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"Darkness"
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Discussion Starter · #1 ·
Anyone ever have a nozzle siphon fuel to the point where you no longer have good control over the fuel settings?

My first stage is a annular style NX nozzle. I spray a 26n and 20f at 6 psi. This kit on its own is very clean and predictable. It responds like it should to FP changes.

My second stage is a Nitrous Outlet 90 deg. nozzle. I had it working clean with 28n 20f at 5 psi. Then when ever it feels like it the tuneup will go fat. I never ran the second stage independently. I assume its siphoning from the second kit because the first is repeatable on its own.

I would like to put a big jet spread in to use more fuel pressure and maybe that would overcome the siphon problem. The problem with that is I already burned a plug from jamming crap in a .018 fuel jet.

Any ideas?



 

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The nitrous guy
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Mike,
I don't buy into the "siphon" stuff on any nozzle, but what I do see, is the fact that your 90* nozzles do not have good placement. They are so low in the runner, that you can't tip then down and actually have them spray down the runner. The second pic is a dead giveaway. Just look at where that nozzle is pointing and where the port actually is. The charge is actually hitting the roof just out of the nozzle and could cause some issues. I would move the 90* nozzles high on the runners and tip then down.

Monte
 

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"Darkness"
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Discussion Starter · #3 ·
Mike,
I don't buy into the "siphon" stuff on any nozzle, but what I do see, is the fact that your 90* nozzles do not have good placement. They are so low in the runner, that you can't tip then down and actually have them spray down the runner. The second pic is a dead giveaway. Just look at where that nozzle is pointing and where the port actually is. The charge is actually hitting the roof just out of the nozzle and could cause some issues. I would move the 90* nozzles high on the runners and tip then down.

Monte
I see your point but the annulars blow straight onto the floor of the runner as well. The first kit rides the floor and the second rides the roof. Maybe it is my problem.

I want to do some tests with the 90 deg. nozzles and see if there is a vac. on the fuel side while spraying.

But like you say. It could be a placement issue.
 

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Mike,
I don't buy into the "siphon" stuff on any nozzle,
Monte
I feel the same way about this. Why do you think that the "syphon effect" is all hype?
 

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The nitrous guy
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Mike,
Look a little more closely at where the nozzles point and where the runner actually is. While your annulars could be tipped back toward the plenum a little more, they still have a pretty good placement and are more or less blowing right down the runner with the intake charge. The 90* nozzles never have a chance to get in the stream, as they appear to hit the roof immediately after exit. Not familiar with that nozzle and how the discharge flows, but that would appear to be the case.

As far as the "siphon" effect, I just don't buy it. A nozzle and jet combination flows what it flows at a certain pressure. I just don't see port velocity having enough draw, to pull any extra fuel through the nozzle. That would take a tremendous amount of pull, to overcome your regulated fuel pressure and draw in more fuel. Sorry, don't buy it. Just advertising hype in my opinion. There is no way that I know of to truly duplicate the port dynamics of a running engine at full song, with 2 or 3 guns on, so would hard to prove one way or the other.

Monte
 

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"Darkness"
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Discussion Starter · #6 ·
Monte,

The 90 deg. hangs into the port a bunch so it does not hit the roof untill it is down the runner some.

The siphon I'm talking about is not from port velocity but from the nitrous pressure exiting the nozzle tip possibly drawing a vac. on the fuel side. Its just a guess and I have no data to prove it.

I'll look into it a little more. The next time I will be more carefull with nozzle placement.

Here is the nozzle. The nitrous exits across the fuel outlet.

 

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Anyone ever have a nozzle siphon fuel to the point where you no longer have good control over the fuel settings?

My first stage is a annular style NX nozzle. I spray a 26n and 20f at 6 psi. This kit on its own is very clean and predictable. It responds like it should to FP changes.

My second stage is a Nitrous Outlet 90 deg. nozzle. I had it working clean with 28n 20f at 5 psi. Then when ever it feels like it the tuneup will go fat. I never ran the second stage independently. I assume its siphoning from the second kit because the first is repeatable on its own.

