J-Rod

Most of our nitrous kits are a derivative of the same kits that many of us bolted on carb'd cars 20+ years ago. In many cases VERY little has changed. So, that got me to thinking.

What are the major issues when tuning a nitrous kit. Bottle pressure and fuel pressure. Those two things seem to hurt folks most often. So, I looked at why.

Ideal bottle pressure is ~950 psi or so. Nitrous at 950psi is a liquid which weighs 5.44 lb/gal. a 20 lb bottle (20 lbs of nitrous) means you have aprroximately 3.676 gallons of nitrous. You need some head space on the bottle (so the top 40% of the inside of the tank is empty). Some folks think overfilling and having more pressure makes more power. It may if you run a in a class that limits jet size, but anywhere else it means that the inital pressure drop will be a huge intial drop, then it will stabilize, then it will drop at the end. So, if your first hit is right, the next will be fat, or vice versa (your first hit is super lean (which is why most folks think it makes power) and the rest are the right ratio. So, you stand a good chance of burning a piston.


Ok, so enough background on the bottle. Its pretty well understood that when bottle pressure drops, it drops pretty quickly. So, I asked myself. Well, how many more passes could one get if the required pressure was much less. So, what would happen if you only needed say 300-400 psi of bottle presssure? Could you get a few more passes before you needed a re-fill. Probably so, but the issue becomes percent of deviation. See, a few lbs off at 950psi is much less of a variation than the same ammount of variation at 400 psi. But, I thought it might be a good discussion to look at what could be done when we concern oursleves with volume instead of pressure.

My most key point in this whole thing more revolved around fuel though. Most systems use fuel at 6-7psi which has been regulated down from rail pressure. So, a small change in fuel pressure from 6 to 5 psi is a 16% change. But changing fuel pressure from 58 to 57 psi is a 1.7% change. Again, fuel pressure is one of those things that tends to bite folks.

So, my question becomes what happens if we use a regulator which supplies nitrous at 300-400 psi, and we increase fuel pressure up so that the fuel coming out of the jet is work harder to atomize itself. We aren't limited by 6 psi. So, a change in fuel dlivery pressure isn't making you go lean or fat.

Anyone have any thoughts on this?

BigBlockChev572

iTrader: (7)

I'm not 100% on what you're asking. But at 300-400 PSI of N20 flow, that just woudln't be enough and would equate to a low shot with proper fuel jetting, am I correct?

n2ojunkie

I think I get it. You mean to regulate the n2o down to 300-400 psi all the time and jet acordingly right? so you would have to run a much bigger n2o jet to get the same size shot as at 950. I am I right? I am no expert but would you get the same atomization at that psi? If so I know they make regulators that could handle the pressure (look at oxygen regulators for welding) I would think the only thing that could be a problem would be if it would atomize right.

Sounds like a good way to utilize more of the nitrous that we buy instead of only useing 1/2 to 2/3 before the psi drops to far.

BigBlockChev572

iTrader: (7)

Oxygen regulators read high for tank pressures but don't regulate into the 300-400 psi range for line/gas pressure.

Ben R

There are already teams using Fuel Injection to add fuel instead of a standard low-pressure type system. It's just one of those things that is going to take time. Fuel Injection is not allowed in some of the big N20 classes.

With the advancements in the last couple of years bringing us scientifically designed distribution blocks, nozzles, solenoids, and N20 specifc flow-benches, tuning a N20 system is a whole new ballgame.

Robert56

iTrader: (2)

J-Rod, the biggest problem I see trying/testing this method would be keeping the bottle cold enough when full. An 85* bottle is approx 950psi, so to get into the pressures you suggest (and keep it there), now we need a good cooler instead of a good heater (NX Fire/Ice?). A dry hit will maintain a/f at these pressures, but n2o volume becomes an issue, now compansating with a larger jet, hmmm... I have some more ideas comments, but have to go eat some turkey.
Robert

n2ojunkie

True but my point is if they can make one to go from 3000psi to 25 why not to 300psi? I dont see why it wouldnt be easy. and I am sure someone makes one, I havent searched form one but somewhere someone should make one

Also at that low psi would a standard syloniod be able to flow enough n2o for say a 250hp shot?

Robert56

iTrader: (2)

Do these type reg without effecting volume?
Robert

BigBlockChev572

iTrader: (7)

I'm a bit confused as to what you're asking. Are you asking if the regulators will regulate within a certain PSI range despite volume of gas?

Robert56

iTrader: (2)

Correct.
Robert

383LQ4SS

iTrader: (33)

These typical gas regulators wont work well to regulate flow of volume. If you bottle is at 800 psi and you regulate it down with a standard gas regulator like a C02 or nitrogen....it wont flow near the volume to give any sizable shot.

I use a nitrogen regultor to power my impact gun from time to time for stuck botls. The tank is 1500 psi and I regulate it down to 250-300. When you squeeze the trigger on the impact that bastard comes alive.....for about 2 seconds...then it just dies because the regulator cant keep up with demand.

I am sure there are regulators out there that will fit the bill...but they are gonna cost more than a standard 02 or nitrogen regulator. And those can run from $200-$500 as is.

Try a google search for "flow regulator"