How is more fuel triggerd in a dry nitrous setup.

sizemoremk

Registered User
I've read te NOS sites descriptoption, but I still don't get it?

From the NOS site:
We accomplish this by two methods. First, is to increase the pressure to the injectors by applying nitrous pressure from the solenoid assembly when the system is activated. This causes an increase in fuel flow just like turning up the pressure on your garden hose from 1/2 to full.
Exactly how do you get the selenoids hooked into the fuel lines to do this???


The second way we can add the required fuel is to increase the time the fuel injector stays on. This is accomplished by changing what the computer sees, basically tricking the computer into adding the required fuel.
Do they mean via EEC tuning, or is there some other way to "trick" the computer intonsending more fuel???



Thanks to anyone that can clarify this!
 
Your O2 sensor picks up the large amount of O2 from the Nitrous and thinks the engine is in a lean condition. At this point the injector stays open longer to burn up the extra O2. Be warned, only shoot the Nitrous during wide open throttle and preferably with the RPM's above 2,000.
 
You need to tap into a fuel supply to get fuel to the solenoid. This can be done a few different ways. The easiest it to tap in at the schrader valve. This is where you hook your fuel pressure gauge up to. You pull the core out and hook the Nitrous fuel line there. MAKE SURE you have a BIG FUEL PUMP. A 255lph should be used. Not sure if a 190lph would be up to the task.

I have a question though. How big of a kit can you put on a SC without fear? I had a 150hp kit on my 88TC and think it would be a kick on the SC.
 
bigg_boyys_SC said:
Your O2 sensor picks up the large amount of O2 from the Nitrous and thinks the engine is in a lean condition. At this point the injector stays open longer to burn up the extra O2. Be warned, only shoot the Nitrous during wide open throttle and preferably with the RPM's above 2,000.

The dry kit for the 5.0 mustang uses this one with two solenoids, and some kind of "nitrous regulator" I did some more research on www.NOSnitrous.com and it looks like that nitrous regulator taps into a line going from the manifold to the car's fuel pressure regulator, Tees off of that, and I assume the pressure in there triggers pressure to spool up the fuel pump???

I'm not sure why there are two solenoids, but from what I can see and have found for sale, the dry kits have 2 nitrous solenoids.

Fro that picture am I correct in thinking that the tee fitting is for dual bottle setup???
 
None2Slow said:
You need to tap into a fuel supply to get fuel to the solenoid. This can be done a few different ways. The easiest it to tap in at the schrader valve. This is where you hook your fuel pressure gauge up to. You pull the core out and hook the Nitrous fuel line there. MAKE SURE you have a BIG FUEL PUMP. A 255lph should be used. Not sure if a 190lph would be up to the task.

I have a question though. How big of a kit can you put on a SC without fear? I had a 150hp kit on my 88TC and think it would be a kick on the SC.


I said dry kit....

i found this article very interesting!


http://www.sccoa.com/sccoo/Faq/nitrousoxide.htm
 
bigg_boyys_SC said:
Your O2 sensor picks up the large amount of O2 from the Nitrous and thinks the engine is in a lean condition. At this point the injector stays open longer to burn up the extra O2. Be warned, only shoot the Nitrous during wide open throttle and preferably with the RPM's above 2,000.

doesnt the computer ignore the input from the 02 sensors at wot?
 
Your O2 sensor picks up the large amount of O2 from the Nitrous and thinks the engine is in a lean condition. At this point the injector stays open longer to burn up the extra O2. Be warned, only shoot the Nitrous during wide open throttle and preferably with the RPM's above 2,000.

Nope...the EEC ignores the o2 sensors at WOT.

It adds the extra fuel by tapping into the vacuum/boost refrence line on the fuel pressure regulator and using a small amount of nitrous to increase the pressure on that line, which will raise the fuel pressure. Just like adding boost raises fuel pressure.

The problem is, if your already at the peak pressure (w/15 lbs of boost 65 psi)your fuel pump can sustain full flow, raising the pressure higher may not supply more fuel. Several of the NOS kits advise adding an additional in-line pump to insure adequate fuel flow.

The only way I would run a dry kit was if I had a dual program chip that increased pulse with when using the nitrous.

David
 
What I don't understand is what keeps the pressure from the NO2 regulator from bleeding right back into the manifold (path of least resistance). Since it's "T'd" into the same line as the FPR and it gets it's signal from the lowerIC tube return adapter, it would seem to me that there would be a slight increase in pressure at the regulator, but the line is still open to the return adapter. I am pretty sure the 2 solenoids (in series) give the system a pressure drop to work with. There are still jets for the regulator and the No2 nozzle.

Jeff

I have one of the Mustang dry setups myself, seems like there should be a checkvalve somewhere.
 
David Neibert said:
Nope...the EEC ignores the o2 sensors at WOT.

It adds the extra fuel by tapping into the vacuum/boost refrence line on the fuel pressure regulator and using a small amount of nitrous to increase the pressure on that line, which will raise the fuel pressure. Just like adding boost raises fuel pressure.

The problem is, if your already at the peak pressure (w/15 lbs of boost 65 psi)your fuel pump can sustain full flow, raising the pressure higher may not supply more fuel. Several of the NOS kits advise adding an additional in-line pump to insure adequate fuel flow.

