Another nitrous question

[jwhitehead]

have a 502 with a fogger, timing set @ 36, retard set @ 12, 1050 dominator with 88 front and rear jets,everything new, set up 300 shot, bottle full with 900 p.s.i. engine back fires thru headers , shut engine down. Checked plugs, electrode in porcelin on some plugs had started to melt.

set up 250 shot increased bottle pressure to 1100 p.s.i. car ran 1.16 / 60 foot, 5.38 @ 127 mph.

SB2 406 small block ran this good, what am I missing?????

[bjuice]

You gotta run a cooler Plug..2 levels cooler then all motor plug,,you also need to close up the gap from 25/26...i have see Big inch NOS motors running 22 gaps.
also have you manually checked your timing retard to make sure its pulling the timing out when you pull the trigger? (critical)

Next how are you feeding the fuel to the motor and Nos ?..did you wet flow the Nos to make sure your fuel pressure is holding upon activation ?

No doubt you got some detonating going on there.



Brian

[jwhitehead]

I am running AR3933,.035 gap, fuel pressure is set @ 10 p.s.i. with fuel pump running and fuel flowing thru return line to cell.

Un sure about retard, was working with small block. will check.

[bjuice]

for starters you need to be running an AR3932 Plug and close that gap to 25 for starters.

Next have someone pull the trigger on the Nos ( just test the selenoid)..make sure Nos is not live nor fuel or Nos is dumped in motor.. while car is idling (3k) see if timing is being pulled out ( with timing light) when trigger is pulled...you will see it back up on the balancer.


i can tell you have not flowed the Nos by your post...thats ok many do not know how to properly flow a (wot) Free flow...i don't know if i can explain it good enough for you in a post...
What concerns me next is what kind of fuel pump you got supplying the Motor and Nos ?..then what kind of igintion you running ( crank trigger) ???

if your not running a BG 400 or Magnafuel Prostar 500 or some comparable fuel pump..chance are you don't have near enough pump to support a 300 shot on a 502 ( in one pump)...

my advise to you..is don't run any more NOS until you know for sure rthe things i have posted...youll burn that bad boy down in a skinny minute with a 250/300 shot..

there's alot more to running Nos Safely than what one thinks ?

[lookingaround]

i use to run a holley blue pump just for my NOS. when we set the pressure we set it on 3 or 5 pounds free flowing on a 250 shot. like Brian said go 2 steps colder on plug too. Brian is it 2 degree's timing retard for every 100 horse of NOS? its been since 98 since i have raced are used any

[hammertime]

i use to run a holley blue pump just for my NOS. when we set the pressure we set it on 3 or 5 pounds free flowing on a 250 shot. like Brian said go 2 steps colder on plug too. Brian is it 2 degree's timing retard for every 100 horse of NOS? its been since 98 since i have raced are used any

I pull 4 per 100

[gimmemud]

What jets do you have in fogger, nos and fuel? Which zozzles, annular or 90*

The AR3933 plug should be fine, I run that plug with 2 foggers and they are just right, have tried 3932's and they were too cold.

[jwhitehead]

Thanks all,

the nitrous/fuel jets are 28/28 , the fuel pump is a BG 400 mounted at the front of the car plumbed with #12 an braided lines to a fuel log, #12 feed the carb and #10 feed the fuel solenoids.

[ARUSSELL]

I was hurting plugs then went to a .018 gap and colder, running great.

[bjuice]

i use to run a holley blue pump just for my NOS. when we set the pressure we set it on 3 or 5 pounds free flowing on a 250 shot. like Brian said go 2 steps colder on plug too. Brian is it 2 degree's timing retard for every 100 horse of NOS? its been since 98 since i have raced are used any

hammer is dead on what Nos recommends..2 degrees per 50hp...
i was overkill when i ran my Nos..i free flowed at 6 psi, with a HOBB switch.

[jwhitehead]

I have a billet MSD dist. with MSD 7AL ignition.

[bjuice]

the bg 400 pump is plenty..what is the fuel pressure dead headed at the motor?

how do you have the Nos plumbed..i understand you have a fuel log..but what is run off the log ? you got a 4 port regulator ??
you got a pic ?..


i think your gonna find your problem in One or both of these area's

1- timing retard
2- plugs either too hot and GAP wayyy too wide

[jmarksdragster]

Carb sounds like an 8896, I would pull the power valves out and jet up to 93 to start along with the other suggestions. There are a few more things it needs, but I would start with that. Try making the motor run NA correctly before you add NOS or you will be chasing your tail.

