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Re: NOS jetting (pill) question
[Re: Mr.Yuck]
#1380869
02/03/13 06:16 PM
02/03/13 06:16 PM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
master
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master
Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
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That is about a 100 HP. Pull at least 4 degrees timing as 38 is a touch high. Start with 5 psi fuel pressure to the fuel soleniod. If it pops on top end add a little fuel pressure.
Leon
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: NOS jetting (pill) question
[Re: Mr.Yuck]
#1380871
02/03/13 06:52 PM
02/03/13 06:52 PM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
master
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master
Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
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Yes that is too much. Add a regulator for the nitrous. That is the #1 tuning tool.
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: NOS jetting (pill) question
[Re: Leon441]
#1380872
02/03/13 07:21 PM
02/03/13 07:21 PM
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Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
ProStDodge
master
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master
Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
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As Leon sort of eluded to, the HP and fuel mixture you get with the jets is dependent on your fuel pressure DURING THE RUN.
Static pressure may not reflect the actual flowing pressure. So giving a set of pill numbers to someone may or may not provide the desired results, depending on their fuel system capabilities.
If you run a separate fuel system with a tank up front, you are more likely to have a constant fuel pressure to the plates than if you simply tee off a line from the carb fuel supply.
In your case, you are only trying to deal with 100-150 HP so it may not be as critical as if you were adding 400HP of NOS, but even at 100HP you can lean a motor out if the fuel pressure drops too much.
Your jets - N34 - F32 at 6.5 lbs of fuel pressure and assuming 900psi bottle pressure, should provide 94hp with a N/F ratio of 5.2 I like to keep the N/F ratio between 5-7. (under 5 getting too rich, and over 7 getting too lean). At 7.5psi fuel pressure you have 102HP, but N/F ratio drops to 4.83.
If the fuel pressure during the run is 4.5 lbs, the same jets are now calculated at 79HP and the motor gets leaner with a N/F ratio of 6.2 (in the middle of the "safe" zone).
The same jets at 9 lbs of fuel pressure could give you about 112HP, but starts to get overly rich - a N/F ratio of 4.4.
With 4 jets (2 N & 2 F) and a known fuel system, I would probably run N38 F34 for a 100hp shot. With an unknown system, I would error on the safe side with a N38 F36
For the 150hp range, N46 F44 (for unknown fuel system) and N46 F42 if I knew I could count on 5.5 lbs of fuel.
Of course NOS bottle pressure also plays into the mixture formula. I base most of my calculations around 900PSI of bottle pressure, which should be close when the bottle temperature is about 80 degrees. Heating the bottle over 80 gives you a higher pressure, which will lean out you N/F mixture.
During the run, the bottle will cool from the start to finish, which will give you a richer mixture at the end of the run than at the starting line. (This is a lot more critical in a 400hp system than in a 100 to 150 HP system.) I generally have my bottle pressure about 950 before the purge. It will drop a little after the purge, giving me about 925psi at launch. After a 10 sec pass, the pressure is usually about 875psi, so I base my calculations on the average which would be 900.
I would like to see the timing closer to 34 degrees with the 100hp set up (as Leon suggested), and 32 if you use the 150HP setup.
There are a lot of variables in a NOS system, but with a little common sense, it can be a lot of fun and still safe for your motor.
Scott
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Re: NOS jetting (pill) question
[Re: Mr.Yuck]
#1380874
02/03/13 09:28 PM
02/03/13 09:28 PM
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Joined: Jul 2010
Posts: 1,491
Oologah, Oklahoma
Big Squeeze
pro stock
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pro stock
Joined: Jul 2010
Posts: 1,491
Oologah, Oklahoma
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Wow....IMHO, that's way too complicated...  ...and figuring HP off fuel jets and pressure does not work...it would be like figuring HP off what jets you have in your carb.... IMHO, people make this way too complicated....Here's how I explain it to people....the nitrous jet is how much power you could potentially make and you use the fuel jet to to richen or lean it out until it makes the most HP for that nitrous jet...just like a naturally aspirated motor, it pumps an X amount of air through it (nitrous jet) and it's our job as tuners to change the carb jetting (or fuel jet) to get the most HP out of our naturally aspirated motor.... When you go up on nitrous jet, you will naturally move more air and make more power just like going up on cubic inches or more cylinder head will naturally move more air and make more power in a naturally aspirated motor... So, all you have to do is pick a nitrous jet for how much power you want and then keep leaning it out until it stops gaining trap speed....ANYTHING you do that makes more trap speed means it was the right direction to go...(just like naturally aspirated tuning)..... Having said that....they key to consistent results and being able to even bracket race with nitrous is to keep the bottle temp consistent every pass....the best way is to use a water bath set to 100*....and purge to 950lbs before you stage..... Now, the kicker is timing which gives a lot of people a hard time...ALL you have to do is keep it out of detonation...so, if it were me, I'd start out at 28* with a 100 shot and 25* on a 150 shot....then lean it out 2 numbers at a time until it stops gaining trap speed....then AFTER that, add 1* at a time until it stops gaining trap speed....(again, this is exactly the same process as tuning n/a because, after all, even though you're spraying, it's still just an n/a motor)... Most everyone knows that if the air gets better we need to pull a degree or two of timing while tuning a naturally aspirated motor...and if the air gets better, we're realistically only picking up 5-15HP....now imagine the air got so much better that we actually picked up 100hp...How much timing would you have to pull then?...any time the oxygen content in the air is higher, we have to remove timing because oxygen is an accelerant and that's the reason we don't spray pure oxygen...   Also, changing the flowing fuel pressure is a VERY SMALL tuning move..Moving the fuel pressure 1 pound would be like changing you n/a carb jetting 1 number....and if you were in the high 10 a/f ratio moving one jet size smaller wouldn't do very much... If you have an O2 sensor and your car runs the best around 12.5 to 1 A/F, just keep leaning it out until it reads in the mid 12's on spray....even if you're spraying in Denver or at Atco, just change the fuel jetting to be in the mid 12's...(just make sure to pull a few degrees of timing when going to Atco!!).. It's really that simple... 
