You will not be happy for long with just a 50-75 shot for long, just start off with 100 pills, I like the Sniper kit from NOS, its good to 150 & thats all you will need on a stock short block, If tuned right it'll knock of a solid 1.5 sceonds & up to 13-15 MPH, The main things you will need to keep things safe. You can get away with just the T off on a 125 shot, But, you need a good pump like the Carter street/strip pump, you will need to run a reg. with this pump, It can put out a solid 9-10 lbs. pressure, I know some will say run a seperate fuel line for the Nitrous, its really not needed on a 125, especially the NOS kit, there on the richer end for safety, You really need to set the pressure flowing through the plate, not just an open line because it will be higher once hooked up going through the thin bar & spray holes. You really don't need to get very technical on a 125 shot, It will be fine, These are the upgrades i would do anyways as a given, Now once you start useing the 150 pills thats when its times to up-grade to a cell or sump the tank & run a seperate line & reg.
1. Get a good ignition system with an easy adjustable dist. so you can pull timing & curve it in.
2. Get a better fuel pump.
3. Run plugs 1 step colder & tighten the gap setting to .030", I step colder from stock is all thats needed for a 125, I really like NGKs V gap, they are easy to read.
4. On a 125 pull about 4-5* timing, then adj. up-down 1 deg. at a time untill you get the best MPH
5. Being new to this i wouldn't start messing around with the set chart pills, just stay with the chart.
6. Get a cowl mounted gauge so you can monitor pressure at all times, You can run a shut off for the Nitrous if the pressure drops below a set pressure, but i've heard they are not always accurate & tend to acted up.
7. If you can buy a Y fitting that would be better then a T, Just run the main line from the pump up to the Y & branch off to the carb/Noid, I would set the pressure at no more then 6 lbs. for both'
8. You can run an in line pressure gauge right before the carb, set the pressure, then run it WOT on motor & see how it does, if it stay fairly steady at 6 lbs., you'll be fine opening up the nitrous, the gauge may blurp abruptly but regain control quick (thats fine), it really won't drop that much on a 125.
9. Put you a brass fitting at the inlet of the carb main line so you can install the under hood gauge & run the line for the main cowl gauge.
10. You should be fine on Pump Premium fuel.
There are a few other things i thought about but i'm drawing a blank, If i think of them i'll add it in.
I ran the Sniper on my last Dart i had, I used the 125 pills & set the timing at 28* total, ran 1 step colder plugs, Used the T, had an elec. pump thats wasn't that steady (didn't know it at the time because i didn't have a cowl mounted gauge yet hmmmm), On motor car ran 8.3s @ 82- 83 that night on 1.90 60 fts.:angry7:, the weather was pucky, it normally ran consistant 1.80 60fts & 8.0s @ 85-86, On the 125 pills & pressure drifting from 5-6.5 lbs. this is what it ran with no i'll affects.
1.75 60ft. from 1.90, 7.48 @ 95 from 8.3s @ 84 & i had to abruptly lift do to drifting in the other lane, I went back 3 weeks later looking for that 7.2 pass, It was on its game that night, 8.09/8.13 @ 84-85 on 1.81s, I couldn't get any traction at all off the line :disgust:, but the car still gained 11-12 MPH on every pass, I ran the 1/8 most of the time.
BTW, this was on a 95 junkyard 360 magnum block with cast pistons, bolt-ons & small re-ground cam, kepped the shifts at 5100, 3.73 gears, 11" 2800 stall, My goal was 7.0s @ 99 on 175 pills.