Going nitrous... jetting advice.

[nakomis0]

My quad is 4 yrs old, 3 months after I bought it new, put a decked out 440 kit . Still has the stock rod, crank and clutch.

Well I've always been thinking about it. ... Today I bought my buddies nitrous kit. I wanted to wait till I replaced my rod and crank but a good deal was there and I took it.

It was also good timing, my buddy (rides a 250r) and me, have been having an on going war about beating each other. Its been a back and forth battle for 4 yrs. I have been owning him the last few times out.

He just blew a crank and is now rebuilding, I know its going to be stroked and a 100% fresh motor. So sense I only had him by maybe a quad or 2 before... I think he should definately beat me after this.

I've had some experiance with nitrous. This kit was on my buddys z400 before, but he got way crazy and blew a nice z400 up in 3 months

So I have everything to do this besides jets and a few clamps.

I don't know what jets sizes to go. We have a local guy who does this all the time to snowmobiles so I will probably go talk to him but I was wondering if anyone on here knew about the proper jetting sizes for the fuel and nitrous. All I would like is 10-15hp shot.

Anyone want to share some advice, please do. Except the weak crank/rod advice keep that chill cause I know the crank/rod is already used and abused and probably not going to take much. If it blows it blows, hell its almost 5 yrs old.

Its a wet system, plumbed in the intake boot before the cylinder.

[frosti108]

im pretty sure you dont need to mess with the jetting if this is the kind of kit im thinking about.
its a wet kit, so it definatly spits out nitrous WITH gas out of the rail right? im pretty sure that means you dont have to mess with the jetting...
with dry kits, the nitrous is added before the carb, without extra gas so that your engine runs extremely lean when u spray. now im pretty sure this is because nitrous basically just lets out extra oxygen to combust, so this means there is extra oxygen, without extra fuel, meaning LEAN... but with a wet kit, the extra fuel is sprayed in along with the nitrous, meaning your engine still runs fine even when the nitrous is being sprayed...
you get what im sayin? but im still not sure about jetting sorry...

now keep in mind that i dont fully know what im talking about, lol,
but i start babbling when im tired so there ya go... :)

[nakomis0]

Ya i was actually meaning the jets for the nitrous kit, I wont mess with the quad jetting, just the nitrous and gas thats being added

[frosti108]

there should be somewhere you can look up what jet size is what shot size... like if you know what company it is, look for their website and there should be contact info you can email someone from the company or some bull**** like that...

what i would do is just put in the biggest jets you have to be safe... the bigger the jet the smaller the shot right?

[nakomis0]

nope, bigger the jet bigger the shot.

I'm going to go talk to a local guy later this week, I just wanted to see if I could learn a bit more before I go talk to him, so i might sound less like a noobie.

i'm gonna google search

[frosti108]

oh :eek2: well then surely start with the smallest jets you have LOL

that way i figure you should be safe

[nakomis0]

heh great advice, to bad I dont even have any jets to start with I think I found the info. Depending on how much psi my fuel pump pushes its as follows....

_______________ HP NOS Fuel
10 psi _________ 14.2 .45 .45
______________ 17.5 .50 .50
_______________ 21.2 .55 .55

3 psi ___________ 14.2 .45 .60
_______________ 17.5 .50 .70
_______________ 21.2 .55 .75

[red2004 TRX450R]

In our racecars and accounting to NOS a wet system has now effect on the carburetor. It injects N2O and gas, so no other gas (jetting) is needed.

One bit of advice. Run it a little rich on the fuel jet so that u don’t get a lean condition and melt a piston.

On our cars we changed the head range of the plug, run a ignition box that retards the timing with the nos hit and run race fuel. All so have forged motor.

If it is an NOS brand system call them !!!!!!!!!! they will help you. very good tech support. If it is not sell it and get one.

Any way look at there sight has all kinds of info in it.
http://www.holley.com/nosnitrous/index.html

[wilkin250r]

I had a NOS system, and I think the fuel pump was 5psi. I can't remember, it's been so long since I've played with it.

I've seen other people playing with nitrous, and I have NEVER seen anybody melt a piston. I've seen rings, rods, head gaskets, and detonation problems, but I've never seen a melted piston, and here's my take on it.

This is just my theory, if you choose to follow, it's at your own risk. Nitrous oxide is a liquid. If you are spraying directly into your intake, between the cylinder head and the carb, then you are spraying liquid nitrous directly into your cylinder. That liquid nitrous will hit your piston and cool it down rapidly, like a cryogenic.

Now, the only danger with a lean condition is overheating. The gas burns completely and the piston gets too hot and eventually either seizes or melts. If you have liquid nitrous oxide cooling your piston, I honestly don't believe a lean condition is dangerous.

Like I said, that's just my theory, but the evidence I have seen supports that theory. This would obviously be a different story if the nitrous was injected into your airbox, because it wouldn't be in liquid form by the time it went through the carb and all.

So, just my personal take on it, if you have direct port injection, I don't think a lean condition is all that dangerous.

[red2004 TRX450R]

wilkin250r
you have no idea what u are talking about. “Like I said, that's just my theory” LOL


Im no expert but I know that Nitrous is not liquid when it comes out. The change form a liquit to gas when injected and that is what caused the cooling effect.

The term melting a piston is not to be taken illegally. I meant denotation from being to lean or to much timing. This can happen at any power level.

The other ways NOS can hurt the motor is to big of a hit witch with will blow head gaskets and if you bottom end is not strong enough it can come apart form the extra load.

Just buy a kit form a good manufacture made for your application and they will tell you what is safe. And don’t try levels that are to great for your set up.

:cuss: :cuss:

[red2004 TRX450R]

nakomis0

I was just looking at you sig and you have high compression so race gas is a must for NOS.
And u have a WB CDI box---- I don’t know much about them but if it advances your timing you may want to get rid of it. Be cause with NOS U want to retard the timing not advance it.

Call up the nos manufacture and they will set you UP.

[nakomis0]

Yes I've been talking with one of our mechanics. Tossing ideas around.

I'm removing my sparks degree key, running race gas, and using the stock cdi sounds like a good idea.

I'm still using the 11:1 piston, .. I keep telling myself I'm not going to use it that much.:rolleyes: :)

I did find this sweet setup. I'm gonna order that bottle and do this install....

http://www.boondockers.com/graphics/Img120.jpg