mazgtr

Hi,

can someone help me with what size jets = a 50 shot?

I got a NoS brand wet EFI kit
powershot solenoid with 10 pound bottle

Doc Holiday

iTrader: (2)

Call the NOS tech line. They will tell you the jetting.

scathcart

What fuel pressure? What bottle pressure? You want that in flywheel or wheel hp? What engine? What turbo?
Answer these and I'll give you a better answer.


(taken from public profile) 87TII at full stock boost (5.5 psi) would be ~44 psi fuel pressure, with NOS's recommended bottle pressure of 900 psi, single fogger wet, putting down ~50 hp to the tires:

Nitrous: #37
Fuel: #22-#23 (start with 23 and tune from there)

mazgtr

Hey! Thanks
actually

13BT street ported (pinned)
cut rotors


42-44 PSI pressure is right
42PSI with one pump when the second on comes on
hits 44-45 PSI

plans for debut in early 2006

Precision GT42-74mm 22-25 PSI
T4 flange 1.15 A/R
Precision 850HP series intercooler
4" DP/Exhaust

going to need a good 50 (to the wheels)
shot to spool up this monster
in 3rd and 4rth

LUPE

50 shot
35 nitrous
24 fuel

75 shot
41 nitrous
28 fuel


This has been tested and works. (Steve Kan)

scathcart

My jettings have been tested and work.

I've got those jettings similar to both of those tested in my spreadsheet. Granted, this was on an N/A, but that won't change much. Using 950 psi of bottle pressure, 40 psi fuel pressure, those jettings won't make their jetted power, and they will run in the 10.5-10.8 AFR range... way too rich for nitrous in my opinion.

Example:
For a 35 nitrous jet at 40 psi and 950 psi, NOS reccomends a 20fuel jet. They reccommend a 24 fuel jet at 80 flywheel hp (42 nitrous jet).
For a 37 jet they reccomend a 21 fuel. I reccomend a 23 (at 950 psi bottle, 40 psi fuel), and usually tuning down to a 22. This will make almost exactly 50 hp to the tires.

For a 35 jet (50 flywheel hp), I would size a 22 jet and tune from there.

I consider my jettings fairly conservative for fuelling. A lot of managing nitrous safely comes from what you do with timing, epsecially on the trailing. I'm yet to lose a motor under juice, even pushing over 300hp shots.

mwatson184

NOS recomendations do not consider the fact that the air is pressurized in front of the nozzle. If you are running 5 psi of boost, and 40psi of fuel pressure, it is the same as running no boost with 35 psi of fuel pressure as far as fuel flow goes.

-Marques

scathcart

Which is why we run manifold referenced FPR's.

Every psi of boost increases the fuel pressure by one psi.
At no boost, (static fuel pressure), we should be around 40 psi. At 10 psi of boost, we should be around 50 psi of fuel pressure. At 20 inches of vacuum, we should be around 30 psi of fuel pressure.
Its about keeping a constant pressure differential of 40 psi between the fuel rails and the intake manifold... 40-45 psi differential with our setup gives optimum fuel atomization. Lower fuel pressures, and the fuel just dribbles out. Higher fuel pressures, and we just end up spraying the intake runner wal.

mwatson184

Ah, I must have misread the first time around. I didn't know you were asking for his static fuel pressure.

I think that statement is where I got mixed up.
-Marques