I'm sure this has been asked before. I tried a search and didn't come up with much. So I'm planning out a progressive dry direct port system on a FAST LSXR manifold. The car is a C4 Vette and the under hood temps are very high because of the limited airflow on those cars. So I was debating installing the nitrous solenoid inside the car and running a 6an line from it to a Y and it feeding distribution blocks on each side of the intake. Would this work? Any downsides of having that much distance between the solenoid and the nozzles?

Also is there any issue with leaving pressure on the solenoid all the time. Years ago I used a purge to vent off pressure but it seems like a waste of nitrous.

 

You will have a softer hit the further the solenoid is away from the nozzles. Most direct port systems are going to have two nitrous solenoids, and it is fine to have them where they would normally be, on the intake manifold.

Leaving nitrous pressure on the solenoids will definitely damage them over time, it is best to close the bottle and purge the line out after a run.