NOS Big Shot # 02102

Got a ? for anybody that may know,
the system is brand new, & the "old" jetting chart that came with the system looks like this:

 N2O...................fuel..................... HP
  82                       91                      225
  93                       102                    275
  102                     110                    325
  120                     116                    350+


New jetting chart says (Holley website)

 N2O................... fuel ...................  hp               
   73                     67                       190
   82                     76                       225
   95                     85                       275
   102                   95                       300

I have ordered a new pack of jets that reflect this chart.
but I want to know if anybody would have a HP estimate on a

  N2O...................... fuel ............. hp???    
    91                        82

fuel pressure 5.5-6 lbs
total time 32*   with  11* pulled out when systems come on.

Close to a real 250 shot from what we have done.

I would run less fuel pressure and less timing to start if it was gas but don't know what to do with alky.

Id run more spread with the 91n, like 15. Id do 5.5 psi fp also.

Id pull 13 degrees to start. Plug reading is a bitch w alky.

Kind of splitting hairs here.  Smaller fuel jet and more fuel pressure or same fuel jet and less pressure.  Either way is fine to an extent.  As long as you're flowing the proper ratios of fuel to nitrous I've never been concerned with the process.  

Example: We don't run bigger than a 32 fuel on our x275 foggers but have run over a 60 nitrous side.  Just add more pressure to get the correct ratios.  Now if we run the same car in a limited class such as a 36 nitrous side then we'll switch out the fuel side.



But as Jon and others have said before, too fat and/or over-timed is a lot worse than the other way most times.

"As long as you're flowing the proper ratios of fuel to nitrous I've never been concerned with the process."

not understanding this, are the "charts" not proper ratios???

the 10-15 jet spread seems to be the consensus from everyone, along with the 5.5 lbs of fp.

I understand the timing needs to be decreased more with bigger shots but I would think a total of 19-20 * when system is activated is good.

Is a 15 spread general rule of thumb on the higher HP ??

BTW this is a dedicated fuel system for the NO2 ( c-16)
and injected alky on the motor

Thats whats nice about having a system flowed by Steve, Monty etc..... it will come with jetting thats damn close out of the box.

any system is gonna need fine tuning, buy lots of plugs and sneak up on it slow....... again with alky in the mix its gonna make it hard to read the plugs....... Imo if your gonna spray it hard it might be time to swap it back to a good gas carb and run a good niitrous fuel.


I know the path your taking, Ive been there and done that. Anything under "200" wont be a big deal but anything over that w alky inj is gonna be tricky and the alky holds it back imo.

You might wanna rethink your camshaft too iirc its on the small side for a lot of spray.

Jon, never really intended to run spray with this motor, & cam is small ... period..... have another cam thats a little bigger ( .810) with a bit more duration & 112 lobe seperation.
just want about 190-200 maybe 225 if I need it to get me to that 1000 hp mark.
just did'nt want to go to all the expense of a GOOD carb & I really like the injection .

Thats what I said lol. Fixing to head to the shop and finish wiring the stuff for fogger number 2.

Your car is light it may respond better than mine did.

As Jon said, there is no real chart for this but experience.  The big boys have flow benches to figure out what the system really flows.  There is no magic jet spread or fuel pressure.  Some run low fuel pressure like the Steve Johnson and monte smith systems and some run high pressure like nitrous express.  People make nitrous tuning a lot harder than it has to be from what I see at the track.  Sneak up on the tune and good luck.  You will eventually switch back to gas after get get addicted to the spray.   

It's already been said that your cam is probably too small for much nitrous already.  About a 200-225 is all your motor will really respond to without a change.  But you'll love it.

whatbumper wrote:As Jon said, there is no real chart for this but experience.  The big boys have flow benches to figure out what the system really flows.  There is no magic jet spread or fuel pressure.  Some run low fuel pressure like the Steve Johnson and monte smith systems and some run high pressure like nitrous express.  People make nitrous tuning a lot harder than it has to be from what I see at the track.  Sneak up on the tune and good luck.  You will eventually switch back to gas after get get addicted to the spray.   

It's already been said that your cam is probably too small for much nitrous already.  About a 200-225 is all your motor will really respond to without a change.  But you'll love it.

Whats a good rule to go by on cam selection for a nitrous deal but still run good N/A

69bluehotrod wrote:

whatbumper wrote:As Jon said, there is no real chart for this but experience.  The big boys have flow benches to figure out what the system really flows.  There is no magic jet spread or fuel pressure.  Some run low fuel pressure like the Steve Johnson and monte smith systems and some run high pressure like nitrous express.  People make nitrous tuning a lot harder than it has to be from what I see at the track.  Sneak up on the tune and good luck.  You will eventually switch back to gas after get get addicted to the spray.   

It's already been said that your cam is probably too small for much nitrous already.  About a 200-225 is all your motor will really respond to without a change.  But you'll love it.

Whats a good rule to go by on cam selection for a nitrous deal but still run good N/A

It will always be a compromise. I would say a 110LS would be close. I will leave it at that.