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meat1037 Member
Joined: 24 Mar 2008 Posts: 36
1241.38 points
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Posted: Wed Apr 02, 2008 8:54 pm Post subject: nos pills |
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Could anyone tell me what pill to use to make a 75 shot i have the sniper system for chevy carburetor. |
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af2 Member

Joined: 01 Sep 2003 Posts: 5568 Location: grassvalley, ca 71528.86 points
1933 Willys Coupe
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Posted: Wed Apr 02, 2008 10:31 pm Post subject: Re: nos pills |
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meat1037 wrote: | Could anyone tell me what pill to use to make a 75 shot i have the sniper system for chevy carburetor. |
Meat, hay before the horse.  |
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10sec.et Member

Joined: 29 Mar 2006 Posts: 3483 Location: Houston,Texas 347040.52 points
1969 Oldsmobile Cutlass
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Posted: Wed Apr 02, 2008 10:37 pm Post subject: |
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i dont have a spec for a 75 hp plate system. according to one of my books, the 100 hp is N2O .047 FUEL .053. it seems that every .008 size larger on the N2O is worth 25 hp. the fuel is not so consistent. be careful with that. sorry i cant be more help. _________________
af2 wrote: | It seems we can look at our magical Balls and come up with a fix?
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Big Dave Moderator

Joined: 04 Dec 2005 Posts: 2660 Location: Tampa Florida 120444.52 points
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Posted: Thu Apr 03, 2008 5:08 pm Post subject: |
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Nitrous has to operate at about 900 to 950 psi at 85° F in the bottle (bigger bottles are used not because you can burn more NOS but to keep the system pressure stable). You will need at least 93 octane fuel to run up to 100 horse of NOS. Anything beyond that and I recommend a fuel cell filled with 100+ octane fuel just for the NOS system. Remember the power comes from the fuel not the NOS so you have to have enough fuel to cover your NOS shot or it will find something else to burn (like pistons). Your fuel pump and fuel lines have to be up to the task (volume and pressure must be adequate. As to jet sizes (measured in thousands of an inch) they are listed on Holley’s Tech Support site as follows:
Horse ….. NOS ….. Fuel
50 HP ….. 0.032" … 0.042"
60 HP ….. 0.034" … 0.042"
70 HP ….. 0.036" … 0.042"
85 HP ….. 0.045" … 0.042"
100 HP … 0.055" … 0.042"
150 HP .... 0.070" … 0.053"
Spark plugs shouldn’t have more than a 0.035" gap (most modern car engines run projected nose plugs with gaps of 0.060") so you will need a reduced nose plug in the correct heat range for your motor to keep out of detonation. To be safe pull out two degrees of ignition advance for every 100 horse of NOS.
Big Dave |
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SMOKEmUP PostMaster

Joined: 30 May 2002 Posts: 3171
65149.84 points
1979 Chevrolet Camaro
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Posted: Mon Apr 07, 2008 7:47 am Post subject: |
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That's interesting the fuel jet doesn't change from 50 - 100 HP. _________________ Stop running from your pain and embrace your pain. Your pain is going to be a part of your prize.
I challenge you to push yourself. |
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wagon train Member

Joined: 07 Jun 2007 Posts: 258 Location: Orange City, FL 7307.16 points
1983 Mercury Capri
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Posted: Wed Apr 09, 2008 3:45 pm Post subject: |
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Big Dave wrote: | Nitrous has to operate at about 900 to 950 psi at 85° F in the bottle (bigger bottles are used not because you can burn more NOS but to keep the system pressure stable). You will need at least 93 octane fuel to run up to 100 horse of NOS. Anything beyond that and I recommend a fuel cell filled with 100+ octane fuel just for the NOS system. Remember the power comes from the fuel not the NOS so you have to have enough fuel to cover your NOS shot or it will find something else to burn (like pistons). Your fuel pump and fuel lines have to be up to the task (volume and pressure must be adequate. As to jet sizes (measured in thousands of an inch) they are listed on Holley’s Tech Support site as follows:
Horse ….. NOS ….. Fuel
50 HP ….. 0.032" … 0.042"
60 HP ….. 0.034" … 0.042"
70 HP ….. 0.036" … 0.042"
85 HP ….. 0.045" … 0.042"
100 HP … 0.055" … 0.042"
150 HP .... 0.070" … 0.053"
Spark plugs shouldn’t have more than a 0.035" gap (most modern car engines run projected nose plugs with gaps of 0.060") so you will need a reduced nose plug in the correct heat range for your motor to keep out of detonation. To be safe pull out two degrees of ignition advance for every 100 horse of NOS.
Big Dave |
What is the fuel pressure for those tune ups.NOS tuneups are different. _________________ FORD POWER RULES DEATH TO ALL CHEVYS.
"BAKER"
10/5/50-11/7/06
"She doesn't seem to be breathing right,it might be the jets."-The Mechanic |
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clay Moderator

