I read once someone said a nitrogen push system wasn't NHRA legal, so I wouldn't be able to run it at the drag strip. So, I checked with Houston Raceway Park, the drag strip I go to here in Houston. This is the reply I got (below). Looks like they don't have much of a problem with it.

Is there some "official" place I can verify this?

-Mark




Mark,

If the bottles are properly mounted with the proper venting system in place, I do not know why it would be a problem. If there are some drawings on how this set up would work, I would be happy to look at it. Of course, this isn't an official ruling, but I believe that the NHRA guidelines are directed toward the safety aspect which primarily focuses on the mounting, plumbing and venting of the bottles. If these factors are maintained, I think having a regulated pressure source is a lot safer than heating metal bottles.

I hope this helps.

Thanks

Gerald

 

Sweet....I have never actually seen in writing that they were illegal. Even if they were illegal..for racing days...I have a better design that would be legal. Im saving that one.

anyone want a nitrogen push??? Ill wip one up for you??

 

Hell yeah I'd like one!!! Where do I sign up! PM me por favor!

 

From the NHRA rule book

Nitrous Oxide
The use of any agents other than NOS as part of, or mixed with, this pressurized fuel system is strictly prohibited. All bottles must be securely mounted, stamped with minimum DOT 1800 pound rating, and identified as nitrous oxide. Nitrous oxide bottle(s) located in the driver compartment must be equipped with a relief valve and vented outside the compartment. System must be commercially available, and installed as per manufacture's recommendations. Commercially available thermostatically controlled blanket-type warmer accepted. Any other external heating of bottle(s) prohibited.

That very first sentence means nitrogen push is illegal.

 

i'm not sure on the zero tolerance rules of NHRA but isn't nitrous nitrogen and oxygen??? if thats the case i'd consider it the same thing as nitrous since it's still nitrogen and wouldnt be considerd a "other agent" since it's already a gas in the nitrous bottle. and as far as the mixing goes again it shouldnt matter since nitrous already has nitrogen in it. so i guess to be technical your adding not mixing. which the rules do not state you cant add nitrogen. sniff sniff do i smell loop hole????

 

Are they referring to nitrous as a pressurized fuel system? I don't think that's technically accurate, since it's an oxygen source and not flammable by itself. In any case, I would imagine the gist of that rule is they don't want you mixing gasline & nitrous in a bottle & pressurizing it to 1500 psi

I'll reply to the track guy & quote that rule, see what he says.

 

What exactly is a "Nitrogen Push" Thanks for the lesson!

 

Usually, to increase the pressure in the nitrous bottle, you heat it. With a nitrogen push system, you use a regulated source of nitrogen (from an on-board bottle & regulator or pressure switch) and connect it to the neck of the bottle, through an auxiliary port on the bottle valve. The nitrogen doesn't go through the siphon tube, but goes on top of the nitrous to maintain constant pressure & push the nitrous out when your solenoid opens up. Even with a bottle heater, the pressure in the bottle will drop when you spray, and by the end of the run may be down significantly. With nitrogen push, the nitrogen regulator will open up quickly to keep constant pressure on the nitrous bottle so it's almost always at 1100 psi or whatever you set the regulator at. Plus, you don't have to wait for the heater to warm up.

I don't have one, but sounds like a slick idea to me. You can squeeze the last pound out of the bottle and still have full pressure. When the nitrous runs out, you'll just run rich. Nitrogen won't hurt the engine if it does get in there, although it won't burn. The only bummer is having to let out all the nitrogen (and nitrous) before a refill, but I'm still not sure you have to do that. Seems to me you could just crack the valve on the bottle where the nitrogen attaches & let a little out to get the pressure down. Nitrogen will be on the top, so it'll go out first.

 

LS1M...you probably dont have to let ALL of the nitrogen out...especially if you have a booster pump filling the bottles.

The other trick I ued to use...was to have two bottles. When one of them was nearly empty with 1150 pis of nitrogen in it and maybe 2 lbs of juice...i would remove that one from the car. I would then get the other freshly filled nitrous bottle that was about to be installed. It would usually be full or close to it...but be at like 950 psi. I would then take the old nearly empty bottle with 1150 psi in it...and hook it directly up to the newly serviced bottle with just a direct short hose (shorter the better) and open both valves. This transfers what little juice you have in the old bottle to the new since it comes out first...as well as gets the nitrogen pressure up to near operating pressure. This conserves nitrous AND nitrogen.

 

I really hope the NHRA rulebook isn't referring to nitrous as "NOS". This would be a sad sad day.

 

Ive been thinking about that all day!!!!!!!!!!
On another note-How can you tell how much n20 is left ina bottle besides the obvious of weighing it. Can you tell by the bottle pressure about how much n20 you have in a bottle? I have a electric digital n20 pressure gauge and just wanted to know. Basiclly is there a way to tell how much n20 you have left in a bottle sitting in your car without pickcing the bottle up. Also can you get a n20 level gauge for the bottle?

 

I was thinking you might be able to use a propane gauge to check the nitrous level, or maybe a raytek gun?