I would like to put a big jet spread in to use more fuel pressure and maybe that would overcome the siphon problem. The problem with that is I already burned a plug from jamming crap in a .018 fuel jet.

Any ideas?



What did I tell you stupe! Never mind asking everyone in the world. Get off your lazy, no good, good for nuthin ass, and stick a vacuum gauge on the nozzles.
 

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"Darkness"
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Discussion Starter · #8 ·
What did I tell you stupe! Never mind asking everyone in the world. Get off your lazy, no good, good for nuthin ass, and stick a vacuum gauge on the nozzles.
I'm trying to think if I ever asked your opinion. Wait a minute....NOPE!

It sounds like a smart idea. Have you always been this smart or is this something new?
 

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Mike,

As far as the "siphon" effect, I just don't buy it. A nozzle and jet combination flows what it flows at a certain pressure. I just don't see port velocity having enough draw, to pull any extra fuel through the nozzle. That would take a tremendous amount of pull, to overcome your regulated fuel pressure and draw in more fuel. Sorry, don't buy it. Just advertising hype in my opinion. There is no way that I know of to truly duplicate the port dynamics of a running engine at full song, with 2 or 3 guns on, so would hard to prove one way or the other.

Monte
I have the same thinking about it, But I just can't help but think that the idea of nitrous flowing out of the nozzle can create a vacuum to pull fuel out of the nozzle, or so that is how it is told to me. I still can't see how that it can create enough vacuum to make a difference.
 

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"Darkness"
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Discussion Starter · #13 ·
the fuel reg controls fuel flow, if the siphon was issue, what happens when the valves are closed, vacuum would become pressure in that runner, the n2o nozzle is still flowing, but the fuel sys does not become pressurized by the n2o sys does it?
How much positive pressure have you measured inside the intake runner at wide open throttle?
 

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Now Mike, that is an interesting question........

I've heard from some reliable sources that one of the main reasons the nitrous cars have such a problem with turbo (or blower) cars is due to the fact that at a certain point you just can not add any more nitrous. Since the throttle bodies (or carbs) are open to the atmosphere the nitrous will eventually come out the top! On the other hand, when you have a pressurized system from a blower or a turbo that is not going to happen.

I would think that point of diminishing returns is soley based on the combo. The larger the motor, the better the heads, etc.... the more nitrous you can add before you just can't get anymore into the motor.

With the turbo or blower, just keep turning-up the boost! Sure, at some point they will start to fall-off, but I doubt they will ever not make more power, especially with a turbo..................
 

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I'm not the sharpest tool in the shed but I'll share a few things I have found over the years.....

Back when I check a Soft Plume style nozzle just for grins, it pulled about 1 inch of vac. with a .032 jet in it..... For what that's worth !! ;)

Another finding in fooling around with the Soft Plume nozles.... They don't exit and flow at a real 90 degrees... I have even milled the shelf off the bottom and used them as an Annular style nozzle in a few old cases back when I worked for NOS...

Is nozzle placement really that critical ???? :confused: Again, while I was working for NOS I was at a race trying to help a guy out, long story short, the guy I was helping had screwed some Annular nozzles inplace of a set of 90 degree nozzles and the thing actually ran fine once I straightened his tune up out a little... Not saying this is ideal... Just was like the straw to break the camels back for me on nozzle placement... ;)

Some nozzles do work on a siphon effect, as well as the depth you mount them at effects the tune up. This is directed towards an Annular style nozzle. If you look at how the Speedtech and Fulton nozzles are made and mounted you'll know what I mean. This is why many have issues trying to tune these systems as well as have to run larger jet spreads and lower fuel pressure......

Mike, if you would like to run larger jet spreads and higher fuel pressue, don't be a pussy !!!! Put a LARGER nitrous jet in that thing..... Not a smaller fuel jet !!!! :p:p LOL

Just my two cents for now.... Later.. SJ
 

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"Darkness"
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Discussion Starter · #17 ·
Mike, if you would like to run larger jet spreads and higher fuel pressue, don't be a pussy !!!! Put a LARGER nitrous jet in that thing..... Not a smaller fuel jet !!!! :p:p LOL

Just my two cents for now.... Later.. SJ
Ok Trovato! :p

38n/26f in each kit should work mint in my little 407. And the FP will be right where I want it.
 

