nitrous help

prairiehotrodder

Pro Stocker
Dec 17, 2005
1,576
4
38
46
Melfort Saskatchewan Canada
i don't think I'm gaining the power i should from my nitrous system. i'm running a nitrousworks kit that goes up to 200 hp but i switched to a NOS cheater plate because i damaged the threads on my NW plate. Since i'm running the cheater plate put in the supplied 180hp jets. On a full pass i went from 125 mph to 133 mph on the bottle. According to the hp/weight/speed calculator on the pro-systems website I am only gaining 100 hp. I emailed NOS about this and they said i should run equal size nitrous and fuel jets. Does this sound reasonable? I don't want to hurt my motor by leaning it out. I'm also tempted to get the cheater solenoids then run the 250 shot. I'd really like to break into the 9's. my car runs 10.8 on the motor and i thought the 180 shot would be enough but i only dropped to 10.4. I'm running a holley black pump to feed evrything and i'm also woried that it won't be enough but it hasn't given me any problems yet.
any ideas?
Brian
 

buschmec

Amateur Racer
Jul 7, 2003
214
0
0
panama city florida
actually you will probably end up with the fuel jet being 5-12 sizes smaller than the no2 to get the tune-up correct, you have to get the timing out of the engine (more than you think)........as for the cheater solenoids, the no2 oriface on the solenoid is only big enough to flow a 175 jet (.082) effectively......you need to do some research on lean vs. rich hurting pistons, you will find that 99% of all motors are hurt from rich conditions, very few are leaned out enough to hurt a piston and that is usually caused by timing not fuel curve.....
 

James Bond

Dragway Regular
Dec 26, 2005
1,359
0
0
Earth
What fuel pressure is the system at? At the typical 5.5psi a squared jetting will still be too rich. As bushmec said you'll end up quite a few fuel jet sizes under the nos jet. You'll see a significant power gain when the fuel said is tuned with the same nos jet size.
 

prairiehotrodder

Pro Stocker
Thread starter
Dec 17, 2005
1,576
4
38
46
Melfort Saskatchewan Canada
I've recently been told that the proper way to set fuel pressure is with the lines unhooked from the carb and nos plate and run into a jug, then turn on the fuel pump and set the fuel pressure at the regulator with the fuel flowing. I've never done this before. I just set mine at idle and i noticed that everytime i looked at my fuel press. gages the pressure was too high. Does this sound reasonable? I think on my nos passes my pressure may have been up to like 9 psi on my nos system. Also i have a msd timing computer set to take out timing when the spray comes on, i had it set to take out 6 degrees for a 180 shot from a total of 33 down to 27. Is this ok?
Brian
 

James Bond

Dragway Regular
Dec 26, 2005
1,359
0
0
Earth
You should have a separate reg for the nos system. Flowing it into a bucket to set the reg is correct but it needs go thru fuel jet that your going to use. Set it for 5.5psi flowing thru your nos fuel jet. The amount of timing you're pulling out sounds good but I can't comment on the total.
 

foureyed

Amateur Racer
Apr 6, 2012
124
0
0
janesville,wi 53548
James Bond said:
You should have a separate reg for the nos system. Flowing it into a bucket to set the reg is correct but it needs go thru fuel jet that your going to use. Set it for 5.5psi flowing thru your nos fuel jet. The amount of timing you're pulling out sounds good but I can't comment on the total.




Not true!! U should have a diff reg but all u have to do is pull the fuel line from the plate side and run it in a bucket.I wouldn't go less than 6 psi to start without tuning it at the track. If your total timing on motor running optimal is 33 then u want to take out 7 degrees for 180hp. 9psi is running u way rich. U should pick up 6-8 tenths off a 180 shot. Are u running colder plugs? They should be at least 2 steps colder.as far as pill size consult with your local nitrous guru.u can pm me if u have specific q's and I have 2 pro's that help me. They have cars ranging from 11.00 to 6.50 1/4 mile cars that they tune. I run a 534 w a hundo shot into the 10.40's.11.3 on motor.
 

junk racing

Amateur Racer
i got a nx dual stage plate kit that will make that car fly. set fuel pressure flowing at 6 psi, check bottle pressure 900-1100 is where i liked it. put 2 steps colder plug in the car and with good gas i start pulling timing after 100 shot. For example on my car when it had nitrous i had a 200 shot i pulled out 4 degrees total on 200 shot. 2 degrees is only a starting point every motor is different in what it wants.
 

Ed Cannon

Pro Stocker
Jul 17, 2009
1,682
0
0
Johnson City Tn
Your getting high pressure readings because your dead heading the fuel pressure against the fuel solenoid. A complete separate fuel system is the way to go. Get a good flow check tool there not cheap. Also invest in a fuel pressure cut off switch and install it before the regulator.
 

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