installing a wet nitrous system (zex)

tannerc91gt

This last 25% is foreign territory at this point
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Nov 29, 1999
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Indiana
i had a hard time finding good info on nitrous installation online so i figured id try to help out others by posting up how i did mine.

First, Mount bottle brackets on right side of spare tire well ( I had to lower gas tank to bolt them in firmly but there are other ways of securing them) this is a good start because it helps determine where you will mount the nmu later
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Strap in bottle and run line any way you would like, I ran mine under the carpet on the passenger side and then through the ovel shaped grommet where the harness comes through, obviously you only have so many feet to work with so test measure first. Mount Nitrous Management Unit keeping in mind that the nozzle lines are only 2' long so this must be within a 2' range of the air intake. I mounted mine under air intake but this area is unavailable to those with the stock air box so mounting on the side of the engine bay is also an option. You can now attach the nitrous feed line.
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attach the OUT lines to the NMU and then decide where you'd like to install the nozzle. The nozzle must be placed after the MAF meter and at least 4" upstream of the TB. It is easiest to remove the elbow Before drilling. Also keep in mind that the nozzle opens at an angle and must be aimed up into the air intake for proper flow.also be aware that the hood must be able to close with the nozzle in so mount the nozzle at a side angle on the elbow. Be careful when drilling as you don't want to put a second hole through the bottom of it and be sure to clean out rubber shavings before re- installing

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Located behind the alternator, the shrader valve is the perfect place alternator, the shrader valve is the perfect place to tap into the fuel system. Once you have relieved fuel pressure from the system by Pulling the electrical plug at the bottom of the red inertia switch located behind the paneling on the drivers side rear in the trunk,run the car until it dies. You can then remove the cap and remove the fitting from the schrader valve and screw in the line for FUEL IN. Be aware that fuel is going to come out of the valve after pressure is relieved, use a shop towel to help contain the fuel. Now that all the lines have been run the NMU must be set up to operate at WOT. This can be done by attaching the white wire from the NMU to the green wire coming from the TPS sensor. This is output voltage line. I used bite Connectors (you can buy them at radioshack for $2).
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next, the arming switch must also be Installed as to supply power to the NMU. Run the red wire through the fire wall and attach it to the arming switch (I mounted mine on the side of the steering column, there isn't really any better place to put it without drilling huge holes in the dash). You must then run a wire off the arming switch to a 12v power source under the dash. I Used a fuse tap ($2 at oriellys) and got power from the A/C fuse.Once that is complete, attach the black ground wire coming from the NMU to a ground source using a crimp on O-ring. Now the nmu should have power when the arming switch is flipped on. Next, "Turn the cars ignition on but DON'T START IT. Turn the arming switch to ON, then go to the NMU and located the 'Push Button'. Depress it, and then release it. Observe the NMU's operation light. At this point it should be RED. The RED light informs you that the NMU's activation switch is in the 'LEARN' Mode. Go back to the inside of the car and depress the gas pedal to the floor for 10 seconds. Release the pedal and go back to the NMU and observe the operation light. At this point the light should be flashing continuously from RED to GREEN to OFF. This is the NMU's way of telling you that it has successfully learned the voltage curve of your motor's TPS. Go back inside your car and turn OFF the arming switch, then turn it back ON. Go back to the NMU and observe the operation light. It should be solid GREEN. This informs you that the system is armed and ready to activate at WOT. Return back to the driver's seat and depress and release the gas pedal several times. You should now be able to hear the solenoid 'click' each time you reach WOT. Your activation switch is fully programmed and ready for use" from corral

Now your nitrous system is fully installed and ALMOST ready for use.

The final checklist includes buying 1-2 step colder spark plugs (I used autolite 23's gapped to .35)
A nitrous bottle pressure gauge ( operation PSI is between 950-100psi. you can operate below this PSI but you will notice a significant loss in power.) I got the zex version from summit for $40.
Also, timing must be retarded to the specs in the manual, I'm running a 125 shot so for me it ZEX suggested 4* retard to stay on the safe side. i am running at 10* base timing and have yet to have any problems.

Feel free to post any comments or corrections as well as any questions.
 
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Nice Writeup!!!!

One thing when using a wet nitrous kit its best not to have a under the hood filter system, incase of a nitrous backfire and it should blow your air filter off it wont catch your engine bay on fire and destroy your car. Very nice Writeup, just something I have seen happen a bunch (Not To Me But People I Know).

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btw - Nitrous feels great doesnt it?
 
vent tube off the bottle has nothing to do with a intake backfire, with a fendermount cold air it will blow inside your fenderwell and "hopefully" not hurt your car, but inside the engine bay there are wires, ect which can catch on fire. And if its a street car i would hope you would run a air filter?
 
It's all I could afford at the time, I will be upgrading to a fenderwell eventually, but yes nitrous is some badass stuff, curious how much of ashot the stock motor can handle, thinking about tryin out a 200 shot
 
Also you only need the blowdown for track use, and I have it and will be installing it as well,but I have a pressure gauge that I monitor constantly
 
i know the tube dont have anything to do with the back fire. i was just saying he needs 1 because if it does blow and u are at the track and it will fill the car up fast and hope u are not in it. when i was saying about the filter i ment to just pull it off when u are spraying it like that
 
http://emob1005.photobucket.com/albums/af171/tannerc91gt/IMG_0270.jpg

as you can see, the nozzle is angle cut and sprays up the intake, not into the opposite wall, oh and the reason you don't put it closer,it has to have space to mist and mix with the air, so if you put it up by the TB like you suggested, you can cound on picking up all the pieces of your intake on the track
 
http://emob1005.photobucket.com/albums/af171/tannerc91gt/IMG_0270.jpg

as you can see, the nozzle is angle cut and sprays up the intake, not into the opposite wall, oh and the reason you don't put it closer,it has to have space to mist and mix with the air, so if you put it up by the TB like you suggested, you can cound on picking up all the pieces of your intake on the track


i know exactly what a nozzle looks like no need for the picture.. the straight side of the nozzle doesnt look square to the inlet pipe. if its not square its going to spray into that flex part of the inlet pipe. which isnt a good thing to be doing.

yup... but its ok the OP has it under control. all the top nitrous racers running direct port and plate kits have it all wrong since it doesnt have time to mix up with the air.

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fulton must have this thing ALL wrong
 
Not sure why you feel the need to come in bashing me, I don't know you but your obviously a nitrous expert, all I tried to do was show how I did it because it's hard to find info on it, I did not say this is the ONLY way you can possibly install a wet kit, I appologize that I listened to what zex suggested instead of asking you.
 
damn if you think thats bashing ill have to be easy on ya... anyway... it doesnt look square in the inlet pipe check that if its not you could get fuel puddling in the inlet pipe cuz of the flex joint. im fr from an expert like gene fulton jim hasley don burton and all those guys but i got a pretty good grap on things with it. even if you went 4 inches past the throttle blade your around 8-10 inches based just off memory

rather see you do things right then blow something up... nitrous has a very very bad rap cuz of people doing things wrong... save yourself the headache and the money do it right the first time.