do i need a strong bottom end or top end for large nitrous??

which one is more important?? beef up my bottom end or my top end?? i'm planning to use forged summit rebuild kit plus forged crankshaft to beef up my bottom end, and LT4 hot cam kit with stage 2 LT1 ported and polished heads for my top end.......which one needs to be stronger?? top end or bottom end....thanks guys

BTW, i'm gonna run mostly 150 nx wet shot, but sometimes i might run 200 shots with race gas, just to win a race;)

thanks for your input:cool:

The bottom end see's all of the power and if it fragments itself you have a big problem on your hands:( It could possibly take out a nice top end package also!:eek:

Go with something more than a Hotcam too please:D

Get a bigger cam, then talk about large doses of nitrous. A lot of stock cams have as much duration @.050 as the LT4 cam does.

DEFINATELY bottom end. as said above that is what takes all the abuse.

do you think summit bottom end rebuild kit is enough?? or should i go with something stronger and more expensive....my budget is only $3500 for everything:(

also what cams do you guys suggest??

if you are looking for only occasional 200 hp hits,that kit will be fine.

Originally posted by RacinLT1
if you are looking for only occasional 200 hp hits,that kit will be fine.

so that kit will be able to handle about 1 bottle a week of 150 - 175 shots of nitrous?? i really wanna make this engine last for a long time though.....i will also upgrade my fuel pump along with my ignition. i'm gonna be putting 255 walbro intank fuel pump, with MSD 6al, with 8.5 msd wires and coil....what do you think??? thanks

my stock parts have lasted a long time with a 150 to 175 shot.

a forged bottom end like that will be fine.

remember,it isnt nitrous that breaks parts,it's a bad tuneup that will break parts.

Originally posted by RacinLT1
my stock parts have lasted a long time with a 150 to 175 shot.

a forged bottom end like that will be fine.

remember,it isnt nitrous that breaks parts,it's a bad tuneup that will break parts.

WOW, that's new to me.....so a good tune up is the key to a long last engine?? sorry to bother again, but do you know where i can get a good tune up?? :)

thanks so much:bow:

Originally posted by TMDZ28
WOW, that's new to me.....so a good tune up is the key to a long last engine?? sorry to bother again, but do you know where i can get a good tune up?? :)

thanks so much:bow:

I think you guys are on two different pages.

He is trying to tell you that it is more often the nitrous tuner's fault for engine failure. Granted nitrous adds a significant amount of cylinder pressure and stress on the bottom end, but he is saying that a properly tuned nitrous system is just as important if not more important than the parts you put below it. Even the best bottom end in the world wont last without fuel :).

a good tune up comes from experiance and knowing your limits.
i have been using nitrous on various cars since 94,and it is something you learn.

i wish there was a good place to get a good "tune up" but every car is different as is locations/weather etc. patience leads to good tuneups,as well as knowing how your car reacts to nitrous and how it runs in general.
dont get greedy,that leads to a bad tuneup.

im sure if you went to some of the BIG name nitrous shops like Applied Nitrous Technology,John Phillips from NX,Steve (?) from NOS they can get you on the way to a good tuneup,although at a VERY steep cost wich isnt needed with the smaller style shots we run.

thanks for all the info. i'm learning as we speak.....

is there any tuner sorfware that i can use in order to tune my car?? or tuning in this case is using different jets?? i'm thinking about sending my PCM to PCM for less for a good computer tuning. as far as jet tuning, i will stay with what NX gives me, or maybe a little richer. i would rather go a tad slower, and go a tad faster with a blown engine..... :)

again, thanks for all the info guys :thumb:

i am referring to the nitrous tuneup using jets plugs etc.
do NOT go any richer then what they recommend,they run extremely rich as is. my car went flat using NX's recommended jets,but others work fine.

a good computer tune cant hurt,but get the computer programmed for the best NA performance.

as far as software,you can use LT1 edit,but it isnt the easiest thing to figure out. PCM for less or Madwolf would be good choices.

Originally posted by RacinLT1
i am referring to the nitrous tuneup using jets plugs etc.
do NOT go any richer then what they recommend,they run extremely rich as is. my car went flat using NX's recommended jets,but others work fine.

a good computer tune cant hurt,but get the computer programmed for the best NA performance.

as far as software,you can use LT1 edit,but it isnt the easiest thing to figure out. PCM for less or Madwolf would be good choices.

so as far as tuning the jets my self, any advice on how to do this safely?? a friend of mine that installed my kit said that he will tune it for free, but i wonder, why do i need some tuning when NX already provided us with their recommendation.....please elaborate more.....thanks:bow:

all nitrous kits sold for the "basic user" are tuned very rich for safety.Manufacturers always go rich to protect the beginner/newbie,better to be fat and slow then to have every average joe breaking parts and giving nitrous a bad rep, if you are happy with what they tell you to use,dont change.
My car and a few friends cars were too rich with the stock jets,and picked up considerably when we started tuning the fuel jets.Reading plugs is KEY here,as they will show the first signs of detonation by appearing "peppered" (you will see small black dots on the porcelin).

currently i run 2 jets leaner on the fuel side on just about every shot i have tried,but that is MY car,others may vary.
If i ran the stock jetting for a 150 shot,it would surge,and almost foul the plugs.

