soundengineer

iTrader: (16)

Just looking for the Math..the actual calculation values.. not just pointing me to an online calc...
I have a bunch of different jets and want to see every possible combination I have and I'm planning on making a spreadsheet.

plus I can post it here to help others once I get it all done.

Thanks.

cncbird

iTrader: (3)

You have to flow it through the system to get the actual flow.The same jet can get different flow depending on solenoids,line size and lenght, and bottle valves.

soundengineer

iTrader: (16)

yeah yeah...blah blah blah
I'm asking for the math to get me in the ballpark....
not for exact science here..

looking for the math used in most of the online calculators...
looking for math for the Nitrous jets, and then math for fuel jets
with variables for Nitrous pressure and fuel pressure.

I think I have found the Math for the Nitrous Jets....
Jet size(usually listed in inches) - Convert it to mm....squared.... *70
gets me a rough estimate of added HP per Port.

But I have no idea how to get my fuel jets based on Fuel pressure and Nitrous pressures.
none of the online calculators seem to show the HP being effected by the Nitrous pressure...which I find odd seeing how it should be directly related to it.

Gary Z

A rule of thumb for calculating horsepower as a function of jet size is
hp = (JetDiameter)^2 x 70
jetDiameter in millimeters
This formula assumes nitrous oxide @ bottle pressure of 800 psi
Reference: Nitrous Oxide Performance Handbook by Jeff Hartman

soundengineer

iTrader: (16)

yeah.. I found that one..
My question becomes... what about the fact that its considered ideal to be around 950ish

then what...

how does bottle pressure affect that formula....
and what affect does fuel pressure have on the Fuel Jet sizes as well...
and how do I calculate an appropriate starting point fuel jet for my N20 Jet?

is there a rule of thumb?

Like I know that with a bottle pressure of 1000psi and a fuel pressure around 55psi, a .047/.025 is supposed to be a good starting point for a 100HP shot.

Graham@NitrousOutlet

If you are trying to get a starting point for the setup in your signature, I highly suggest you do not use a formula and have the system flowed. Two stages and that amount of nitrous is pretty easy to hurt parts.

soundengineer

iTrader: (16)

I havent even started on my own car yet...lol
i still have to upgrade my fuel system before i go doing my big direct port.

i just have a bunch of jets laying around... want to know what they are-ish

Also im helping some other people out...

I know a small handful of values that work...
on a plate kit...
I know a rear wheel 200 is a .071/.036 ish jetting
while just a straight engine 200 shot is just a .066/.034

Just trying to figure out what the rest of my jets will do.

Graham@NitrousOutlet

Who's Plate? Who's solenoids? How many 90* fittings? What bottle valve? What size main feedline?

78N/46F is 200hp on our plate system at stock LS fuel pressure. Just trying to let you know a formula will not give you jetting, it might get you somewhat close.

soundengineer

iTrader: (16)

ugh......
why is this so dam hard for people to understand....
Using math to get a starting point...
If I throw in a .066 Nitrous jet.. I want to know the math to get the approprite ballpark fuel jet so I'm not way rich or way lean
LS1...55-58psi at the rails
approx 900-1000 at the bottle..

helping out a buddy... trying to get a good starting point and we'll change fuel jets from there...

If he decides to go with a bigger Nitrous Jet, then I want to have a starting point for his fuel jet....

I'm the guy who is going to be tuning it... I just dont want to start way off for the first pull on the dyno.

camscam02

iTrader: (21)

you just don't understand do you? There is no formula that works for every thing.

To get exact numbers for your kit you need to flow your plate both nitrous and fuel numbers in lbs/hour or however you collect the information. The info I dont know is how much pounds per hour through a certain jet makes 50/100/150 hp.

Then for fuel jets you use flow of both nitrous and fuel and go for a targeted Nitrous/Fuel (N/F) Ratio. somewhere between 8:1 etc. Everybody has there preferences and it has gone from a richer ratio to a leaner ratio now a days.

That would be how jetting is configured for a specific system and what will happen give or take when you have a system flowed and jetted

These are general hp for most though.

52-100
57-125
62-150
67-175
72-200
77-225
82-250
87-275
92-300

Those are very very general but something to go by. Hope that helps

ATVracr

iTrader: (5)

Some people dont get that there is no easy answer or magic formula.

soundengineer

iTrader: (16)

ok.. how about this...
Buddy has a Nitrouos Express Plate Kit.
were going to start with a .066 Nitrous Jet and work our way up trying to get to a 200 rear wheel hp shot

what fuel jet should I start with

1 right angle on the back of the nitrous solenoid and 1 on the back of the fuel solenoid
4an lines everywhere...


somebody give me a good starting point for his fuel jet for a .066 Nitrous Jet...
its an LS1 Fbody built for nitrous.

ATVracr

iTrader: (5)

The right plug and timing numbers will help alot.
Just take it slow, its hard to hurt a built motor with 150 shot.

Your 66n/34f should be close enough to make a 1/8th mile hit, check plugs from there.

Good luck!

soundengineer

iTrader: (16)

Its going to be a day of pulls on the dyno till we get to his goal..
I'll adjust fuel jets as we go... but I wanted a starting point
Tuning with a wideband, logging Lambda in HP Tuners

he will eventually end up with a 250 hit at the track.. but he's going to keep it at a 200 for the street

Graham@NitrousOutlet

Math, wideband, and a dyno for nitrous tuning?

While you clearly have a handle on this I would just like to add this is not how I would go about this. I would step back and try and see how the guys that are going fast are doing. Truly, best of luck and I hope for the best. Keep us up to date.

ShiznityZ28

iTrader: (11)

This ends well....

87silverbullet

iTrader: (11)

No it won't.

I did the "spraying on the dyno thing" and I also have the carnage to prove it too. Don't worry ATV gave me a good enough beating about it but 4 spun rod bearings, 2 spun mains and a bent crank was enough of a punishment to me.

The dyno will let you put a good amount of timing back in and then when you go to the track

Graham@NitrousOutlet

Very sorry for the loss but glad you posted. I know it is not as convenient as 3 pulls on Saturday afternoon, but plug reading at the track is simply the nature of the beast with Nitrous. Some get away with not doing it, but that is exactly what is happening, they are getting away with it.

I would say well over half the times I ask what the plugs look like... I get this:

"Fine."

87silverbullet

iTrader: (11)

To get a lil more in depth of my dyno day. I was able to shoot a 200 on your 2 stage plate on pump gas with only pulling 5* from 28 total. I made 3 pulls and showed no detonation. I went to the track and my buddy was driving. I was standing at mid track and I could hear the detonation. My buddy never let off until he could hear the rods knocking which was at about 900ft. He coasted to a 10.68

So lesson learned here was to ask questions about spraying and then spray, not to spray and then ask questions about why my bearings look like this.