If you can't handle the truth, you're living a lie.......
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Re: NOS jetting (pill) question
[Re: Big Squeeze]
#1380877
02/03/13 11:10 PM
02/03/13 11:10 PM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
OP
Not enough dumb comments...yet
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OP
Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
Quote:
that doesn't sound that simple really... lol boost was much easier.
What's hard?
Pick a nitrous jet for the hp you want...
Start out with timing conservative...
Make sure bottle temp is 950* or you have 950lbs of pressure...
Lean it out until it stops gaining trap speed...
Put timing into it 1* at a time until it stops gaining trap speed...
That's all there is to it...
There is only one thing that will hurt a motor.....Detontation.....What causes it? It's always one or a combination of three things....
Too much timing for the burn rate you have....
Too low of an octane for the cylinder pressure you have....
Or oil getting into the combustion process which lowers the octane....
That's it....
octane shouldn't be a problem. I'm running a snow Performace Meth/H2O injection kit. It's under the center carb and sprays at WOT. I guess I should have mentioned that.
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Re: NOS jetting (pill) question
[Re: Big Squeeze]
#1380879
02/04/13 03:15 AM
02/04/13 03:15 AM
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Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
ProStDodge
master
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master
Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
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Quote:
the nitrous jet is how much power you could potentially make and you use the fuel jet to to richen or lean it out until it makes the most HP for that nitrous jet...just like a naturally aspirated motor, it pumps an X amount of air through it (nitrous jet) and it's our job as tuners to change the carb jetting (or fuel jet) to get the most HP out of our naturally aspirated motor....
Sorry, but on this one point I will have to disagree. Nitrous does NOT make power. It can't, it doesn't burn. It does provide more oxygen so you can burn more fuel. But the amount of fuel you burn determines the amount of energy you make, not the amount of air you put in the cylinder.
And really, my numbers were easy to come up with. I just plugged in the desire HP and jet sizes, along with fuel pressure, and the Nitrous Master software program came up with everything else I need.
Nitrous Master
The software is not hard to use and I have done well tuning my cars and several others.
A friends had a car that ran 7.20 on motor(1/8-mile). He wanted to run a 6.40 heads up race. I calculated how much horse power was need to run the 7.20 at his race weight, and then how much horse power it would take to make the same weight go 6.40. Then used the Nitrous Master program to determine what settings were needed to get that much more HP. It worked out amazingly well. The car ran a 6.407 on the first pass with the NOS. Was I lucky? I don't know, but we too the same car to a Pink's all out. Ran 11.07 on motor. We decided the "class" was going to be closer to 10.30. I again calculated how much additional hp was needed to go from 11.07 to 10.30. Next pass out they sprayed the starting line with VHT right in front of him (first time they sprayed all day) and the car ran 10.20. I still say if the VHT was not added, he would have run 10.30.
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Re: NOS jetting (pill) question
[Re: ProStDodge]
#1380882
02/04/13 10:02 AM
02/04/13 10:02 AM
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Joined: Jul 2010
Posts: 1,491
Oologah, Oklahoma
Big Squeeze
pro stock
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pro stock
Joined: Jul 2010
Posts: 1,491
Oologah, Oklahoma
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Quote:
Quote:
the nitrous jet is how much power you could potentially make and you use the fuel jet to to richen or lean it out until it makes the most HP for that nitrous jet...just like a naturally aspirated motor, it pumps an X amount of air through it (nitrous jet) and it's our job as tuners to change the carb jetting (or fuel jet) to get the most HP out of our naturally aspirated motor....
Sorry, but on this one point I will have to disagree. Nitrous does NOT make power. It can't, it doesn't burn. It does provide more oxygen so you can burn more fuel. But the amount of fuel you burn determines the amount of energy you make, not the amount of air you put in the cylinder.
And really, my numbers were easy to come up with. I just plugged in the desire HP and jet sizes, along with fuel pressure, and the Nitrous Master software program came up with everything else I need.
Nitrous Master
The software is not hard to use and I have done well tuning my cars and several others.
