NITROUS OXIDE ( nos / n2o ) advice forum

Hello all .... my main issues revolve around the limited weight of nitrous I can carry 2x 5lb bottles and the amount of time I need to be spraying for( ideally 60 seconds.) There is ample data and information around for drag racers who spray for only a short time but nothing that I can find for extended time on the bottle, Some information on LSR racing course consists of 2 miles to accelerate then 3 timed miles over which your average speed is calculated. you are permitted to achieve your highest average speed at any of the timed miles.due to this fact I need to be at near maximum revs (11K) naturally aspirated before I hit the timed section.
My questions 1. when is the optimum time to start spraying ,as early as possible and trying to reach my target speed at mile 4 or spraying as late as possible and trying to achieve my target speed at mile 6? your thoughts
2. At what point does the contents and pressure in the bottles begin to drop off substantially as a percentage of the total contents causing a corresponding drop in power?
For your information 2x 5lb bottles ( limited to actual space motorcycle) jet sizes for 140 hp total 4x 35 hp,bottle temps around 35deg C, nitrous ramped up over 10 seconds starting @ 30% to 100% in an effort to maintain traction ( salt lake surface coefficient of friction aprox 0.5), wet system added fuel methanol. my calculations for usage are 100 hp = 1.2 lbs every 10 seconds is this correct?
cheers.

Hi Trev yes a long time lol I should be retired ...BUT. .....granted the post is a little confused ,I'm normally doing turbo with exotic fuels but this year ordered parts will be late so on the spur of the moment I decided to go back to an old record of mine that was taken by others ( a nitrous record) , due to time and money restraints I'm throwing together existing old parts and my road bike ( hayabusa) which is stock, you could say making a purse out of a sows ear.

Condensed version limited to 2x 5 lb NX ( nitrous express) bottles total 10 lb of nitrous, need to spray for minimum of 60 seconds ( do not have a nitrogen pressurizing system) spraying a total of 140 HP using 4x 0.031 thou jets nitrous side again NX jets...... asking the question when is the best time to spray A. early say 5/6 K rpm to benefit from the extra torque and acceleration but use the nitrous early in the run and risk running out before the timed mile or 2. spraying late say near max RPM and reaching the timed mile but not knowing if the benefits are there spraying at near max revs or will it want to over rev and trip the rev limiter? nitrous will be brought in over time.

2. At what point does the contents and pressure in the bottles begin to drop off substantially as a percentage of the total contents causing a corresponding drop in power?
That depends on a number of factors;
1) The amount of nitrous you are flowing (jet size), 2) The position of the bottles, 3) The spec of the bottles, 4) The type and colour of coating or lack of one (which I'm sure will surprise you), 5) the ambient temperature
There are a number of ways you can get better results, than using a 'basic' system, even a WON 'basic' system.

Jet size is 0.031 X 4 nitrous ....bottle position low at rear of swing arm both sides ( only possible place to locate them ), bottles angled at aprox 30 deg from the horizontal , valves at high point.... bottle type NX brand standard motorcycle valve....colour of bottles is white ( no I did not know colour counted) ambient temp ( hot ) averages around 100 deg F some times up to 120 deg F

my calculations for usage are 100 hp = 1.2 lbs every 10 seconds is this correct?
That sounds rather high to me but as I haven't had to provide the correct figure for many years, it's slipped my mind for now, so I'll have to check my records to give you the correct figure but again whatever the figure is, you can't change it so it's of no real consequence to what you are trying to achieve.
The key things to aim for are; Consistent pressure and Maximum efficiency.
If you can either send me pictures of all parts of your system fitted to the bike, to enquiries@noswizard.com or better still, post them here and I'd be happy to assess them and give you as much advice, on how to achieve your goals as possible.

these calulatios for usage are from my old notes back in the day thats why I was asking if they are a valid calculation......no pics yet as I'm still building

Thanks for the reply:) If I ever find the time I would love to do a full blown revo set up with 20 lbs of n2o and a nitrogen pressure set up and shoot for the moon

Thanks Trev for the honest answers:) .... I'm well aware of the shortfalls and if time and finances permit I would like to do a proper revo system one day.
cheers
Gary.

If you decide to continue with what you have, I'd remove the valves and remove the dip tubes.
I'd then reverse the mounting of the bottles, so the valves are at the lowest point. As the angle is quite shallow, you'll probably need to fit very short dip tubes, that are bent in such a way as to have the open end as close to the lowest point of the bottle as possible. Alternatively I'd mount the bottles vertically (or as near to vertical as possible) and not bother with fitting any dip tubes.
Next thing to do is remove the white nylon coatings and either leave them bare metal or PAINT them with a thin coat of BLACK PAINT.
If you can't reposition the bottles, try to locate some nylon tube (the type used in pneumatics), that will side inside the braided hose, to reduce the volume. If you can reposition the bottles, you won't need the pipe mod.
Finally, I suggest you do whatever mods you can, to use nylon pipe instead of braided hose from the solenoids forward.
These mods will ensure you get the best results from what you have.

Hawkwind - good to see you getting active again! I’ve like the original thought I’ve seen on another site I think - can’t remember where at this time.

I too wish I could go to a revo setup. Ransom Holbrook has been very helpful with sharing information - I have benefitted a lot from his suggestions and what I have learned here too.

Since you are already running two separate 5 pound bottles — maybe consider running them as two separate systems? Use one bottle to get up to speed, and then as pressure starts to drop, switch to the second system to sustain the speed?



Last year I swapped from a cobbled up system that included a WON pulsoid to a full WON system from bottle valve to discharge tubes. I say a definite increase in speeds for a given level of nitrous. A 25 shot this past year put us faster than a 50 shot had been the year prior with no other changes to the aero of the bike (and a slightly smaller engine!).

A lot of people that use nitrous in drag racing don’t care about efficiency - just throw in bigger jets. But landspeed racing on a motorcycle, efficiency becomes much more important! I was impressed with the improvement of the full WON setup.

Good luck! Let us know how you get on!