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Discussion Starter #1 (Edited)
First off, I attempted to post this in the DIY section. For some reason the site would not allow me access to that portion of the site, so hopefully this is OK!


Where do we begin? It seems that many people have posted threads and comments in regards to nitrous kits and how they are installed on our generation civics. There doesn't seem to be an abundance of information in regards to the topic of nitrous fed 8th gen civics, so hopefully I can answer some questions and provide some insight and shed some light on how a basic nitrous setup works with an 8th gen.

Nitrous has been around for a very long time, and it is very well known around the car community. Some praise juice as a miracle, and others ridicule it as an abortion for your engine's life. This is because the truth lies on both ends of the spectrum and everywhere in between. Nitrous seems to be the black sheep of the forced induction world. Most people have heard so many nitrous horror stories that they are just too afraid to try it.

Here is the reality. Nitrous, along with any form of forced induction, will work as well or as poorly as you dictate. I genuinely believe that the reason you see so many success stories with Supercharging and Turbocharging is because these systems are very expensive, so the owners who pick these routes will usually also make sure that the system is installed correctly and is working properly, sparing no expense. Nitrous kits on the other hand are very cheap. People can easily get their hands on a $250 nitrous setup, do a half a$$ installation and blow their motor within the week because they didn't ensure the proper measures were taken to keep things as safe as possible. With these things being said, also understand that nitrous does have its limitations, even if you do everything right.

You must understand that any form of forced induction will increase cylinder pressure. Over time, this increased pressure will create extra strain on piston rings and other internals. So even if everything is set up properly, nitrous WILL shorten the life span of your engine. Its like eating a poor diet. You might only live to be 70 instead of living to be 80. If this is a big problem for you, then you probably shouldn't be modifying your vehicle.

Also understand that every motor has limitations. Many nitrous explosions occur on crappy little motors that aren't built to handle the task. The K20z3 is not one of these motors. The K20 is a stout motor and will easily handle a basic shot of nitrous without a hiccup. Many people in the RSX community are running over 100 shot without issues. However, not all K20Z3s will handle the same amount of abuse. Mileage and condition of the motor are a big deal. So make sure your motor is healthy enough to be sprayed. (compression test)

I chose a 65 shot on my vehicle because it can be supported with the stock fuel pump, and it provides a significant boost in power. So with that said lets go over what I bought for a basic 65 shot setup. This is just how I DID MY setup. Always remember there is more than 1 way to skin a cat.


1.) NECESSARY: Bottle and brackets. This will be the storage system for the nitrous. These can be purchased in different sizes and colors. 10lb is the most popular

2.) NECSSARY: Nitrous feed line. This will supply the nitrous from the bottle to the solenoid. Sold in different lengths. It is a good idea to measure out the distance between your planned bottle location and solenoid location so the line is the right length.

3.) NECESSARY: Nitrous solenoid. This is a mechanical device that will allow nitrous to pass through after electrical current is provided.

4.) NECESSARY: Fuel feed line with necessary fittings. This is just going to be a rubber fuel line that provides fuel to the fuel solenoid

5.) NECESSARY: Fuel solenoid. The same as the nitrous solenoid, but it dictates the flow of additional fuel.

6.) NECESSARY: Fogger nozzle. This nozzle will tap into the intake tube. It is supplied with both nitrous and fuel. This piece will atomize the mixture and spray it into the intake.

7.) NECESSARY: Nozzle Jets. Also referred to as "pills" These are small fittings with a very small hole in them. The size of the hole determines the flow of nitrous or fuel that will make it through the nozzle. Larger shots will use jets with larger holes. For a 65 shot the jets needed will be .018 fuel and .035 nitrous

8.) NECESSARY:Solenoid to nozzle feed lines. This will provide the flow of nitrous and fuel from the solenoids to the nozzle.

9.) OPTIONAL: Colder spark plugs. I use the term optional loosely. Stock spark plugs will allow a greater chance of detonation. No Bueno. Spend the 25 dollars on a set of colder plugs. There are several options.

10.) OPTIONAL: Inline fuse holder and 30 amp relay. This will keep the circuit protected from frying. It would be silly not to buy these 2 items.

11a.) OPTIONAL: Master arming switch. This is a toggle switch that will be run in sequence with 2 other switches on my setup. This means that the nitrous system will only operate if this toggle is in the ON position.

11b.) OPTIONAL: Zex electronic TPS voltage WOT switch. This is a box that has the ability to learn the voltage curve of the stock drive by wire throttle. This means that when the throttle is wide open, the switch will complete its portion of the circuit, allowing the nitrous system to activate.

