fuel pressure for nitrous...

-
bad440

bad440

everything,all the time..
Joined
Mar 27, 2010
Messages
3,646
Reaction score
177
Location
oakland ca
heres the thing,want to start small,have 47n 36f jets.going to run 5 psi of fuel to fuel solinoid.have a press reg and it goes to gas sol.put a gauge on it and itwill bottom the gauge out over 15 psi.i only have one fuel pump 18 psi electric.sumped tank 1/2 inch fuel line to dash 8 to split then to both reg.the carb i have set at 7 pounds .the other wont regulate down.reg is good works ifyou switch them.whycant i get the press down to the fuel sol?
 
i'm not real sure what you mean as I hadn't had any coffee yet. maybe a pic would do it. I'm sure 7lbs is too much for either the carb and the nos. run the carb at no more than 6lbs and the nos at 5-6lbs. you might consider upping the gas jet to around a 41 or 42. an eleven step difference seems kind of lean. are you flowing the gas through the jet? do you have two separate regulators? check out the pics, see how the nos has it's own regulators for each stage and the motor has it's own.
 

Attachments

  • older Pictures 277.jpg
    84.7 KB · Views: 256
  • older Pictures 327.jpg
    104.3 KB · Views: 283
  • older Pictures 285.jpg
    98.1 KB · Views: 258
Is that 7lbs with the solenoid open and fuel flowing? That's how you should be setting the nitrous fuel pressure. I take the plate off and stick it ina 5gal bucket...
 
If you swap regulators, does the other regulator do the same thing, max the gauge out? I'd question the gauge at that point.

If you have 11 step stagger, run 6 psi to the fuel solenoid to start would be my approach.
 
no need to take the plate off to wet flow the kit. take the braided hose off regulator that goes to the plate. get you a #3 an union. and modify it to hold you fuel jet that looks just like the fitting in your plate. point that hose with the fuel jet you are using into a fuel jug. ok now, not sure how you will be using your NOS. but turn on all your electrical accessories on that will be used during a run. electric fans,electric water pump and all fuel pumps you will use. be sure and not have a battery charger on either. then activate your nitrous kit so fuel flows thru your line out the jet and set your regulator to 5-3/4 psi on your gauge. and always use the same gauge for all your adjustments. not all gauges will read exactly the same.
 
With the "Holley" style regulators, you have to set them with fuel flowing. With the fuel not flowing, the regulators tend to get pressure creap.
PS: with the numbers you gave, I think you will be too lean.
With a fuel pressure of 6 PSI, nitrous bottle pressure of 950 PSI, nitrous jet of .047, you should use a fuel jet about .043. That will give you just about 100 hp engine.
 
Steve Smith Blue printed my NOS system.
And according to him pick your fuel Pressure and then your n2o pressure.
I had to send him my fuel pump.regulators and the complete nos system including the intake and he will drill out the jets for your hp settings.
I had him do my Zex plate and the direct port system.
A lot of misconception that you have to run 1100 lbs of n20 pressure.
Whats real important is to have the same n2o pressure down the hole strip.
I ran 2-20 lb bottles when I use to run both kits.
This is just my ramblings.
Just remember stability with fuel and n20 pressure is always your friend.
 
I have 3 kits on my 7 second car. A 350 shot and two other 300's. Each regulator has and quick connector on it. And I use the big speedtech gauge to check fuel pressure with a orfice equaling the diameter of each fuel jet added up. I run 8 spread. And my fuel pressure does best at about 5.25 psi on each stage. If you font have race pack. Check your plugs often. Nitrous is safe, if your very careful and stick to the rules.
 
moper said:
Is that 7lbs with the solenoid open and fuel flowing? That's how you should be setting the nitrous fuel pressure. I take the plate off and stick it ina 5gal bucket...
Click to expand...

With all due respect, this is not helpful advice. This is not accurate.
 
SpareParts said:
With all due respect, this is not helpful advice. This is not accurate.
Click to expand...

That is the way I have always done it and it has always worked for me. I used 47n and 53f most of the time. I picked up at least 7 tenths in the 1/8 mile. 7.20's to 6.40's. It varied because of traction issues. 5.5 lbs fuel pressure.
 
D-50394 said:
That is the way I have always done it and it has always worked for me. I used 47n and 53f most of the time. I picked up at least 7 tenths in the 1/8 mile. 7.20's to 6.40's. It varied because of traction issues. 5.5 lbs fuel pressure.
Click to expand...

I think you should read over what I quoted then read what you posted. They are two different things therefore you saying "that's how I do it" then claiming you use a different fuel pressure (7>5.5) does not make sense.
You don't flow a kit through the plate or even through the solenoid. You don't even need to activate the kit to flow it. I learned my ways from a pro and use over 100lbs a season, I'm not just posting because I like moving my fingers.
 
SpareParts said:
I think you should read over what I quoted then read what you posted. They are two different things therefore you saying "that's how I do it" then claiming you use a different fuel pressure (7>5.5) does not make sense.
You don't flow a kit through the plate or even through the solenoid. You don't even need to activate the kit to flow it. I learned my ways from a pro and use over 100lbs a season, I'm not just posting because I like moving my fingers.
Click to expand...

What I was saying is I take the plate off the intake and set the fuel pressure to 5.5 lbs while spraying the fuel through the plate with the jet I am using. I have done it that way for at least 18 years and never killed a part. I did not say it was the correct way.
 
I got ya. The message got a lil lost in there. All you need to do is right out of the regulator through a 73 jet or a Holley 70 jet which measures .073. Don't bother with the solenoid or plate and use a high quality accurate gauge. Thumb up!
 
You must log in or register to reply here.
-

Back
Top