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I'm not the sharpest tool in the shed but I'll share a few things I have found over the years.....

Back when I check a Soft Plume style nozzle just for grins, it pulled about 1 inch of vac. with a .032 jet in it..... For what that's worth !! ;)

Another finding in fooling around with the Soft Plume nozles.... They don't exit and flow at a real 90 degrees... I have even milled the shelf off the bottom and used them as an Annular style nozzle in a few old cases back when I worked for NOS...

Is nozzle placement really that critical ???? :confused: Again, while I was working for NOS I was at a race trying to help a guy out, long story short, the guy I was helping had screwed some Annular nozzles inplace of a set of 90 degree nozzles and the thing actually ran fine once I straightened his tune up out a little... Not saying this is ideal... Just was like the straw to break the camels back for me on nozzle placement... ;)

Some nozzles do work on a siphon effect, as well as the depth you mount them at effects the tune up. This is directed towards an Annular style nozzle. If you look at how the Speedtech and Fulton nozzles are made and mounted you'll know what I mean. This is why many have issues trying to tune these systems as well as have to run larger jet spreads and lower fuel pressure......

Mike, if you would like to run larger jet spreads and higher fuel pressue, don't be a pussy !!!! Put a LARGER nitrous jet in that thing..... Not a smaller fuel jet !!!! :p:p LOL

Just my two cents for now.... Later.. SJ
Imagine that! Real world experience!
 

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"Darkness"
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Discussion Starter · #19 ·
I did a few tests tonight with a vacuum gauge hooked to the fuel inlet of my nozzles. I first tested the 90* nozzle. While spraying nitrous it will pull .25 inches or less. Not anything to worry about. Then I tested the annular nozzle. While spraying it pulled 5 inches of vacuum. I was surprised to see this. I have no tuning issues with this nozzle. I'm going to guess 5 inches will not play a big part in the fuel curve. So I'm done looking for siphon issues.

I need to think a little smarter about this. I could be over analyzing or not factoring in certain conditions. I think the tuning window is smaller when you are spraying more.

I did learn something. My system has very little pressure drop after spraying both kits for 8 seconds. The main line pressure before the solenoids drops 60 psi and it takes 8 seconds to get there. I'm using one 15lb bottle.
 

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The nitrous guy
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I have tested this "siphon effect" on a couple cars that I have loaded up with Racepak sensors. I have tried a bunch of different nozzles and a lot of different tune ups, never found anything. I do think nozzle placement has an effect though. Why do you think the same tune works better as you move it up the runners. If you have a manifold with 3 guns, one low, one high and a plenum system, with the same jetting, the plenum is always faster and hits the hardest, the low system is always the slowest and softest. Nozzle placement and time to atomize the mixture is the difference. Sure, they will work anywhere, but some spots are better than others. I have a good example of this. I recently flowed a manifold for a guy that runs a class limited to a single fogger. He runs some really big stuff. The intake was done by someone else and the nozzles were Annulars, that were placed extremely low in the runner, tilted way over, more or less pointing right at the intake valve. The nozzles were so low, the heads were notched for clearance. He also sent me a manifold with nozzles in a more conventional spot. I flowed both and they ended up flowing the exact same numbers with the same jetting. We tried the "trick" manifold numerous times and the car would not go 10 feet before launching the hood with a big fireball. Moved the tune every where, rich, lean, more timing, ramped timing, nothing helped. Finally, out of frustration, changed the manifold, went to the initial tune and the car went right down the track the first hit. The conclusion I came to, was that the tune was so big and the nozzle right on top of the valve, that the charge


never got a chance to mix and the cylinder was just basically getting a big load of fuel as the nitrous went right by and out on the overlap. Have no proof, but it seemed the only logical explanation.

Monte
 
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