Nitrous jet sizes

[TURBOTWISTER]

Hi,
we are experimenting with nitrous for the first time.mostly out of curiosity.what i need is some opinions on jet sizing.i realize that companys like NOS and NX have some base sizes to go by but as any experienced nitrous tuner will know,these numbers are very conservative.i would like to here from some of you that either use nitrous or have used it to give me your jet combos and the results.

many thanks,Nick

[JayC]

Id be more concerned with boost control and whatever you use for a chip. The NOS jet sizing is somewhat conservative but not terribly. If you dont have a good handle on your boost control and timing then I'd work those out first before getting too happy with jet sizing.

[TURBOTWISTER]

I totally agree jay.this is on a mid 10 second car on c-16.it uses an electronic boost controler so the boost will be the same on or off the nitrous.
i had timing taken out of the computer.it will be now at 22 degrees.down 4 degrees from 26.

[Razor]

Boost control is the main issue, when you hit the button.. it will spike big time.

Then you need to look into the reduced timing.. 22 may still be too much.

The fuel jetting NX and NOS gives should be close enough, if anything I would drop more fuel to prevent leaning out. A WB should be used to monitor.

All the above while it can be done with a chip... will get complicated.. An aftermarket computer will start making sense(FAST, BS3, AEM, etc)

Keep us posted on your progress. I'll be running nitrous pretty soon here and use methanol for the fuel.. :racer: I'll post as info becomes available.

[buicks4speed]

NOS kits are fairly rich. On a typical plate system, I pull out several jet sizes and fuel pressure to lean it out from being so rich. I generally "square" my plate system jetting on the low fuel pressure setups and adjust the fuel from there. It is designed to be safe so people first using it don't burn things up with insufficient fuel systems. You can always take fuel away but it is ususally too late once you figure out you needed more. NX jetting seems to be a little closer on there jetting and only use/need pressure adjustments to dial them in do "dead-on". Adjust the timing to the heat shown on the electrode strap and the fuel to the pocelein. Dial down the boost on intial passes to keep from overboosting, then add boost or adjust as necessary. I know v-6 guys read there o2 volts and knock but I would watch your plugs to as o2 are not 100% all the time with race gas.

On your boosted application, as you well know, you need a boost reference regulator if you are using a dedicated fuel system for just the nitrous. I also say that it is a must to run a fuel-safety switch in case of pressure fall off to shut off the nitrous. Whether running dedicated system or off factory.

On small nitrous shots under 100-125, you will rarely need to do much more than just pressure adjustments to get it perfect.

[buicks4speed]

Just know that you can kill any benfits/HP from nitrous from getting "Too-Safe" by adding too much fuel. I would not add any more fuel than suggested by manfacturer with jet or pressure.