Regulator vac/pressure port?

[jjump59]

Just about done with the XFI/Aeromotive A1000/Rick's stealth tank install, mounted my return style regulator by the tank and am wondering about the vac port on it. Do I need to run a steel line from the intake to the back of the car and hook it to the regulator? Can I just leave it open without connecting anything to it? Thanks

[Blown353]

Just leave it open, but I'd suggest putting a little filter on the end of it to keep junk out of it.

Capping it off will result in fuel pressure increasing as the regulator heats up and therefore the air trapped on top the diaphragm will expand from the temperature change. (think PV = nRT)

Running a vacuum line that long back to the regulator will result in very "lazy" regulator response especially during periods of fast manifold vacuum changes because the signal going back to the regulator will effectively delayed due to the length of the line. That will cause issues with the tuning.