Schrader Valve Pressure

[darebren]

please look at the pic below. the black bike tube pressure looking thingy with a blue dot on it is the fuel rail schrader valve.

Has anyone put a guage on this to see what the fuel pressure is? there is also one on the passengers side, and then this one is on the drivers side at the end run of the fuel rail.. I wonder if it gets at least 38psi??

I have a kit to hook my NOS fuel line into this valve, but the instructions call for using the one on the passenger side rail... I don't know if there is a difference, but using the drivers side one will make my install much cleaner... see my gallery!

[MENINBLK]

The fuel enters the rail on the passenger side.
The valve on the driver's side is at the end of the rail.
If the NOS kit require full pressure 100% of the time then you need to use the pass side schrader valve.
Pressure will fluctuate at the end of the rail after 8 injectors have tapped from it.
You need to be plugged in where the fuel enters the rail.

[TripleTransAm]

Most likely, yes above 38 psi.

About which side to use... could it be that your kit is made for the 4.6l DOHC applications where the intake faces the passenger side, and hence it's 'cleaner' to use that valve? You could always call the manufacturer to get the inside scoop on why they specify a given side.

On some of the older multi-port FI engines, fuel pressure could vary *slightly* based on where you checked it. This was because of the order in which the injectors firing, which could affect line pressure at the fuel rails, and hence some sort of equalization crossover was required along with careful attention to where the fuel pressure regulator was located.

In our application, there is no fuel return line, so I would imagine the pressures are equal across all branches of the fuel rail system. But like I said, you're best off consulting with the kit producers...

[darebren]

sometimes a phone is pretty helpful.. with email and this site, I'm not used to the phone anymore.. but in this case. ZEX said that in a pressurized system like ours with no return line, and tap in point along the fuel rail will have more than enough pressure for the NOS kit.