NOS 5175 running rich

[malice10985]

I complained a few months ago about being too lean when spraying. I took someones advice, I don't remember who, rerouted some vacuum lines(more appropriatley, I reinstalled the kit correctly) and repositioned my jet much further away from the MAF.

Now my cheap little sunpro A/F ratio meter says I am running pretty rich while spraying. I have the 85hp jet in the car right now.

Should I not trust the crappy A/F gauge... or will one of you guys sell me a bigger NOS 5175 jet?

Oh yeah, 76 psi of fuel held constant throughout the 2 runs I made. [img]graemlins/evilgrin.gif[/img]

[OneQuickV6]

Best thing you can do is put it on a dyno with wideband O2 capability to see if it's truely running as rich as the gauge says.

[John_D.]

Hey, congrats on resolving the lean problem.

How rich are you? Some rich is ok.

Bigger jet is a possibility.

Or a maft to lean the car out a bit.

Either way, you need a way to monitor a little more closely. The ideal way would be with a wideband. The next best is monitoring the actual o2 sensor voltages. .92v would be a good target range when spraying. Mine seems to run strongest around .94v.

[malice10985]

<blockquote>quote:</font><hr>Originally posted by John_D.:
Hey, congrats on resolving the lean problem.

How rich are you? Some rich is ok.

Bigger jet is a possibility.

Or a maft to lean the car out a bit.

Either way, you need a way to monitor a little more closely. The ideal way would be with a wideband. The next best is monitoring the actual o2 sensor voltages. .92v would be a good target range when spraying. Mine seems to run strongest around .94v.<hr></blockquote>

I like the idea of hooking up a voltmeter to the o2 sensor. I will try that. If it tells me what I want to hear, I will get a bigger jet. Where do I get one? From NOS themselves?

I would love to dyno my car, but there isn't one for hundreds of miles.

[John_D.]

hmmm, I don't know about where to get a voltmeter type gauge for the o2 sensor.

I use autotap and a laptop to monitor mine. (luckily no rivets have started popping out of the floorboard yet.) [img]smile.gif[/img]

I know there are some other people on here who have put a voltage gauge in. Seems like somebody said hanging a gauge on the line can throw the voltage off a little too though...

[malice10985]

I will rip out the current AF gauge and plug in a multimeter for a few days... maybe tape it to the A pillar. That will give me a free and accurate synopsis of my true AF ratio. Ghetto but effective.

No one knows where to get bigger NOS jets?

[John_D.]

Summitracing, jegs, etc. About $6 each. (then there's shipping...) I got another brand, maybe it was edelbrock. As long as it says "flare jet" you should be ok.

[OneQuickV6]

You can even get them (the jets) at Advance Auto Parts.

[12secondv6]

<blockquote>quote:</font><hr>Originally posted by OneQuickV6:
Best thing you can do is put it on a dyno with wideband O2 capability to see if it's truely running as rich as the gauge says.<hr></blockquote>


Dyno and wideband.

Contact NOS direct. They can assist you with jet changes.

[malice10985]

I am the biggest dumba$$ in the world. My setup was running rich because I had no jets at all. Most of the spray was leaking out of the line before it got to the nozzle.

If I plug in a jet, I will put all the spray into the engine and eliminate the rich cond. real quick.

What size do I need? I bought a 78 82 and 86 at the part store, only to find out those are not the hp ratings, but the size.

I think I need a 30 something size to get an 85 hp shot.

[camaro28]

hey dude,

you need a size 42 jet to run an 85 HP shot. Summit has em. 6.99 apiece.

[John_D.]

<blockquote>quote:</font><hr>...no jets at all. Most of the spray was leaking out of the line before it got to the nozzle.
<hr></blockquote>

I don't understand this one... The jet goes in the nozzle. With no jet, the nitrous would still go through the line and into the nozzle. Unless the fitting was not tightened down.


<blockquote>quote:</font><hr>What size do I need? I bought a 78 82 and 86 at the part store, only to find out those are not the hp ratings, but the size.
<hr></blockquote>

The 5175 kit comes with a 47 nitrous jet, even though the documentation says 45 jet.

The bypass jet is smaller. It's a 42.

If the bypass jet was missing, then there would not be enough pressure applied to the fuel pressure regulator, and the car would run lean.

Were both jets missing or what?

[malice10985]

THe jet that goes in the nozzle was missing.

with the jet missing, the nut that screws on to the nozzle is not pressed onto the line completely and there is a small gap between the line and the nut.

MOst of my spray was leaking out of this gap before it got to the nozzle.

If you take out your jet and put the nozzle back on, you can feel some play in the connection. THat was my problem [img]graemlins/dunce.gif[/img]

[John_D.]

Oh! Okay, I get it now!!! [img]smile.gif[/img]

You must have been going through a bottle of nitrous really fast with that setup!

[malice10985]

yeah, i used up a lot.

IT is all fixed now.

I think I finally got this system working correctly.

Now how about those 12's?