Phil99vette

iTrader: (11)

I remember someone doing some testing with different bottle pressures and watching the bottle pressure. Do they have the same pressure drop during a pass? We're trying to figure out if we should set the system up @ 900psi or 1100psi.

VENGEANCE

1100. I gained almost 40rwhp from upping my pressure from 900-1150.

Nickn20

depending on the size of the shot yes, bottle pressure will drop during a pass.

PaiN

Zee, I think Phil is talking about setting up the system specifically to run at 900 psi, vs a higher psi which most people run at from day to day.

It was suggested to us to do the same thing Phil. That way you don't have play with warmers etc. But here during the summer you can run into the problem of you bottle already being higher than that, and you would have to purge off a shitload to get it down to 900psi, or try to cool the bottle.

I can't answer if it drops less when you start at 900, vs starting at 1050. Thats a really good question. I've been told its just more consistent when you start from a higher pressure.

I think the best bet would be to have two large bottle, and have them heatsoaked like in a waterbath, vs using a torch or bottle blanket. But I don't know squat so don't listen to me

srsnow

Yes the higher the bottle pressure you start with the faster it will drop. If you are talking about setting up something from scratch you would be better off to use 900psi and adjust the jetting to equal the same total pounds per minute of nitrous as you would using a higher pressure

Edit: just saw the thing about the torch, that is a bad idea the high amount of heat can weaken the bottle and could cause a bottle to fail. Best to use a heater or hot water.

CAT3

iTrader: (9)

I do the 900, jet it where you need it, when you do have to use a bottle warmer it doesnt take as long and time b/w rounds matters.

Phil99vette

iTrader: (11)

I'd like to set up the system @ 900psi and figure out what the fuel needs to be adjusted on hot days to work with high bottle pressure. My car has had problems with going rich @ the end of the run and I think its due to bottle pressure.
Phil

TWS

iTrader: (63)

Yep, bottle pressure definitely drops during a pass. I know that NX calculates jet size on an assumed pressure of 1050 or 1100 (forgot exactly but it is one of those). To run at 900 psi, I'm sure you realize that your fuel jet size will have to be decreased slightly to avoid going rich. I'd call the manufacturer of your kit to see what fuel jet they recomend at that psi level.

tuff

iTrader: (15)

I run my bottle pressure at 1050 and the end of the pass it is around 900.Always seem to be the best tuneup for me.

ShiznityZ28

iTrader: (11)

the only issue i have with 900 is if it drops down to much it can be bellow what the noid needs to open. We have had issues where you get below 850 and some noids don't want to open.

but on the flip side if you jet it for 1100 its got a good chance of ending at 900-950 and being rich at the end of the track.

you could run 2 bottles or only make 1 pass per bottle then top it off again.

PaiN

to bad you can't reference your fuel pressure to your nitrous pressure, kind of like the boost boys do.

srsnow

There should be no problem with solenoids opening below a certain pressure. We have had people tune there systems around bottle pressure as low as 600-700psi with no issues with solenoids.

Mike TexaSS

iTrader: (2)

Racepak does all of that for you. It's a great resource.

The important thing to remember with bottle pressure in consistancy. If you set you tune-up to 900 PSI, then don't run it at 1100 PSI. Also, I wouldn't suggest running the pressure any higher than 1050 PSI. In order to get bottle pressure to 1050 PSI you will get the temperature to a point where nitrous goes through a phase change. Above 1050 PSI some of the nitrous in the bottle will turn into a gas, not a liquid, which is bad for your tune-up and your consistancy. Anywhere from 900 - 1000 is fine. Most big nitrous teams run them between 1000 and 950 PSI. Whatever you decide, keep it the same every time.

-Ben R

Loudmouth LS1

iTrader: (10)

I start my pressure between 1150 - 1200, on a 300 - 350 shot the pressure was pretty low after a full pass and she was gettin pig rich on the top end and losin quite a bit of power, so I put both my 15 lb bottles together, and now I start at 1150 and i'm only down to 1050ish by the time the run is over, big diff! I've never tried starting it at 900, but I just don't see it running better starting that low, I like the higher pressure, it hits harder from my experience!

Mike TexaSS

iTrader: (2)

You were losing a ton of bottle pressure because your starting PSi was too high. If you start at 1000 you'll see less of a drop. Even less at 900 PSI. That is also why your system went pig rich up top. If you drop the launch PSI you'll see those problems go away.

In our Pro-Mod stuff we run 2 10 lb. bottles with about 9.75 lbs. in each bottle. We come close to emptying both bottles after one pass. But our launch PSI is 950. At the end of the run we still have good pressure, even though most of the volume is gone.

Also, a lot of people I know overfill their bottles to try to get a bigger hit out of them. This leads to a huge pressure drop and will hurt performance. You'd be better off to leave a little out of the bottle.

-Ben R

Loudmouth LS1

iTrader: (10)

That's possible, but i've just always done what works for me and I seem to get a better hit off the line with higher pressure. And as it is, even with the pressure as it is, I have to have the 150 fuel jets in with the 200 nitrous jets to even get the system to somewhat lean out and dropped 10 psi out of the enrichment cell, otherwise it was just retardedly pig rich, dropped off the chart under 10:1 air fuel, so I don't know what the hell i'd have to do to lean it out at a lower pressure.

But i'll be changing nitrous setups soon, so maybe things will be diff, i'll try different things, but I still have a feeling she'll run better with a little higher starting pressure.

Phil99vette

iTrader: (11)

My car leaves pretty hard so I'd rather have the A/F right on the big end of the track.
Phil

srsnow

The other thing with running pressures that high is the density goes to hell, so even though you may have a higher pressure the actual density of the nitrous is very low. At 950psi it will be about 5.5lb/gal and at 1050 about 3.5lb/gal to get he same density increase you would have to lower the bottle pressure to 300psi. That could be part of why you are having trouble tunning it.

next

iTrader: (9)

Phil - clear your in box!

ShiznityZ28

iTrader: (11)

We have had issues and i know some n20 companies will warn you noids may not open under low pressure