BBF nitrous??s HELP.

I have a 466 BBF with ported to the max procomp aluminum heads and all the good stuff in them, Comp Cam 306-306
262-262 @.050
Valve lift 640-640 1.7 Rocker arms. SpeedPro dome pistons, Hbeam rods BIG tube headers, 1150 Dom carb, 4000 or so stall, C4, in a fox body mustang coupe.

Took the car out with a little 150 shot and on a real bad pass on foot brake went a 10.40. Ran out of nitrous so went home. I put a NOS double cross bar big plate on the car and took it back out and everything working well it only went a 10.20 at at 130mph. on a 250 shot..??? I reset the timing etc. What are you guys setting your fuel pressures and timing on motor and on spray at? Im still learning as I go. What do i need to change/do to get this thing dialed in..?? Thanks guys!!
11.20 on motor, 3300 lbs with me in it 114 fuel 6lbs on nitrous side and 5.5 on motor side.

Welcome to the site your going to get hammered for the heads. There are a lot of good no2 guy on the site they will chime in soon.

I know I am.. But it should not be that way. Im doing what I can with what I got.. Im willing to listen and learn.. Thanks

Looks like it runs good for what it is with that cam and heads. I dont think a nos tune will make up for it.....the heads being the biggest cork.

thxs for cking us out Jeremiah .... we are here to help you out and lets see what we can do with what you got


what rear end gear are you running ? and tire size ?

so when you run it n/a what is your timing set at ?

what jets are you using in the plate ?

also have you looked at the plugs after a run ? ... they will tell you alot about your tune ..

and if you get a chance on Monday give Steve @ I-S a call he wil help you out with a tune for you engine program .... you will be amazed

here is his # 815-341-8853


later
Nick

what comp ratio? what rpm leaving? stall?

Jeremiah wrote:I have a 466 BBF with ported to the max procomp aluminum heads and all the good stuff in them, Comp Cam 306-306
262-262 @.050
Valve lift 640-640 1.7 Rocker arms. SpeedPro dome pistons, Hbeam rods BIG tube headers, 1150 Dom carb, 4000 or so stall, C4, in a fox body mustang coupe.

Took the car out with a little 150 shot and on a real bad pass on foot brake went a 10.40. Ran out of nitrous so went home. I put a NOS dubble cross bar big plate on the car and took it back out and everything working well it only went a 10.20 at at 130mph. on a 250 shot..??? I reset the timing etc. What are you guys setting your fuel pressures and timing on motor and on spray at? Im still learning as I go. What do i need to change/do to get this thing dialed in..?? Thanks guys!!
11.20 on motor, 3300 lbs with me in it 114 fuel 6lbs on nitrous side and 5.5 on motor side.

its running out of fuel

Leaving at about 3000 or so... What makes you think im running out of fuel? Its not falling on its face or anything... 411 with 28/10 tire going threw thw traps at around 6700 6800..

The plate is jetted 44 on the nitrous and 45 on the fuel double-cross bar plate...

BOSS 429 wrote:

Jeremiah wrote:I have a 466 BBF with ported to the max procomp aluminum heads and all the good stuff in them, Comp Cam 306-306
262-262 @.050
Valve lift 640-640 1.7 Rocker arms. SpeedPro dome pistons, Hbeam rods BIG tube headers, 1150 Dom carb, 4000 or so stall, C4, in a fox body mustang coupe.

Took the car out with a little 150 shot and on a real bad pass on foot brake went a 10.40. Ran out of nitrous so went home. I put a NOS dubble cross bar big plate on the car and took it back out and everything working well it only went a 10.20 at at 130mph. on a 250 shot..??? I reset the timing etc. What are you guys setting your fuel pressures and timing on motor and on spray at? Im still learning as I go. What do i need to change/do to get this thing dialed in..?? Thanks guys!!
11.20 on motor, 3300 lbs with me in it 114 fuel 6lbs on nitrous side and 5.5 on motor side.

its running out of fuel

the fuel presser you run isnt even enought to seat the float seats, 6 on nos too little

Jeremiah wrote:The plate is jetted 44 on the nitrous and 45 on the fuel double-cross bar plate...

Jeremiah,

i will let Steve chime in on this but i believe that jetting on that double crossbar is incorrect ...way too rich ...

i dont want to start to give out tunes , because im no were the expert on this stuff but im thinking 65/61 @ 6lbs and the bottle pressure @ 950 .... for the 250 shot ....... and Steve will also help with you timing #s also..... what noids do you have with the systems ?

and what plugs are you using ?

p.s. also all the old nos tunes are incorrect and they have been corrected recently most of them were way to rich !!

That might be the prob.. I have been going by the book that came with the kit.. It has the big noids.. help me out... Where can I find some better jetting #s?? 65/61 might be a 250 shot on a single bar plate.. But its a little different on the double cross bar plate..

Think I got it figured out.. we looked up nitrous jetting for the dubble cross bar and I guess it HAS been updated.... With 44-45 jetting I was only spraying maybe a 150 shot again... For a 225 shot its calling for 51 nitrous and 61 fuel... I put the 44s and 45s in by the book I got with the kit. SO I dont know what the prob is there..??? So everything I am doing so far is correct for me to be in the 9s. Just have to get the right jets in it.. LOL!

Any good jetting charts to go off of? What fuel pressures and timing should I run with the 250 shot??

Your tune is too rich. I would pull the plugs from that run and see how your fuel looked, and where the timing mark is. If your going from a 150 - 250 I would cool the plug off 1 step and start conservative w/ the timing I.E pull 8-10 degress from what it ran best on motor. Baseline the fuel @ 6psi. Its hard to recommend a total timing or deadset jet recommendation without seeing what the plug is saying.

Sorry for the delays in getting a look at this..

Seems there's a few things that are still questions ??

Compression ratio, Chamber size in head, cam lobe seperation, base timing, amount you retarded for each tune, what size jet were you flowing thru, hows the fuel system set up, to name a few..

Just like the others were saying about the jetting, the near squared jetting is pretty rich and the returns are as good as when the system is flowed and set up with a proper nitrous to fuel ratio and HP settings. We have blueprinted and flowed quite a few of those systems as well, to get the nitrous to fuel ratios correct will take quite a bit larger nitrous jet the fuel depending on the nitrous solenoid size, fuel solenoid size, bottle supply and so on...

Hope this helps.. SJ

Well be giving you a call in the next day or so steve.. Thanks!!

You need to know where the timimg is and the fuel pressure or you will be carrying it home in a basket. Check the plugs on ever pass until you get a good tune up. Good luck and go fast!

I think im pretty close.. But going to call steve and see what he says.

Looks like were pretty close.. THANKS FOR YOUR TIME STEVE!

Your welcome.. Just remember to take it slow as there are many variables on all this.. Yell if you need anything else.. Thanks, SJ