11c.) OPTIONAL: RPM activated window switch. This is the 3rd part of my activation system. This box will tap into the tach signal wire and allow you to set a "window" in which the switch will complete a circuit. This means you can set the switch to activate at a desired RPM and then cut off at another RPM. This is an excellent thing to have because it does a lot of thinking for you. You really shouldn't spray nitrous in low RPM scenarios, so you can set the nitrous to activate at 5000RPM for example. Then you can shut the window at 8000RPM so that nitrous will not continue to spray in the event that you hit the re limiter.

11a, 11b, and 11c work together as a system. Consider them a team. The nitrous system will only be able to activate once all three of the switches' prerequisites have been satisfied. This means that nitrous will only spray at WOT between 5000 and 8000 rpm. And I have the ability to shut the system off completely with the master arming switch.

You could elect to replace this system with a momentary push button switch like you see in the fast and the furious, but this is a terrible idea. If you activate your system at part throttle, low rpm, or hit the rev limiter and the ecu cuts fuel to the motor, you can kiss your K20z3 goodbye. These switches will cost around 150 dollars, but they are well worth the investment. They will prevent a $3000 mistake.

Expect some miscellaneous wiring and connectors and assorted hardware expenses.


STEP 1. Find the ideal spot to place your bottle. Many people like to place the bottle in the spare tire well. I chose to mount mine on the board that covers the spare. I wanted to keep my spare tire. I mounted my bottle to the drivers side because the feed line will end on the drivers side near the intake. Another reason I placed it on this side is to keep the feed line on the opposite side of the exhaust piping. This also provides a decent amount of space on the passenger side of the trunk for other cargo. This also creates a shorter path for the feed line. Orientation of the bottle is important. It has a feed tube inside it that angles down and towards the bottom of the bottle. You want the bottom of the bottle to face the rear of the vehicle because the force of acceleration will force the nitrous to the bottom of the bottle.



tighten the bottle in the brackets. Place it in the desired location and mark the holes for the mounting hardware.



Find the right size drill bit for your mounting hardware and drill the holes to mount the bottle. Be careful not to drill into your spare tire!





Now you can mount the bottle.

STEP 2. Now it is time to run your nitrous feed line. This is the only portion of the install in which you will need to work under the car, so go ahead and grab your jack and stands and get the car in the air. Some people run their feed line inside their vehicle. I don't like the idea of my cabin filling with nitrous, so I always run my feed lines underneath the car.



There is a black tray under the trunk. Im not really sure why Honda put it there, but it works nicely to protect the nitrous line. We are gonna remove this cover in order to gain access to the trunk floor. It has a few pop clips in it and some 10mm bolts. Take these out and set the black cover aside.





Now drill a hole in the trunk floor large enough to fit the an line from the nitrous feed line.



Now go back into the trunk and drill another hole in the trunk carpet to run the nitrous line through



Run the nitrous feed through the hole you made in your trunk floor



Now the nitrous feed is a steel braided line, and is pretty tough, but I wanted it to be extra safe going through the hole I drilled in the trunk floor. So I decided to cut a piece of fuel line down the center to insulate the nitrous line. I taped it onto the feed line in the spot where it would feed through.







At this point you can place the black cover back in place. The nitrous line fits through the gap at the top. It is now protected adequately by the cover.



Now run the feed line past the control arms and zip tie it in a safe place where it is free from the chance of being pinched. The ultimate goal it to run the feed line along the same path as the brake lines. Then zip tie the feed line to the brake lines.



At this point your feed line will be up in the engine bay. WOOT WOOT!




STEP 3.

This is a good time to mount your solenoids. Many people run the zex kit which places them in a tidy box. I went with Nitrous oxide systems solenoids because I like the idea of only needing to replace one if I have an issue with one instead of purchasing the entire zex box.

This is one of those times where you need to get creative. I went out to pep boys and bought a 3" slotted square sheet. This part is made by HILLMAN. Lot number is HPM07829. H number is 884483.

The holes in this sheet are spaced perfectly for the mounting points on the NOS sniper solenoids. I decided to mount my solenoids next to the intake, underneath the cowl panel. You may need to pick a different location depending what intake you have, how long your secondary feed lines are, and where you plan to put your nozzle. For my application, this solenoid mounting location puts the nozzle right where I wanted it. plus they fit there nicely. The 8th civic is fairly limited on space for the solenoids.






STEP 4.

At this time I chose to run my fuel supply line. This is the line that goes from the stock fuel line to the fuel solenoid.

Go ahead and remove the solenoid from the mount, because we will need to work with it. If you mount your 'noids in the same spot as me, then you will need a 90 to get it to tap into the fuel line. It is not absolutely necessary to use a 90 degree fitting, but it is recommended to keep any hard bends out of the soft fuel line. You definitely don't want the line to kink and for your car to lean out and explode.

