NOS and FAST

[dhegge]

Guys,

I have a twin-turbo small block 375CI motor that makes over 1000HP w/20PSI of boost. So I have already got a huge fuel system etc. I have temporarily removed the turbos from the car to combat some driveability issues. The motor still makes a shade over 500HP NA.

I was wondering what exactly would I need to do with my SFI fast system/84LB injectors, weldon pump, etc. to be able to use NOS? It would seem to me like a dry system would be fairly easy to construct. Is anyone using the FAST NOS control?

I don't think that I need a hole kit with fuel control etc. It seems that I need a bottle, lines, valves, nozzles and a TB plate? or am I missing something?

Also I am confused as to how many stages of NOS fast can control... the software seems to imply 3. the wiring diagram indicates two... another reference says that if you have IAC which I do... that you cannot use two stage NOS?

Craig/Lance whats up with the NOS? Thanks in advance.

P.S. evenutally the twin-turbos will be going back on the motor and the NOS will probably hang around as well. Geez 1200HP
NO Turbo LAG!

Doug

 

[bobc455]

Remember that getting HP from nitrous is somewhat different that getting HP from air. Normally air contains other inert things, and has a higher nitrogen content that N2O- this means that the oxygen from nitrous is more readily available, and you will have a quicker combustion that requires less timing.

Even if you are not on the verge of detonation, you might still make more HP by retarding the timing a bit extra.

You may consider doing a "manual" nitrous system- don't even tell the FAST that you are running nitrous, and just retard the area of the timing map where you'll be using it. However this might be better done with a wet system than a dry system. Or, make it think it's adding the nitrous (i.e. send the arming signal to the FAST) but keep the solenoid under your control with a pushbutton.

My opinion has been not to rely on the FAST to make corrections when using nitrous, personally I don't trust the WB readings when nitrous is around. This is easiest done with a wet system of course...

-Bob Cunningham

 

[Craig Smith]

A sequential system with IAC control won't have nitrous control outputs. This is one of the issues we are addressing with the new ECU design we are working on.

C-Com covers ALL applications. Some ECUs can control multiple nitrous stages, some can do one, and some don't do any. While ECU capabilities vary, we maintain a single version of C-Com that is capable of controlling all the functions of any particular ECU.

 

[DeltaT]

The way they do a 3-stage system with 2 wires is:

Stage One only
Stage Two only
Stage Three - Both together

I asked the same question looking at the schematic!


jim

 

[RickWI]

Since you have IAC, like I do, how the FAST can control nitrous is a moot point, since it can't. I did what Bob mentioned and installed the nitrous seperate from the FAST and I modify the spark map prior to hitting the button. For controling the nitrous hit I use a NX controller to bring in/stage the nitrous.

I use my existing fuel system by simply tapping in a T right by the fuel rail that then feeds the fuel spray bar, NX or others can provide this. My jetting specs are set for 39psi of pressure, injector pressure in other words. I have plenty of headroom on my pump to handle the extra fuel flow at that pressure. I also have a low pressure fuel switch wired into my nitrous system in case fuel pressure falls below 35 PSI.

Some parts I'd recommend, bottle heater, bottle pressure gauge, controller, WOT switch, low pressure fuel cutoff switch.

As for a dry system, I would never, ever think to do this.