The only way I would run a dry kit was if I had a dual program chip that increased pulse with when using the nitrous.

David


Thanks guys!

You say 15 bounds of boost, will the nitrous have that much of an affect on boost? Or are you sayin that if you have a setup that will achieve 15 pounds of bost, that then the fuel pump must be bigger or an additional fuel pump added?


Just a note, I am lookig at the 50-75 shot, and donot want to heavily modify my 35th. If all I must do is exhaust, and have a "spare original IC tube" to replace th eone I tap into for NOS, then that would be perfect. I'm not interested in the making a lot of irreversable changes to it. I just want to hit the bottle on ocassion over at the local dragstrip and at least be able to outrun most of the ricers and the mustangs with K&N filters....
 
The higher the pressure the harder the pump works, you may end up at a point that the pump can no longer supply the needed pressure. In some cases the fuel pressures are really high (like a 150 shot) and the fuel pressure ends up going to nearly 100psi. Most injectors are unable to work at these pressures and the injector will simply not open. Usually there will be 1 (or more) injector that will stop before the others. Ouch!

I have seen weak injectors that will stop opening at much, much lower pressures, like around 45psi. I have an injector test stand and cleaner, and had a friend that had a set of injectors for his Mazda truck and it ran fine until he would mash the gas, then it would miss. We checked the fuel pressure, changed plugs, wires nothing seemed to help. I said lets see if one of the injectors are plugged. Every thing was fine and they all looked good (did cleaning and everything) until I increased the fuel pressure and around 45psi 1 stopped working. Swapped it for another and the problem went away.

Jeff
 
Last edited:
You say 15 bounds of boost, will the nitrous have that much of an affect on boost? Or are you sayin that if you have a setup that will achieve 15 pounds of bost, that then the fuel pump must be bigger or an additional fuel pump added?

I'm saying that if your car is making 15 pounds of boost without the nitrous, the pump has to operate at 65 psi. The higher the pressure you operate a fuel pump the less volume it will flow. So lets just say for the sake of this discussion that the nitrous kit adds another 15 pounds of pressure to the regulator. Now the pump will have to push 80 psi and the flow of fuel will drop, and possibly supply less fuel than it did at 65 psi unless you have upgraded to something like the 255 lph hi pressure pump I have.

I prefer the wet system because they don't increase the fuel pressure, they just supply fuel at whatever pressure your injectors are at thru a seperate nozzel, based on how must boost you have. You can easily adjust the fuel to nitrous ratio just by changing jet sizes.

David
 
The T has a jet in it. It is the same type as used in the fogger nozzle. This restricts the nitrous from going into the intake, and forces it to the regulator. In most cases, the dry nitrous kit forces the regulator almost completely closed. Changing the jet size in an attempt to increase fuel pressure even more usually does not work.

Dry kits are tested on near stock applications. If you have already done significant mods to your engine, then you need to be very careful about running out of fuel regardless of the pressure. If you run a wet kit, this removes the extra load from the injectors and does not increase the fuel pressure making things easier to setup and tune.

With both dry and wet kits, you still need to gauge whether your fuel system can support the horsepower you are making.






J57ltr said:
What I don't understand is what keeps the pressure from the NO2 regulator from bleeding right back into the manifold (path of least resistance). Since it's "T'd" into the same line as the FPR and it gets it's signal from the lowerIC tube return adapter, it would seem to me that there would be a slight increase in pressure at the regulator, but the line is still open to the return adapter. I am pretty sure the 2 solenoids (in series) give the system a pressure drop to work with. There are still jets for the regulator and the No2 nozzle.

Jeff

I have one of the Mustang dry setups myself, seems like there should be a checkvalve somewhere.
 
David Neibert said:
I'm saying that if your car is making 15 pounds of boost without the nitrous, the pump has to operate at 65 psi. The higher the pressure you operate a fuel pump the less volume it will flow. So lets just say for the sake of this discussion that the nitrous kit adds another 15 pounds of pressure to the regulator. Now the pump will have to push 80 psi and the flow of fuel will drop, and possibly supply less fuel than it did at 65 psi unless you have upgraded to something like the 255 lph hi pressure pump I have.

I prefer the wet system because they don't increase the fuel pressure, they just supply fuel at whatever pressure your injectors are at thru a seperate nozzel, based on how must boost you have. You can easily adjust the fuel to nitrous ratio just by changing jet sizes.

David

I will likely change to an aftermrket fuel pump just in case, I have no idea how old it is either... it may be original...

From a few things I read, think the dry kit is best for me, I am also concerned with the wet kit possibly backfiring with fuel in the intake?
Maybe this isn't a concern...

I am also concerned with my injectors, what is the best method for testing them, doesn't one of the "key on engine on" eec test look at individual cylinders, is this an indicator of weak injectors? What is the best method for cleaning them?

And also the O2 sensors, I guess it would be a good time to change them also, so that it more accurately asks for more fuel... Is there a recommended O2 sensor for us? Other than Autozoo parts?

I am running the autolite 103's I read earlier that these are OK with N20. I don't remember why I am running them, I read that they are 2 stages colder. As far as I remember, i thoguht they were suppose to be stock???

Thanks! I like thouroughly researching these sorts o things!

Any more ideas or suggetions woudl be greatly appreciated!
 
Back
Top