Originally posted by RacinLT1
all nitrous kits sold for the "basic user" are tuned very rich for safety.Manufacturers always go rich to protect the beginner/newbie,better to be fat and slow then to have every average joe breaking parts and giving nitrous a bad rep, if you are happy with what they tell you to use,dont change.
My car and a few friends cars were too rich with the stock jets,and picked up considerably when we started tuning the fuel jets.Reading plugs is KEY here,as they will show the first signs of detonation by appearing "peppered" (you will see small black dots on the porcelin).

currently i run 2 jets leaner on the fuel side on just about every shot i have tried,but that is MY car,others may vary.
If i ran the stock jetting for a 150 shot,it would surge,and almost foul the plugs.

thanks for the great advice man.....right now, i will run no more than 100 shot with walbro 255 fuel pump, since i have a stock bottom end, after a rebuild, than i'll run 150 - 175 shot.....hopefully i have MSD 6al by then......:thumb:

Hey Dirk I have been running N2o for quite some time and always pull some fuel for my NX kit and was wondering how much you are pulling on your 175hit which I haven't tried yet but was thinking about 73N 39F but don't know if they make a 39? Haven't checked into it yet. I do have a the 73N 41 jets in the nozzle but haven't cranked the car yet form the cam swap. I bought anthoer shark nozzle and solenoids so I am going to dual stage it later I was thinking a 150 on the first stage and a 75-100shot on the other. What you think? I have aforged bottom end and will pulll about 6-8 degrees. Later Clint

I've also found my car seems to like 2 steps lower fuel than NX' chart.

One thing I discovered was that this works out to:

Divide the fuel jet by the n2o jet.
Shoot for around 0.56.

That seems to be the ratio that works well for the normal shots (150 and less).

Of course, this may be different for your car. :D

Originally posted by JSK333
Divide the fuel jet by the n2o jet.
Shoot for around 0.56.




:confused: :confused: :confused:

can you give examples.....i'm an idiot:( please

thanks :D

im running a 35 fuel jet for my 175 shot. if i remember right they called for a 37.my car is at my buddies shop getting some suspesnion work done,so i cant check my jet chart.

i pull 5 degree's of timing and the car is still a lil on the fat side.I always run 104 unleaded on the bottle,and always check the plugs which are ngk tr6's.

Also,if you have the forged bottom end go for the dual stage,but i would do the smaller shot first,then come in with the big 2nd stage to help with traction. Just make sure your fuel system is up to it,and the plugs look good.

Originally posted by TMDZ28
:confused: :confused: :confused:

can you give examples.....i'm an idiot:( please

thanks :D

Sure. :)

The NX chart says 52/33 for the 100-shot for LT1s. 33 / 52 = .63. I use 29 or 31. 29 / 52 = .557, and 31 / 52 = .596.

For 150, they say 62/38. That's .61. I use 35, I believe, which would be .56.

What I'm saying is the ratio stays about the same, whether for NX or mine. NX is always higher, low .60s, meaning more fuel.

It's just a quick way to see how if you have too much/little fuel for the n2o.

Originally posted by JSK333
Sure. :)

The NX chart says 52/33 for the 100-shot for LT1s. 33 / 52 = .63. I use 29 or 31. 29 / 52 = .557, and 31 / 52 = .596.

For 150, they say 62/38. That's .61. I use 35, I believe, which would be .56.

What I'm saying is the ratio stays about the same, whether for NX or mine. NX is always higher, low .60s, meaning more fuel.

It's just a quick way to see how if you have too much/little fuel for the n2o.

you are using a pretty low fuel jet there.....do you have anything inside your engine?? i'm sticking with NX jet ratio for now, since i have 126K on mine, and have no money to rebuild :cool:

heh,i use a 35 fuel jet for a 175 shot and a 33 for the 150. but thats just my combo,and it works great for me.

like i said,they go way rich for the beginner,lean t out some and you will go faster,but only drop the fuel jet 1 size at a time,or else you can make a big mess.