[ItBites]

Everyone who has chimed in here is correct and you need another complete fuel supply circuit (pickup, pump, lines, regulator). This is almost always done when modified engines use nitrous also.

You should also consider a low fuel pressure - nitrous cutoff switch. These devices are available from NOS and others and can (but won't always) prevent a bad day.

Also: HPDrifter mentioned spark gap earlier. Listen to him, he is right. My PSCA buddies that run BIG nitrous have found they have to run gaps as small as .025 in order to get consistent firing. I have seen this to reduce ETs by over .5 seconds in back-to-back runs in those cars.