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Old 04-21-2002, 05:50 PM   #1
Kevin Thomas
Street Racing Instructor
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Join Date: Jul 1999
Location: 1997 OBS, 1996 SVX, 1988 RX
Vehicle:
1989 1989 XT6

Default Zex Nitrous Jetting equals what

I purchased a Zex kit without instructions or anything. I currently am supposed to have a 50 shot jetting used according to my shop. Since they are 2hrs away from me (travelling one way), I hope some of you Zex users may be able to help me.

First here is the silly question. Where is the jetting located? It's raining outside right now and getting dark but I'll be changing it sometime this week. I looked on the purple Zex computer Friday when I was testing it but didn't see it on there. The spray is hooked up to my JC Sports intake. I haven't checked that as of yet.

2nd question: Could you all post what your jetting size is supposed to equal as far as horsepower is concerned?

Here are the jetting sizes that I have in my glove compartment.

.34

.35

.38

I'm assuming I have a .35 or .36 (or maybe .33 ) being used right now but I have to check. I didn't see anything on the Zex site as far as what jetting size equals what in horsepower. My car seems dog slow and barely moves with the jetting I have in it now but I don't want to go to big by mistake. Thanks for any help.

"Nitrous Novice"
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Old 04-21-2002, 10:06 PM   #2
jasona
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Default

there is a jet inside the nozzle inserted into your intake, and another inside the fitting on the box labeled "intake"

i *think* the jet labeled .38 is the 75 shot, .36 is a 65 shot, and .34 is a 55 shot, but im not too sure bout that part.
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Old 04-22-2002, 12:08 AM   #3
Kevin Thomas
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Default Two jets?

Quote:
Originally posted by jasona
there is a jet inside the nozzle inserted into your intake, and another inside the fitting on the box labeled "intake"
Now it's confusing. My Nos nitrous kit only has one jet that I have to change. Are you telling me that with the Zex nitrous kit that I have to change two separate jets at the same time?
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Old 04-22-2002, 12:53 AM   #4
jasona
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yeah. there are 2 jets. it has to do with the way the zex kit mixes the nitrous. the NOS kit and most others have a solonoid, but zex doesnt, it has that little control box thingy, and 2 jets. its supposedly safer that way.
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Old 04-22-2002, 06:51 AM   #5
Kevin Thomas
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1989 1989 XT6

Default Anyone!

Quote:
Originally posted by jasona
i *think* the jet labeled .38 is the 75 shot, .36 is a 65 shot, and .34 is a 55 shot, but im not too sure bout that part.
Thanks! Is there anyone SURE about what size jetting equals what in hp? Come on Zex people. Quit shaking in your boots. This is an easy one.
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Old 04-22-2002, 05:08 PM   #6
Kevin Thomas
Street Racing Instructor
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Location: 1997 OBS, 1996 SVX, 1988 RX
Vehicle:
1989 1989 XT6

Default Changing Jets

Quote:
Originally posted by jasona
yeah. there are 2 jets. it has to do with the way the zex kit mixes the nitrous. the NOS kit and most others have a solonoid, but zex doesnt, it has that little control box thingy, and 2 jets. its supposedly safer that way.
Thanks Jasona for your help. I called Zex while at work and had to wait 25 minutes for help. I actually fell asleep on the phone, at work. How about that?

I'm typing this here for reference purposes for me (since I have no manual) but it may help somoene else in the future. Here is what I was told.

Like you said, there are two jettings that need to be changed. The one in the nozzle (or the one being injected into the intake) and the one on the fuel jet.
  • 55 shot = .32 jetting in nozzle, .36 jetting in fuel jet
  • 65 shot = .35 jetting in nozzle, .34 jetting in fuel jet
  • 75 shot = .38 jetting in nozzle, .32 jetting in fuel jet

Now it is starting to make sense. More nitrous equals a wider opening in the nozzle to inject more nitrous. The more nitrous being injected, the more fuel pressure is needed. To get a higher fuel pressure, you close the fuel opening/spray even more, thus the jetting holes get smaller with every higher shot.

My opinion: Also note that the nitrous jetting goes up/down in increments of 3 while the fuel jets go up/down in increments of 2. You can vary your jetting to get different shots (Ex: 60 shot = .34 jetting in nozzle, .35 jetting in fuel).

Ok...I got it now. L8Rs

Last edited by Kevin Thomas; 04-22-2002 at 05:16 PM.
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