i'm hooking up a single nozzle dry kit and all i need to be finished is a fuel pressure safety switch. i've got a few questioins.

1. Will the switch screw right into my fuel rail after i remove the shrader valve or will it require an adapter?

2. Is the rev limiter a fuel cut or ignition cut type.(does the rev limiter take away fuel to keep the engine from over reving?)

thanks for your help. i'd like to make it to the track thursday and search isn't working.

 

Factory rev limiter cuts fuel so don't hit it under n2o. For my LS1 I use the Timing Tuner controller to cut power to the nitrous solenoid before the factory rev limiter can come into play.

My FPSS has a pipe fitting - 1/16th NPT I believe. I didn't / wouldn't attach it to the fuel rail. Rather, I have a -4 AN hose that goes into a distribution block for the fuel pressure gauge, fpss and fuel solenoid.

I have a wet kit on my LT1 pictured here but I don't think those differences should matter for what you want with your LS1 application. It is better to have a single hose off the fuel rail to a block, Y, Tee or series of Tees so no more weight than necessary hangs on the rail.

 

/\ Well he's going dry, so putting it on the fuel rail isn't that big of a deal. I've got my fuel pressure guage on the passenger side rail and no leaks, it's not that heavy. I would put the fpss on the passenger side fuel rail, no adapter required.
The rev limiter cuts the ingnition to a cyclinder (changing between cyclinders) until the engine rpms drops below the limiter. I would sudjest a window switch on your set-up if you don't already have one.

 

If you get a FPSS with a manifold it will screw directly into it, with the manifold connecting to the fuel rail (FPSS are usually 1/8" NPT). If you are using a flow through style manifold you'll need a AN cap to install on the other end, or fuel will shoot out.



Matt

 

/\ I've got a million of those little caps.

 

thanks guys especialy for the pics.

 

You're welcome but because there are contradicting claims within the replies, you need to find out for sure about how the factory rev limiter works as it's rather critical whether it is fuel or spark that gets cut: http://www.go-fast.org/z28/new_to_nitrous.html Look under SAFETY > IGNITION RPM LIMITER

I agree that an RPM window switch is an important part of nitrous safety, especially with a manual shift. Matt is correct about the 1/8" NPT for the fpss. I went out to my car with verniers in hand to verify. When I made my distribution block I remember that I had to use a larger pipe tap in one location, thinking I went from 1/16 to 1/8. I actually went from 1/8 to 3/8 for the swivel union between the zex nmu and the block.

As for the fuel pressure gauge on the end of the fuel rail, I have seen that done on other cars. 1CRAZY6 is right in that the gauge isn't very heavy. The LS1 fuel rail schrader connection is fairly strong on the LS1 but I took no chances with my LT1. Replacing the fuel rail for that engine is expensive. That is why the advice about using a fuel line and the caution against stressing that connection with any more weight than necessary. I'm sure there are thousands of LS1s with a Y, Tee or gauge attached directly to the rail. It's just a little more money to have a line from the schrader to one of these connections so that's what I have done. Also, I chose electronic pressure gauges in my A pillar. I can't watch fuel pressure at WOT otherwise.