It is also a good idea to add a fuel filter to the setup as well. I got a NOS fuel filter. I am unsure of the part number. The 90 degree fitting I got is made by dorman. I purchased it at autozone for about 2 dollars. The part number is 321162.

This is a diagram to show the trajectory that the feed line will need to take.



Also, go out and get some thread paste. It holds much better than the tape. The take can break apart and clog up the solenoid. It also doesn't provide a very good seal. I have heard of people using thread locker as a sealant, but these are pieces of soft metal, and I doubt you would break them free to take them apart if you used thread locker.



Thread the 90 degree fitting into the solenoid and make sure it is oriented so that the female end will face the fuel line. After you have completed this task, thread the filter into the 90 degree fitting.



At this point, you can remount the solenoid to the bracket.

Next you will need to cut a piece of fuel line to the required length. You can then clamp the fuel line to the filter, and then add a barbed tee t the other end of the fuel line. This is how we will tap the stock fuel line.



Now remove the oem fuel line that is next to the valve cover. It clips into place on each end. It is rather simple to remove. I have heard to not use this line for fuel supply, but im not really sure why not. It provides easy access and the shortest length of travel for the fuel supply. In my opinion, the shorter you keep lines like this, the better.



Now remove the fuel hose from the fittings. I had to cut them off with a razor blade. prepare the new section of fuel line to be clamped onto the fittings.



Now you can install the tee into the line. Tighten the clamps well! Reinstall the line and hook the fuel feed line to the open end of the tee. It looks fairly tidy once finished.



At this point. Cycle the key to the on position so that the fuel pump will prime the system. DONT START THE CAR. Get out and check for leaks. If no leaks are evident, go ahead and start the car. Let it idle for a couple of minutes. If no leaks are evident, then take the car for a quick drive and then check for leaks one last time. If you did it right, it should be bone dry and functioning flawlessly!

STEP 5.

Ok, at this point, the best thing to do is mount your nitrous nozzle.

You must mount the nozzle in front of the MAF sensor or you will risk freezing and ruining the sensor!

Remove the intake from the car and go to a clean work area. Strip the intake down and remove the MAF. Put the maf in a safe location!

Drill the correct size hole and use a tap to thread the intake. What size you need will depend on what size your nozzle is. 1/16 npt was the size of my nozzle. They are also sold in 1/8 npt. Taps for 1/16 are hard to find. Luckily my local harbor freight had it in stock. 1/8 npt is an easy tap to find.



Now try to thread in the nozzle. It should fit nicely. I covered the threads in black RTV to create a nice seal! Make sure that the nozzle is pointing in the correct direction!



Now you can go ahead and reinstall the maf and then put the intake back into the car.

Now is a good time to thread the feed lines into the solenoid outlets. Use the Teflon paste! not the tape!



Next, install your jets into the nozzle, then put the feed lines onto the nozzle. The ends that attach to the nozzle are AN fittings and do not require Teflon paste.

At this point, the plumbing portion of the install is finished! congrats! it was tough, but you pulled through!



STEP 6.

Swap out your stock plugs for the colder spark plugs! I didn't include any pictures of this. If you are this far into the install, then you can change your plugs without issue. The plugs I used were NGK BKR9EIX. They perform flawlessly.



STEP 7.

Now we will move on to, what is in my opinion the most crucial element of the install, wiring the system. Take your time. This step is very easy, but it is tedious. Just follow the diagram I provided and the system will function flawlessly. Try to keep the wiring clean. It can get messy easily!

Start by plotting out where you will mount your switches. I chose to mount my arming switch in front of the shifter and the WOT switch, relay, and window switch on top of the underhood fuse box. I didn't take any pictures during the install, but it is fairly straight forward. Here are the finished products.

I purchased my window switch from summit racing. It is actually made by summit racing. it is about 60 dollars shipped and it works perfectly. The TPS WOT box I used was made by zex. There are other alternatives to these units, but this is just what I decided to use for my application. Some manufacturers make a combined TPS switch and window switch. I intended to buy the combined unit from ZEX but it has been discontinued to my knowledge.

For the record, this setup works very well. I have no issues with either of the units.










https://youtu.be/QtojbBM0Mio

And after you complete the wiring, the system is complete! Only a few more things to do before hitting the street/track.

STEP 8.

At this time you will need to calibrate the system. Turn the key to the on position but do not start the car. Hit the arming switch. This will activate the setup mode of the window switch. From here you can adjust the activation rpm and deactivation rpm of the window for the nitrous system. You can also select the amount of cylinders, which will be the 4cyl mode obviously. There is also the option to select the window mode.

One is NO and the other is NC. NO will have the window activate at the lower RPM, then deactivate at the higher RPM. NC will have the window activate below the low rpm, then turn off, then reactivate above the high RPM.

