The way I had mine done was I had a bottle heater that weighed maybe 10oz. I wired it to a seperate switch that was on the dash. I would flip on the switch a few minutes before i was ready to start running it. I also mounted my pressure guage in the dash so i could see it at all times. On Sand Mtn UT which is about the same as NV, by the time I would coast back down the hill for another run, the pressure would be back up and ready for more. NX has a kit that will regulate your pressure by turning the heater on and off at preset points. Its a bit more spendy than a simple guage and switch but effective. Get your heater off of Ebay, cheapest place to find them and any of them will work.

After having mne I was to the point of where I didnt want a FTP switch. I would rather have a momentary switch on the handle bar that the NOS would be on only while pushing it. That way I could launch hard in first and the second I hit second gear I would bring on the NOS. I could not launch on the NOS even sitting on the gas tank. with your +4 it may be different but I dont think a +4 is enough. I was running a 15/43 gearing with 20" 8 paddles and it was simply too low. I think the stock gearing with 20's is about perfect for running NOS. I might have been able to shoot in first gear with that combo.

A delay would do you pretty much no good, your not runnning the same quartermile strip like a car would that the delay is desighned for. A progressive controller would work well but would take some tuning to get right. Pluss as stated it is a bit harder on your soleniods. I would experiment with gearing and switches before dropping $550.

What pluggs are you running and what fuel are you running as?

 

My 720 has stock swingarm with 20" 17paddle brats with fcr dual carbs. I have to clutch it out the hole in 2nd gear slow to say least!!!!!!!!

 

thanks for the help looking into a bottle heater already have a 42 rear sprocket and then 16 and 17 front sprockets so i'm sure i'll find a gearing that works, better. hope the swingarms works out i wouldn't really like a longer one. with the heater i'll get a more consistant run every time, probably only got 2 runs close to 25 hp then they slowly faded(still fun though) probably got a true 15 runs this time pretty nice i thought already ordered a new bottle.