This is a follow up thread to the 900 vs 1100psi thread. Are there any other options besides a nitrogen pusher and bottle headers to control pressure? The idea of the nitrogen push system makes soo much sense but being banned by almost all of the major racing assn. makes it a turnoff.

How can you calculate how much nitrous or how many passes you should get out of a bottle?
Phil

 

if your strictly looking to maintain nitrous pressure during a run...you can do a nitrogen push system...but instead of using nitrogen...you can use nitrous. That way youd still be legal.

The only difference is the recovery time of the bottle your using to push with. Youd need two heaters/blankets...all the components of the nitrogen push sytem but just fill it with nitrous. Us the heater in the "pusher bottle" to get pressures in the 1500-1800 range. That will be enough pressure to push the other bottle out ata set pressure (with pressure switch). i would remove the dip tube on the "pusher bottle". that way your just get gas to be used for additional "head pressure" to be sent to the main bottle. Use another heater on the main bottle with pressure switch to reach the initial target pressure. From there...as your making the pass...the "pusher bottle" will supplement the system tomaintain that target pressure in the main tank.

This would be legal...and as effective as a nitrogen push...and really...it would probably last longer thatn a nitrogen bottle...especially if you removed the dip tube. it would just be a question of enough heat and insulation to get your "pusher bottle" up to operating temp before hitting the track.

Nitrogen system is instant because you service the nitrogen to the desired pressure...heat wont ad any pressure to it. But using nitrous this way...somewhat would let you use the "pusher bottle" contents over and over until after so many runs the nitrous vapor being used to "push" cuased the liquid to get too low that it was tough to get it heated back up to pressure.

HMmm...i think this will be my next setup. I LOVED my nitrogen push system and used it for years. i think the nitrous as a pusher without a dip tube would have many benifits.
Would not need to fill the bottle as often
fill the pusher bottle at same locale as the n20 ( no need for gas supply)
legal in all sanctions

only drawback is multiple heaters
wait time to raise pressure in the pusher bottle

 

I was thinking the same thing....
Phil

 

The only thing i forgot about was that raising the pressure of the "push" bottle will be past the point where nitrous will phase shift to neither gas or liquid but more a fog. I would still remove the pick up tube though because I suspect the contents of the "fog" are not linear. meaning more dense near the bottm and less dense near the top.

It would still work fine.

 

Push systems can be a very good set up. The only time I have seen any major problems with them is when guys try and run the nitrous too cold. When nitrous is real cold, say 32 degrees it is very dense and would normally have a low pressure (around 430psi). But when you artificially raise the pressure through a push system you end up with 950psi nitrous with the density of 430psi nitrous which can make it hard to get the fuel mixture dialed in.

Another option would be an accumulator. Our accountant uses one on his dragster it replaces the nitrous bottle all together. It works like any other accumulator does they use compressed air to drive the piston which maintains a constant pressure until it is empty. It has seemed to work well for him he was having severe pressure drop issue, which I guess can happen when you run a Pro-Race fogger with 47 jets squared . The only real issue they ran into was trying to figure out how much nitrous it would need to hold, they ended up about right at the bare minimum for the amount of nitrous he is using. Although this idea is a lot more involved because as far as I know there is no one offering an off the shelf accumulator for nitrous, the one he is using was built by his son as kind of an experiment in feasibility.

 

accumulators are used on most aircraft of decent size. I dont know how that would maintain a constant pressure. Unless it had an external regulator of some type.

accumulators are generally serviced with nitrogen on one side of the floating piston and the other side gets whatver it is that needs pressure to be maintained or exerted on. Hydraulic fluid, nitrous, fuel, whatever. Anyways...in most accumulators of say 3000 psi..the nitrogen side is serviced to 1500 psi. At that point the piston will be all the way on one side at the physical stop. At that point the nitrogen pressure is at 1500 psi. the pressure on the other side is 0 (zero). Once you start introducing any fluid or gas into the chamber it begins to move the piston to the other side...once that piston comes off its stop its now at some point over 1500 psi. The more fluid you push in the chamber..the more the piston moves over...the more the nitrogen is compressed. Once the piston moves over approx halfway of its travel...the nitrogen will be taking up hlaf its previous space so the pressure in the nitrogen side (and thus in the chamber) will also doublt to 3000 psi. But as soon as you begin to release that volume, the piston moves and pressure drops.

so Im not sure how it would be possible to maintain a set pressure using just an accumulator. Unless the accumulator was such a size that the pressure drop was minimal, but that would be huge. Or a regulator was used either on the outflowing end and the total pressure was maintained above the operating pressure...or you could regulate the nitrogen side of the accuumulator....increasingthe volume of nitrogen as the nitrous exited.

Im sure with the fancy stuff out there a near perfect setup could be made that was legal.

 

Maybe accumulator isn't the best description, plus I can be a bit vague at times. The way this one is set up is, you fill the accumulator with the nitrous and then push it out. And there is a regulator on the push side of it. If I rember right they tried nitrogen, CO2 and are now using compressed air.

 

ahhh....that sounds like a good option for an on demand system.

Im gonna have to snag me a 100 ci accumulator from work.

 

So what would the benifit of going this way be better than dual bottles.
I mean this is why I went dual 15lb'ers and dual heaters. Seems that you are going to have two bottles and two heaters anyway, why not just tee them together and run a sho line? I see no bottle pressure drop of any magnitude doing it this way? Maybe I am not hitting a big enough hit? like over 200?
Robert