In order to set the TPS voltage on the ZEX module, you will need to set the Summit window switch system to NC. This will allow the TPS box to power on while the vehicle is off.

Hit the program button on the Zex TPS box. The LED on the box should be displaying a solid red color. Next get into the car and depress the gas pedal all the way down for 10 seconds. Get out and check the TPS box. It should now be blinking red and green. This means the learning procedure was successful. Flip the arming switch back to the off position. then turn it back on. At this point, the ZEX TPS should be lit solid green.

Now be sure to Set the summit window switch back to the NO setting. The low activation RPM is your personal preference. I have mine set to activate at 5000 RPM.

The deactivation RPM needs to be AT LEAST 100 RPM lower than your rev limit RPM. I have mine set 300 rpm lower to be safe.


At this point, your nitrous system is ready to arm and be used. It is good practice to try the system without the nitrous bottle and see if the AFR drops. This will indicate that the Fuel solenoid is working properly. At this point, you can hook up the bottle and do a pull!

Make sure to watch for lean AFRs and if you hear or feel something that isn't right, let out of the gas and turn off the arming switch. If you did everything right and all the components of your system are in working order, then your car should be running great on nitrous!

That is all guys! Have fun and be safe! Enjoy spraying!
 

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Sub'd for updates. My buddy did this on his 8th, he was pretty thorough, but still managed to burn up some rings. I wanna see if we missed anything obvious that was overlooked in over analysis.
 

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Discussion Starter #6
I made an update tonight fellas, however it was a small one. I apologize that I cant finish the install quicker, but I am only able to work on the car late at night. I have a pretty busy schedule.

Expect it to be finished within the week
 

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I made an update tonight fellas, however it was a small one. I apologize that I cant finish the install quicker, but I am only able to work on the car late at night. I have a pretty busy schedule.

Expect it to be finished within the week
No worries brotha take your time and get it right I'm very interested in this setup so I'm patient and so should everyone.
 

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Discussion Starter #9
Just wanted to let everyone know that I completed the install this evening! I will upload the pictures and update the original post tomorrow.

I will provide a wiring diagram and pics of how to wire the system tomorrow!
 

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Discussion Starter #10
Alright guys, I added the additional steps. I hope this thread proves to be helpful to anyone that is interested in spraying their Si. It is definitely rewarding when you feel the nitrous hit for the first time. Youd better hold on!
 

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sub , new diy should be stickied as the old ones the pictures seems to dont work
and good job the install looks very clean although nitrous isnt my thing but its great to know that theres other mods that we can do to our car
 

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Alright guys, I added the additional steps. I hope this thread proves to be helpful to anyone that is interested in spraying their Si. It is definitely rewarding when you feel the nitrous hit for the first time. Youd better hold on!

Hey man first off have you done a e-dyno or been on dyno to see what power your making?
Thanks for this it will help me soon.
I'm about to start making a headlight intake and with it I plan to run nitrous. I'm running a k24a2 block k20z3 head Go Power v1r-2 cams, rrc, zdx, mega power and 3" exhaust hoping for 260 hp and 175tq but like I said I'm buying the stuff for spray and making a headlight intake super excited to spray.


Sent from AutoGuide.com Free App
 

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Discussion Starter #14
Thank you guys! I have now run a full bottle through the car with no issues. The plugs seem to be in excellent shape with the 50 shot.

Another thing I have on my setup that I forgot to mention is a nitrous pressure gauge. I try to keep the pressure around 900-1000 psi. Running the bottle under hot water seems to get it right around 950. You'd be surprised how well it will hold pressure without a heater in the summertime. In cool months, however, a heater is definitely necessary to get the pressure that high.

My car makes an estimated 220 whp off of the bottle. My trap speed it 100mph on motor so this is probably fairly accurate. The 50 shot seems to definitely add 50 whp on the butt dyno. No way to know exact numbers though.
 

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Discussion Starter #15
I'm sure a stock r18 would handle a 50 shot with no problem. I've never personally seen anything fail with just a 50 shot and a proper install with a window switch and wot switch.

Most nitrous failures come from improper air fuel ratios and timing rather than the engines inability to handle the added power.

Learn to read spark plugs. You want them to look tan. All 4 should look the same. Plugs are the best way to tune your air fuel on spray imo.
 

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Do you know if they have any kits that comes with everything rather than buying it separately? I was looking into the Zex it's just they have a few different models.
 

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I want to hide a bottle somewhere but cant figure out where to hide it. I cant put it in the trunk because i use my car for work. uber to be specific
 

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How safe exactly is this zex kit? Im new to this. I just ordered a kit and having a
Coworker that has a foxbody on nitrous as well install it.
My internals are comepletely stock. I Just have bolt ons with a vit tune at the moment.
 
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