NOS jetting

I believe there is a consensus by the quick running nitrous guys that the standard NOS jetting charts are bass ackwards - way too fat. I myself have been running a slightly leaned up standard-type tune on my ride and although I've had success so far just like most I want to run harder (and safer). I am looking for the more experienced guys to assemble a NOS/fuel/fuel pressure/timing charts for both plate & fogger to attempt to organize these tune ups. I realize that every ride is different and you have to meticulously watch plugs, ect. to get things spot on. But I think the gurus could point those of us seeking knowledge closer to enlightenment than those sloppy rich NOS charts. Thoughts?

Actually Holley has changed their jetting. If you notice they have changed to much leaner baselines. for example a 225HP tuneup used to be 82n/91f ans now its 82n/76f @ 6lbs fuel and 950psi N2O.

Really? I have yet to see this. Can you post it up here or a link?

http://www.holley.com/data/Products/Technical/A5061-1-SNOS.pdf
This is for a Big Shot plate. If you go to your specific part # it will have a instruction PDF for your kit.

Looks good. Seems to have a 6 jet spread with the larger NOS jet and more reasonable timing adjustment. This is more in line with what I have read on the forums for their tune ups. Thanks for the heads up!

NP, these jetting maps are alot closer than the pig fat tuneups of the past.

Sorry to drag up an old thread but want to start spraying a bit. I see holley have updated for thier big shot kit, but all their smaller kits still seem to have the fat tune ups. Can anyone give a good starting point for the smaller kits and tunes i.e super powershot and sniper @100 and say 125ish. I do realise you need to watch your plugs closely but rather than starting way out I would just like to have an initial tune thats not way out.
Thanks for any help given.

In many cases depending on the flow of the system around a .052 nitrous jet will flow about 100-125 HP worth of nitrous. As for a fuel jet if you start even .008 to .010 smaller at around 6 PSI you should be in the ball park.. Thanks, SJ

Thanks Steve

austin460 wrote:Thanks Steve

No problem.. Good luck.. SJ

I remember way back in ancient times when the old NOS Cheater 125, 175, 225 16 hole plate kit had a 225 jetting of 110/110, but the small passages in the nitrous solenoid were supposedly only somewhere around the .090" range.

DILLIGASDAVE wrote:I remember way back in ancient times when the old NOS Cheater 125, 175, 225 16 hole plate kit had a 225 jetting of 110/110, but the small passages in the nitrous solenoid were supposedly only somewhere around the .090" range.

we've ran that tune a bunch. of course not with 6psi. we flowed the fuel volume/weight rather than pressure. now we use wide jet spreads and adjust fuel pressure to compensate. of course now having a better understanding of stoichiometry helps.

Question or two for the nitrous guys out there,I am running a elderbrock performer nitrous system my jets are  nos 120/120 ,plugs look good about what x-tra hp is this giving me. Shooting for a x-tra 150 hp, I will be replacing the solenoids over the winter with some bigger ones .Thanks Dave
Just looked at the nitrous booklet that came with the system it calls for 57 nos and 65 gas for a 100hp gain should I go back to a more square set up like the 65's for a better performance.

120/120? Id think that would make ashtrays

after looking at some other post and checking more on the system that is on the car and looking at the jets I figured that was WAY to big for my system.That is why I'm thinking more around 65's to 70's range? WANTED to make sure it was getting fuel and nitrous  

i ran a 75n 60 fuel with those noids and a bigshot style plate on the sb car last fall, it was around a 175 shot and rocked on that 306 deal.....

I've got the 65 jet and thinking of drilling out one of the smaller jets to a 70 whatever drill bit number that is and try it,this is on a elderbrock performer plate also and on a 545 pump gas motor. I have it on a 4 degree retard chip will change it to 5 or 6 degree, motor is set at 34 degree total without nitrous on

buy some jets

looking into that also but thinking of buying a new system for winter upgrade and a few other things [ coating headers to get heat down] long winters here in ohio. NOTHING like what is happen out west. I hate FcKiNG winter:

Jets are the same for most kits. Pull more timing too especially if your spraying on pump gas

tfsbbf466 wrote:Jets are the same for most kits. Pull more timing too especially if your spraying on pump gas

. There are a couple of styles of jets so be sure to get the right ones if you do decide to buy.

Yea when I was at Norwalk this past weekend talk to so people from speed tech and they adviced me of the same thing about the jets,
guess I'll wait  to see which direction I go with this nitrous system that I'm running now. Only one more race this weekend.

dave d wrote:I've got the 65 jet and thinking of drilling out one of the smaller jets to a 70 whatever drill bit number that is and try it,this is on a elderbrock performer plate also and on a 545 pump gas motor. I have it on a 4 degree retard chip will change it to 5 or 6 degree, motor is set at 34 degree total without nitrous on

                                                                                                                                    Same as above, do not drill jets. There are two major reasons, at least, NOT TO, and it most likely will bite you in athe A$$ sooner or later. Not worth it, in my view.

these are the tunes Monty gave me a cpuple ago at drag week 65n 52f 5.5fp 28* total timing.... ive sprayed that tune a lot without trouble cast piston and all