i found this when i went looking for edelbrock nos jet sizes and i couldent find **** so can anyone here tell me if this program is on the level or off
heres a link for it:
http://www.robietherobot.com/NitrousJetCalculator.htm

 

Pretty much dead on for me.

I use a .047" nitrous jet, and a .036" fuel jet. with 13psi of fuel pressure, I picked up 88 RWHP. 209rwhp NA, 297rwhp nitrous.

Their calc for that nitrous jet shows a .035" I should probably be running that, or a .034" as I was rich on the WB readings. It shoudl I should pick up 84.8hp, which is almost dead nuts on.

 

COOL thanks for the reply, i have a edelbrock wet kit and it dosent say what hp the jets are....now knowing it just about on i can install on the motor and now worry about it ****ting because of the wrong fuel jet

 

Hopefully that is the same for edelbrock, it should be close though. My jetting is on a NOS kit.

 

Dewey,
Is that with the jetting that NOS recommended for your kit or what you ended up with for best power. I compared this with the NOS recommendations for the 5151 kit (TPI) and it was off quite a bit. I know that NOS jets rich for safety but it was off by a pretty big margin. Basically the calculator said that I should use .025 fuel jets with my .046 N2O jets (before I get corrected remember that I have the older kit and it uses two jets fuel, two jets N2O).

That means the calculator recommends a fuel jet size .003 smaller than the jetting recommended for the 110 shot with the N2O jets for the 150 shot. Maybe there is something to that since I went pig fat on the dyno last year.

I would be interested to see other people chime in on this calculator.

-Schultzy

 

Yes, the numbers I am running where the ones holley gave me, since I was using my plate in an application it wasn't meant for, I had to ask what jetting to run.

I don't recall just how rich you were. You are also running higher than factory fuel pressure, which will affect your jet size also. I still think we should rent some dyno time, and get a whole slew of fuel jets together, and tune the nitrous on your car.

 

Hard to tell. The wide band on the dyno pegs at 10:1 AFR so probably > 10:1. Could certainly see it kill the power.

-Schultzy

 

So anyone reading this can have the full story.

Schultzy and I were talking online. The jetting NOS recomended for his TPI application, was the same I got from NOS for my TBI application. The diffrence is, I am running 13psi of fuel pressure, he is running 46.

I cannot figure out the Jetting NOS is giving out on the TPI kits. Maybe someone else can give more information, but the jetting info I can find on the 5151 kit, is no where near what it seems it should be.

 

Dewey is your setup a spraybar, single nozzle or dual nozzle? Just asking because I'm not familiar with the TBI setup.

 

My setup is a carb spray bar, since I run a 4bbl intake. It is basicly the super-powershot kit from NOS. I then rejetted according to the jet recomendations I got from NOS for my fuel pressure.

 

From reading the TPI kit instructions from NOS, they are figuring the stock fuel pump and counting on the fuel pressure dropping down once the solenoids energize. If you're running a better pump your jet sizes should be smaller.

 

That is what I got from them reading a copy of the instructions, also.

 

I called and talked to NOS, since I installed my Walbro 255lph pump I was running really rich with a 70 jet and a 38 in the fuel side. They recommended a 70 jet and between a 33 and a 35 for the 150 shot and a 30 to a 33 for the 125 shot. I ended up running a little leaner than what was recommended (28 jet fuel and a 61 jet nitrous) and haven't had a problem with it yet. I also tapped an NOS wet nozzle into my MAF sensor after the element and that made quite a bit of difference in how the car pulls, I am a believer now that the plate will starve the first 2 cylinders for nitro. With the Walbro pump installed and a new factory fuel pressure regulator I run around 49psi on the throttle and I'm hoping it's not dropping much pressure on the nitrous because the recommendations NOS gave me were for 49 psi constant pressure. The guy from NOS also said that at this high of fuel pressure there's not alot of variation on the fuel side from shot to shot as can be seen by the 125 vs 150 recommendations.

 

That jetting sounds a lot closer to what I would have expected. Seeing the jetting recomendations in the NOS documentation, would make your CRAZY rich, if you are running a constant 40psi +.

 

I have just bought a NOS plate system (05151). I have also installed a 255/lph intank fuel pump. Should I run the suggested 55-42 jets to my 305 for a 100hp shot or should i go smaller?

 

Smaller, NOS recommended a 30 to 33 jet on my setup, if you want to be cautious you can run a 35 or 37 jet; I would recommend replacing your regulator first, they're avaliable at Auto Zone for 30 dollars and some change, also check your fuel pressure, mine runs 45psi at idle 49 at WOT.

 

I just got my first nos set up..wet kit
it was used..
it has a 70 jet for the fuel and a 49 for the nos.

I have a stock 305 ci tpi I-Roc.

any one tell me a safe jet setting?

and what the hp would be gained with this set up?

I cant even get the car out of the shop now to much snow.

 

I would swap the 70 jet to the nitrous side and the 49 jet to the fuel. This will give you right at a 150 shot. This would be the highest I'de go on a 305. If you want to step down a bit get a .058 and a .037 jet.