Ok not sure if this will help or not, but I had drawing this out on another thread and thought it might need a lillte attention. I have not tested this in shape or form just drawn it out.


On another board someone mentioned this and I went and created this image. If something is wrong or needs to added let me. I will make changes and re submit.

Ricky

 

Pretty simple, seems like it should work.

The only problem I would see is if some how the fuel side FPSS got tripped but the nitrous side was still good say because a accumulator, it would still be safe cause you have fuel but it may cause some STRANGE surging.

 

Ricky, whats the purpose? To catch a defective fuel solenoid or to give a delay for the fuel lines to fill up and mount the sender at the end of the line? Looks good but you will get a delay off the line while the fuel pressure builds high enough to turn the Nitrous solenoid on. Ok, Here is a good idea for this. Make a Wide Open throttle switch
with two switch points. Trip the fuel solenoid at 1/2 throttle (fully adjustable) so the fuel starts every so slightly before the Nitrous kicks in at WOT. Guess this would not work well for transbrakes though?

 

You can change the activation point or "delay" of the second FPSS to trigger the nitrous noid by adjusting its set point. Could be anywhere from 5 psi all the way to 40 or anywhere in between. Seems like setting it up this way and then playing with the pressure setting on that second FPSS you should be able to dial out any lean spike you may encounter. I like it!!!. Thanks for the diagram Ricky.

I will be using the Maximizer...I doubt this would work for my setup with pulsed noids though. If I was doing a 200-300 or more direct port single stage I would definately give this dual FPSS a shot. its cheap and just requires a little extra time.

 

The purpose a person mentioned it on another board. So we I saw a simular discussion over on this board I deside to draw it. I the first fpss screws up and closes the fuel noid the second FPSS losses fuel pressure and will shut the nitrous noid down.
The reason kinda a hobby to draw wiring. Got about 80 or so pages of different things like this one.

With a transbrake just donot go all the way to the floor. Do you mean like this. It would take alot to get this type of set dialed in and then you would always be playing with the first switch.
One final note it would realy only work it a person just rolled into the throttle, I do not think it would work if you just stabed it.



Ricky

 

Here is a suggestion to make this even better. This is based on the first diagram. Remove the ground from the second FPSS and tap it into the white wire that goes between the first fpss and the fuel relay.

What this does is prevent the nitrous sol from staying on if the fuel sol flickers like it does if the first fpss is set too high. I have seen them flicker because the fuel pres drops when the sol opens, then the fpss shuts the sol, then pressure rises again etc,etc.
Now its even more fail-safe.

 

ttt,
Vinny

 

I like this idea. I think putting the second fpss as close to nozzle as possible is a good idea. Yes, this will probably make the lean spike worse, time wise, but you'll have the full fuel press at nozzle ready to go. To fix this we could add a digi timer to the n2o side and totally dial out the lean spike.

 

lean spikes worse?????????
This reduces lean spikes, by delaying the N20 Noid opening until the fuel sol has opened and pressureized the line.

 

Your right, I had two ideas going at once and it came out wrong. Yes lean spike gone if fpss is close to nozzle, eliminates lean spike. If it's it's at the noid then you still have the problem of the n2o getting there first, and thus the idea of the digi timer, eliminate lean spike.

 

Couldn't you just wire a Dynotune time delay switch to your signal wire on your nitrous relay?
That way you force the nitrous solenoid to wait until the fuel pressure stabilizes. And you can adjust it by .1 second intervals to get it just right...


*edit* Oops, 860 Performance beat me to the same conclusion...

 

Sure but you have to figure out the time delay. Same results, but lets say your fuel noid piston swells a little and now does not flow or slows the flow down,your time delay will click or open the nitrous noid anyway. With the drawing the nitrous noid can never fire until there is pressure inside the line after the fuel noid.
Ricky

 

So Ricky, would you say that mounting 2nd fpss as close to nozzle as possible would eliminate any lean spike? or would n2o still beat the fuel to cly? or at least minimize ant lean spike?

 

The 2nd fpss could be anywhere in the line, since hydraulicly saying both ends of that line should rise in pressure at the same time. But I would want it near the noid, easy to mount, and wire.
I will bet you will still see a lean spike, since you will have a pressure drop in the fuel rail until the line gets filled up. What this will allow is NO nitrous until your system is balanced at some pressure( depending on what fpss choosen.) Now there will be no way for the nitrous to get to the cylinder first since the fuel is already flowing and injecting waiting on the nitrous.
The graph should look, a little lean, then a little rich, and recover to a sweet point. Our dyno mule is down right now so I can not show a graph of this. Here a while back had a customer or forum memeber request it, so I drew it.
Ricky

 

I could be a dyno mule.

 

If the Timing Tuner from fullthrottlespeed.com had the ability to have two rpm window switches, it would solve this problem. I had a 383 Lingenfelter 1990 Corvette with lot s of juice....I used a Holley Strip Annhilator ignition box that had two rpm window switches. I used one on the N20 solenoid at 3000 rpm and the other on the fuel solenoid at 2800-2900 RPM. Worked perfect. Less cumbersome than the dual FPSS stuff I think.

 

Its not the same, your dual window switch dosen't know if the fuel noid opened.

This is a failsafe system, that emininates a lean condition from a stuck closed fuel solenoid.

 

Man this sounds good, like it should be standard issue. For the main benifit of safety, with the added kicker of minimizing lean spike.

 

excactly

 

I hope you do not intend to use the cheap NOS Hobbs pressure switches to try this. Ever tried to get one to repeat within 3 to 4 psi.... They wont. In my opinion you are going to introduce more problems into the system then worth the trouble. Now if you have found a reliable, repeatable switch to use.