holley blue fuel pump regulator

[Stainless1]

Scott, we were working with a 10 lb bottle with 11-12 in it.  When you hold the button for extended time, the bottle will get colder and the pressure will drop.  We tried to control that variable by keeping the bottle cold, not easy at Bonneville... then tuning for the cold bottle.  Again when I say tuning, we ran fuel and N20 through the individual injectors, making sure the flowed equally injector to injector and the total weight of fuel was compared to weight of N20.  Just pick numbers and stay consistent, look at bottle pressure, it indicates bottle temp.  Vary jets and pressures and you can tune it as close to the line as you want, but remember you can be rich and not lose much HP. 
When you ran it on the drag strip, how did the plug look?

[KZScott]

i never really did a plug chop and tow it back to the pits. I have my power commander map so that it dumps a bunch of fuel in at 0 % TPS at high rpm down to about 5000. i was told by a LSR/road racer guy this cools the pistons off. it would more than likely throw off a plug reading. so far Ive done tuning/monitoring with an Innovate LM-1. I try to run 12.8:1 AFR NA, and richer on spray, around 12:1