Joined: 24 Nov 2002 Posts: 3209 Location: South Carolina 318129.23 points
1972 Chevrolet Nova
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Posted: Wed Apr 09, 2008 7:15 pm Post subject: |
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I remembered something I had that may be useful. However is a pdf file and I'll need some help getting in somewhere everybody can see it. I found it about a year ago and I have no clue where I found it or what the link is. HELP!!! Clay |
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GrandSportC3 Moderator

Joined: 11 Jul 2003 Posts: 1231 Location: Lakeland, FL 32443.62 points
1968 Chevrolet Corvette
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Posted: Tue Apr 15, 2008 9:00 am Post subject: |
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Nitrous jetting seems to vary based on what system you are using..
My Edelbrock kit calls for:
HP/nitrous/fuel
50/38/44
75/46/51
100/57/63
150/71/75
200/85/89
250/104/108
The fuel side is always 4 - 6 jet sizes above the nitrous side for my kit
Fuel pressure for the system is supposed to be between 6.5 and 7 psi and bottle pressure between 900 and 950 psi
Timing needs to be retarded by 2 degrees for every 50 HP |
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GrandSportC3 Moderator

Joined: 11 Jul 2003 Posts: 1231 Location: Lakeland, FL 32443.62 points
1968 Chevrolet Corvette
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Posted: Tue Apr 15, 2008 9:06 am Post subject: |
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SMOKEmUP wrote: | That's interesting the fuel jet doesn't change from 50 - 100 HP. |
I can't imagine that the chart is correct.. I've never seen anybody use bigger nitrous than fuel jets unless you want to go BOOOOOOM!!! |
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William Jones Member

Joined: 30 Jan 2006 Posts: 823 Location: Lake city, FL 28541.86 points
1971 Ford Mustang
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Posted: Tue Apr 15, 2008 9:07 am Post subject: |
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What alot of people don't realize to is that the fuel pressure is suposed to be set under flowing conditions and measured after the soleniod. When you start getting close on the tune a 1/10 of pound means alot.
Bam _________________ Take the horse out off the barn and let her RUN BABY RUN!!!!!
92 LX 454ci Clevor 9.24@142.53 N/A
71 Mach1 454ci Clevor 10.16@134 N/A 3850lbs race weight "Lost in fire"
03 Cobra Bone stock 12.42
68 Falcon 363ci 10.55@126 N/A
95 GT 363ci 11.08@118 N/A |
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GrandSportC3 Moderator

Joined: 11 Jul 2003 Posts: 1231 Location: Lakeland, FL 32443.62 points
1968 Chevrolet Corvette
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Posted: Tue Apr 15, 2008 9:21 am Post subject: |
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William Jones wrote: | What alot of people don't realize to is that the fuel pressure is suposed to be set under flowing conditions and measured after the soleniod. When you start getting close on the tune a 1/10 of pound means alot.
Bam |
Very true!! I have a hose that I connect to the connector that is connected to the fuel solenoid. At the end of that hose I have a fitting that will accept nitrous jets. I install the nitrous jet that I'm running and then turn on the fuel pump and let the fuel flow into a container while I set the fuel pressure. I always use the fuel jet for the shot that I'm running.. So, if it's a 100 shot, I flow the fuel for the 63 jet, for the 150 with the 75 jet etc. etc.. |
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pro60chevy Member
Joined: 01 Jan 2004 Posts: 406
16.00 points
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Posted: Fri Aug 08, 2008 11:41 am Post subject: |
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GrandSportC3 wrote: | SMOKEmUP wrote: | That's interesting the fuel jet doesn't change from 50 - 100 HP. |
I can't imagine that the chart is correct.. I've never seen anybody use bigger nitrous than fuel jets unless you want to go BOOOOOOM!!! |
Not true on a fogger system, my fuel jets are 4 sizes smaller than the NOS jets, on both stages. |
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Paul P Member

Joined: 15 Aug 2002 Posts: 2436 Location: Townsend, Mass. 82671.86 points
1971 Chevrolet Chevelle
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Posted: Fri Aug 08, 2008 12:53 pm Post subject: |
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Here is some useful links for the first one you have to do the math to get inches for the jet sizes. The second one just enter the jet size and fuel pressure which is important to get the rest of the story quite nice!
http://www.nitrous.info/nitrous-fuel-jetting.htm
http://www.robietherobot.com/nitrousjetcalculator.htm
Nitrous jets are bigger than fuel generally in the second one and change a lot depending on your fuel pressure. _________________ 2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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Skunkworkx Member

Joined: 02 Sep 2007 Posts: 353 Location: Harford Co. Maryland 10348.44 points
1968 Chevrolet Camaro
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Posted: Fri Aug 08, 2008 4:01 pm Post subject: |
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Every Mfg. is different.... use what the maker of your kit recommends ! _________________ 68 Camaro LSx
AKA:RedЯum |
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Paul P Member

Joined: 15 Aug 2002 Posts: 2436 Location: Townsend, Mass. 82671.86 points
1971 Chevrolet Chevelle
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Posted: Fri Aug 08, 2008 8:56 pm Post subject: |
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Yes and recommended fuel pressure is a big item not to miss besides jetting. _________________ 2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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