Robert56

iTrader: (2)

An easy way is to use your air comp. Just set your out pressure low, hook FPSS sw up to the end of your air hose. Then gradually increase your air pressure while noting the AC gauge. Also you need to hook a ohm meter up to the terminals on the FPSS. You'll be using it as a continuity checker. touch your test probes togehter, that is the signal your watching for as you increase pressure, means the sw has closed.

Unless you have a bad FPSS, it sounds like your fuel system is on a downward spiral if you have to keep going counter clockwise on setting (lowers set point). Could be a weak pump going out, a clogged filter ect. But checking set pressure and seeing if FPSS works fine will tell ya which way to go/look.

I think NX sends their sws set at 35psi to cover a multitude of cars. Myself, a drop of more than 5lbs from our 58psi means inadequate fuel system or problems. But others will say 10lbs or so.

Hey guys, sorry about being so grotchy early on in this post ('05), that was when I was dealing with my neck injury just before surgery, and the pain pills tend to make one more of an *** than normal.
Robert

DuronClocker

iTrader: (25)

Like said above, if you ran a FPSS on the outlet side of the solenoid, the system would never fire, unless you had the FPSS on a switch to disable it until after the solenoid is open, but then every time you shift, you will be back to the same thing. This could be remedied if you were to use some sort of a time delay where the FPSS signal would not be used until a desired time after the solenoid powers up, or something along those lines.

If you don't run a time delay, the the FPSS won't see pressure in the line until the solenoid opens, but the purpose of the FPSS is to not let the solenoids open unless there is adequate pressure.

A way around this I guess would be to use the pre-solenoid FPSS to control the entire system, and the post-solenoid FPSS to control only the nitrous solenoid. This way, the fuel solenoid opens, FPSS sees pressure, and allows the N2O solenoid to open. I imagine by the time the fuel at 58psi reaches the nozzle(s), the 950psi nitrous should be able to make up the small time delay.

The other idea would be to use a pre-solenoid FPSS and a pre-solenoid flow meter, but I'm unaware of how cheap and readily available a suitable meter would be.

Robert56

iTrader: (2)

You can use a signal, that would be present anytime you go wot. Then if there is pressure it'll be closed (contacts) and allowing fuel to flow. So like you said, one FPSS before noid as per normal, then one after that's controlled seperately. I guess some testing would be in order. Would this slow the fuel down and cause a lean spike, and thus the need for a time delay on nitrous side?
Robert

DuronClocker

iTrader: (25)

Or like I said, have the fuel solenoid activated by the system as normal, but use the post-solenoid FPSS to control the nitrous. So the fuel solenoid needs to open, and the post-solenoid FPSS sees a pressure, then the nitrous solenoid opens. So the fuel solenoid would be opening slightly before the nitrous solenoid, which wouldn't cause a lean spike at all.

In fact, it might even make the initial hit safer whereas with a normal setup, I imagine the nitrous gets to the nozzle slightly before the fuel does anyways (950psi air vs. 58psi liquid).

Robert56

iTrader: (2)

Ok, I see what you mean, good idea, control both out going fuel and nitrous noid from the get go with post FPSS.
Robert

DuronClocker

iTrader: (25)

Well, the pre-solenoid FPSS would control the entire system, just as normal. If a fuel pressure drop occurs, everything is shut-down as usual.

The post-solenoid FPSS would only control the N2O solenoid. Really, there is no need for it to control the fuel solenoid. If there isn't any flow after the fuel solenoid, there is no need to turn it off. Even if it is clogged and letting some fuel still (but not enough to make the post-solenoid FPSS enable the nitrous solenoid), worst case is you'll run a little rich.

The post solenoid FPSS would only control the nitrous solenoid. If the fuel solenoid is flowing properly, the nitrous solenoid will be activated. If the fuel solenoid is not flowing properly, the nitrous solenoid will not be activated.

lak8

Danm yea, i think that would work great. Only problem i can see with this is a little rich at frist but.... like you say the N20 is at what 900+psi and fuel maybe 50psi so it probably wont even be a problem. Even now that i think of it i bet a standard wet setup is super lean for the split second when the nitrous is activated.

DuronClocker

iTrader: (25)

Exactly my thinking behind this idea. If you have 18" of line to your nozzles (I realize not everybody does, just saying), and both solenoids open at the same time. I imagine the gas at 950psi will get to the nozzle a bit before the liquid at 50-60psi. This setup kind of makes up for that, as well as providing an added layer of safety in case of fuel solenoid failure.

lak8

some one should make a wright up on this and make it a sticky. I think this would be a very good saftey method when using nitrous. Im going to do this once i install my nitrous kit in the summer.

lak8

Something i was thinking of that might go wrong is... how long does it take for a FPSS to sence pressure and turn on (or maybe someone knows how long it take to sence no pressure and turn off).

This may be a problem since if it takes about 2sec or more it would be dumping in fuel with out the n20. this will couse a super rich situation and might get a intake backfire. If it senses pressure instantly i cant see a flaw in this DuronClocker and i think it would only help out more since im almost sure n2o reaches the nozzle before the fuel (this would probably be a split second but still) and this would be a big saftey feature in saving your engine from a faulty fuel noid not opening.

DuronClocker

iTrader: (25)

Yeah, I believe I mentioned that in one of my first posts in this thread that they may not react quick enough. If I didn't, I meant to as it was one of the first things that popped into my head.

I also noticed in a few threads where people said their AFR at the initial hit was 12.9-13.1, but leveled out at 12.5-12.6. So it seems like the nitrous does in fact get there before the fuel does normally.

We need to know how quick these sensors react. Anyone want to go out and test it? Floor the car and hit the ARM switch once you're already WOT and see how instant the nitrous hits. If it feels pretty instant, then there shouldn't be a flaw in this design. If it feels like there is lag time between hitting the ARM switch and the nitrous actually activating, then this idea will not work without a more complicated (and expensive!) time delay setup.