A friends had a car that ran 7.20 on motor(1/8-mile). He wanted to run a 6.40 heads up race. I calculated how much horse power was need to run the 7.20 at his race weight, and then how much horse power it would take to make the same weight go 6.40. Then used the Nitrous Master program to determine what settings were needed to get that much more HP. It worked out amazingly well. The car ran a 6.407 on the first pass with the NOS. Was I lucky? I don't know, but we too the same car to a Pink's all out. Ran 11.07 on motor. We decided the "class" was going to be closer to 10.30. I again calculated how much additional hp was needed to go from 11.07 to 10.30. Next pass out they sprayed the starting line with VHT right in front of him (first time they sprayed all day) and the car ran 10.20. I still say if the VHT was not added, he would have run 10.30.
I, respectfully, disagree....We build naturally aspirated motors to move more air...we install bigger nitrous to add more air....when the DA goes down we get more air....everything we do is to get more air in and out...which is the EXACT same reason carburetors are rated in CFM and not GPM....if it was all about fuel, we could just keep adding more and more fuel jet, which obviously doesn't work...Nitrous hp numbers are derived off the nitrous jet, NOT the fuel jet, by every Nitrous company because, again, it's all about how much air you can move....
You can't use fuel to calculate HP because some motors are more efficient than others....if you have a 14 to 1 440" motor with quench and EFI that will zing to 7,500rpm and a 8.5 to 1 632" with no quench and a carb on top of Rat Roaster intake and hydraulic cam that will only go to 5,500rpm, the 632" will take a lot more fuel along with a 100hp nitrous jet to dial it in....
Ask anyone that builds race motors...the goal is to make as much hp as possible with as little fuel as possible...
If you can't handle the truth, you're living a lie.......
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Re: NOS jetting (pill) question
[Re: ProStDodge]
#1380883
02/04/13 10:05 AM
02/04/13 10:05 AM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
OP
Not enough dumb comments...yet
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OP
Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
|
Quote:
Quote:
the nitrous jet is how much power you could potentially make and you use the fuel jet to to richen or lean it out until it makes the most HP for that nitrous jet...just like a naturally aspirated motor, it pumps an X amount of air through it (nitrous jet) and it's our job as tuners to change the carb jetting (or fuel jet) to get the most HP out of our naturally aspirated motor....
Sorry, but on this one point I will have to disagree. Nitrous does NOT make power. It can't, it doesn't burn. It does provide more oxygen so you can burn more fuel. But the amount of fuel you burn determines the amount of energy you make, not the amount of air you put in the cylinder.
And really, my numbers were easy to come up with. I just plugged in the desire HP and jet sizes, along with fuel pressure, and the Nitrous Master software program came up with everything else I need.
Nitrous Master
The software is not hard to use and I have done well tuning my cars and several others.
A friends had a car that ran 7.20 on motor(1/8-mile). He wanted to run a 6.40 heads up race. I calculated how much horse power was need to run the 7.20 at his race weight, and then how much horse power it would take to make the same weight go 6.40. Then used the Nitrous Master program to determine what settings were needed to get that much more HP. It worked out amazingly well. The car ran a 6.407 on the first pass with the NOS. Was I lucky? I don't know, but we too the same car to a Pink's all out. Ran 11.07 on motor. We decided the "class" was going to be closer to 10.30. I again calculated how much additional hp was needed to go from 11.07 to 10.30. Next pass out they sprayed the starting line with VHT right in front of him (first time they sprayed all day) and the car ran 10.20. I still say if the VHT was not added, he would have run 10.30.
so how much of each do I need to run 10.40? Car should be around the 11.20 mark as is... Also Ron yes the meth/H2O will stay on... It's under the primary, the NOS goes under the outboards.
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Re: NOS jetting (pill) question
[Re: ProStDodge]
#1380885
02/04/13 10:51 AM
02/04/13 10:51 AM
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Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
ProStDodge
master
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master
Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
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Mr. yuck.
If you give me a time slip from a good run in your car on motor, the weight of the car, motor size, gear ratio, transmission type, stall speed, tire size, I will come up with a NOS setup that should put you in the 10.40's.
Scott
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Re: NOS jetting (pill) question
[Re: ProStDodge]
#1380886
02/04/13 11:13 AM
02/04/13 11:13 AM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
OP
Not enough dumb comments...yet
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OP
Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
|
Quote:
Mr. yuck.
If you give me a time slip from a good run in your car on motor, the weight of the car, motor size, gear ratio, transmission type, stall speed, tire size, I will come up with a NOS setup that should put you in the 10.40's.
Scott
Best run was 11.38 @ 118.35, 1.60/60ft, 7.30ish 1/8 (I think),that was with old slicks and 1 3/4" headers. Going to 2" and better slicks and rear shocks. I'm guessing motor only I'll be around 11.20 @ 119-120. Car weighs about 3800-3900.
Stock stroke 11.2:1 440-6, 727, 3800 Turbo Action, 3.91's, 275/60/15 drag radial. I also run the washer fluid injection under the primary carb. Should I even use that w/ the NOS? It does seem to help.
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lol. I'm going to print that out.
Hopefully if I'm wrong on this one of the more knowleable sages on here will straighten us both out 