't buy anything unless it was made by wizards of nos!

Feel free to ask questions and ill help if i can, or at least try to point you in the right direction.

if you spot any mistakes... or just don't understand my ramblings:eek: give us a pm and let me know:d

0 Posts
built block or no? thats the major question... with a built block, i wouldnt see why itd be a problem... itd act like a nitrous system on a carburated engine.. spraying before the blower. they do that all the time

Premium Member
589 Posts
Good write up !.

I used to have a Chevrolet Camaro Z28 IROC-Z 5.7 V8 some years ago. I fitted a 150bhp wet NOS kit to that.
It was huge fun and would light up the rear tyres at 70mph !.

Very expensive to run though, and with large jet kits such as the one I used, a whole bottle would only last a few mins :-(
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