[hammertime]

I agree with Brian you'll find it most likely in the timing retard is not working properly. I test all mine before I plan to use it.

[farrigno]

have a 502 with a fogger, timing set @ 36, retard set @ 12, 1050 dominator with 88 front and rear jets,everything new, set up 300 shot, bottle full with 900 p.s.i. engine back fires thru headers , shut engine down. Checked plugs, electrode in porcelin on some plugs had started to melt.

set up 250 shot increased bottle pressure to 1100 p.s.i. car ran 1.16 / 60 foot, 5.38 @ 127 mph.

SB2 406 small block ran this good, what am I missing?????first the botle pressure @900-psi is too low and will only get lower at the end of the run,as you use more nos.i would get it @ 1000-psi and purge it down to 950,at start of run so it should end @ 900psi with a 250-tune.1100-psi is too high.also a 250 shot at 28/28jetting is fat.you should look into the motor to see if you didn't damage it when you melted those plugs before you go any further because if you have some piston damage you will put oil into th motor and then bang.just my 02

[gimmemud]

Thanks all,

the nitrous/fuel jets are 28/28 , the fuel pump is a BG 400 mounted at the front of the car plumbed with #12 an braided lines to a fuel log, #12 feed the carb and #10 feed the fuel solenoids.


You will see more power and way better response if you will go to a 28 fuel/ 32 nos jet spread and use 6 lbs of fuel pressure to start with, you may have to go up or down 1/2 lb to get it perfect but it will be a good start. Alco as Farigno mentioned get your bottle pressure up to 1000 psi and purge it down to 950 psi before the run. Those fuel lines are overkill, a 8an to the carb and 6an to the soleniods is plenty.

[jwhitehead]

wow, i never expected so many responses, Thanks for your help. Everything made sense to me with the exception about pulling out the power valves, why and should the holes be plugged or left open?

Also the fuel log is a BG, it has a built in reg. with multiple feed lines, I use one with a tee to feed the carb and the other has a tee and has a reg feeding the fuel solenoids. And of course the nitrous is fed from the bottle to the nitrous solenoids.
I can adjust the pressure at the log regulators or at the fuel pump. I can turn the pump on and the pressure is @ 10 psi , it doesnt deadhead because it has a return, I did block the return and the guages pegged out.

Now, based on your info, sounds like:
pull power valves and increase jet size
bottle pressure too low
timing retard not working
plugs too hot
plug gap too large
maybe change nitrous jets to 28/32??????? help

Did I miss anything?

[bjuice]

if i read your post right your fuel log is regulating the out ports of your fuel log and then you have another regulator to your Nos fuel...

if this is the case..this is BIG,BIG No-No...you do not supopose to regulate a line that is already regulated....this spells disaster.

You need your Nos fuel side fed straight from the fuel pump regualted one time..or take off the fuel log and run a regualtor that has a free flowing port...run the fuel lines to your motor and regulate off main regualtor..run the Nos fuel supply from FREE FLOW port to its own regualtor and test flow the Nos fuel from that Independent regulator. Holley silver regualtors are a popular choice of regualtors for dedicated Nos fuel feeds

bottom line regulate your Nos fuel 1 time

i hope that made sense ... :roll: ..lol

[gimmemud]

wow, i never expected so many responses, Thanks for your help. Everything made sense to me with the exception about pulling out the power valves, why and should the holes be plugged or left open?

Also the fuel log is a BG, it has a built in reg. with multiple feed lines, I use one with a tee to feed the carb and the other has a tee and has a reg feeding the fuel solenoids. And of course the nitrous is fed from the bottle to the nitrous solenoids.
I can adjust the pressure at the log regulators or at the fuel pump. I can turn the pump on and the pressure is @ 10 psi , it doesnt deadhead because it has a return, I did block the return and the guages pegged out.

