nos pills

meat1037 · Member Joined: 24 Mar 2008 Posts: 36 1241.38 points

Could anyone tell me what pill to use to make a 75 shot i have the sniper system for chevy carburetor.

af2 · Posted: Wed Apr 02, 2008 10:31 pm Post subject: Re: nos pills

10sec.et · Posted: Wed Apr 02, 2008 10:37 pm Post subject:

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.

Big Dave · Posted: Thu Apr 03, 2008 5:08 pm Post subject:

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

SMOKEmUP · Posted: Mon Apr 07, 2008 7:47 am Post subject:

That's interesting the fuel jet doesn't change from 50 - 100 HP.

wagon train · Posted: Wed Apr 09, 2008 3:45 pm Post subject:

clay · Posted: Wed Apr 09, 2008 7:15 pm Post subject:

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

GrandSportC3 · Posted: Tue Apr 15, 2008 9:00 am Post subject:

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

GrandSportC3 · Posted: Tue Apr 15, 2008 9:06 am Post subject:

William Jones · Posted: Tue Apr 15, 2008 9:07 am Post subject:

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

GrandSportC3 · Posted: Tue Apr 15, 2008 9:21 am Post subject:

pro60chevy · Member Joined: 01 Jan 2004 Posts: 406 16.00 points

Paul P · Posted: Fri Aug 08, 2008 12:53 pm Post subject:

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.

Skunkworkx · Posted: Fri Aug 08, 2008 4:01 pm Post subject:

Every Mfg. is different.... use what the maker of your kit recommends !

Paul P · Posted: Fri Aug 08, 2008 8:56 pm Post subject:

Yes and recommended fuel pressure is a big item not to miss besides jetting.