Now, based on your info, sounds like:


pull power valves and increase jet size
Yes use power valve plugs, jet up 4 sizes to start.

bottle pressure too low
Yes get pressure up to 1000psi and purge down to 950 psi

timing retard not working
Check it

plugs too hot
Not neccesarily, AR3933 should be fine

plug gap too large
26-35 should be fine

maybe change nitrous jets to 28/32??????? help
Deffinatley, and flow the fuel to 6lbs of flowing fuel pressure. If you dont have a flow tool, buy one or build one, never trust an inline gauge.


Did I miss anything?
Be sure to bring extra underwear :lol:

[jwhitehead]

Thanks, everybody, looks like we got enough information to make this thing run. Will let you know how it does.

[cepx111]

Man I'm glad I dont run Nitrous, what a headache!

[russ67chevelle]

CEPX111... I CANT EXPRESS HOW A MID 8 SECOND PASS FEELS LIKE LAUNCHING WITH A 275 SHOT OFF TRANSBRAKE RIGHT OUT OF HOLE :shock: !!!

CAN I GET AN AMEN??? :D


OH BY THE WAY MY HANDS WERE TWITCHING FOR A GOOD HALF AN HOUR AFTER PASS...

[Tod74]

CEPX111... I CANT EXPRESS HOW A MID 8 SECOND PASS FEELS LIKE LAUNCHING WITH A 275 SHOT OFF TRANSBRAKE RIGHT OUT OF HOLE :shock: !!!



probably feels like warm mush in the underwear...bet it smells too.

[hammertime]

Man I'm glad I dont run Nitrous, what a headache!


Its simple, but like everything takes a little bit of know-how and a lot of reading up on the nitrous system you'd like to use.

3 years ago I knew nothing about nitrous when I purchased my first kit.

[demented]

Man I'm glad I dont run Nitrous, what a headache!

Once you get the jist of nitrous,you won't run without it. I love it. I like running nitrous better than running blower motors.

[bjuice]

NOS will make one run NO DOUBT !

I think the orginal poster got some good info.

i am still left concerned about HIS DOUBLE regulation of the Nos Fuel line..

other than that he will be set.

Two things you CANNOT screw up in ANY NOS set up is Timing and Fuel..both end at the same disasterous road.

Timing- "When in Doubt take it out"
Fuel- "Better FAT than Foolish"

[chevyfireball]

have a 502 with a fogger, timing set @ 36, retard set @ 12, 1050 dominator with 88 front and rear jets,everything new, set up 300 shot, bottle full with 900 p.s.i. engine back fires thru headers , shut engine down. Checked plugs, electrode in porcelin on some plugs had started to melt.

set up 250 shot increased bottle pressure to 1100 p.s.i. car ran 1.16 / 60 foot, 5.38 @ 127 mph.

SB2 406 small block ran this good, what am I missing?????

Those carb jets are lean. Depending on altertude etc I'd be running 90-92's. 1100 psi is too much. The nitrous will be turning nearly 100% to gas. Should be 900-1000 psi. You should be running cold plugs with that much nitrous - 9's or 10's

[chevyfireball]

CEPX111... I CANT EXPRESS HOW A MID 8 SECOND PASS FEELS LIKE LAUNCHING WITH A 275 SHOT OFF TRANSBRAKE RIGHT OUT OF HOLE :shock: !!!

CAN I GET AN AMEN??? :D


OH BY THE WAY MY HANDS WERE TWITCHING FOR A GOOD HALF AN HOUR AFTER PASS...

Know the feeling. I'm running a 634ci with 650hp nitrous on two stages. Done a 7.06 at 192mph. Just bought a Neal Chance aluminum convertor. Should break into the 6's now. YeeHaa!

[undertaker598]

AMEN, AMEN, AMEN. I RUN A 300 SHOT RIGHT OFF THE TRANSBRAKE AND ANOTHER 300 ON A TIMER .040 OUT. AND AFTER MY RUN I USUALLY PUKE MY GUTS OUT. OH! IT IS SO MUCH FUN!!!

[russ67chevelle]

i started laughing while reading the puking my guts out!!!thats funny.but id bet you probably were,i was shaky for about half hour.my converter is not right,someday maybe next motor rebuild i wanna see if i could reach the high sevens.take care

[twobad1]

itll make me crap?&puke my my guts up?
I'll have to try it!!!