Wet versus Dry Nitrous Systems

[joea]

its often helpful to bench test your flow rates to know
what the heck is going on..........

using the jet(s) you desire let it flow for x amount of time.......
accurately weigh before and after, now you know your
flow rate (n20 consumption per unit time)........

invest in piston company stock........

[1212FBGS]

flyboy
thats the great thing about land speed racing... you can try your assumptions... if its advise your looking for... start with 2 sets of pistons!!!!
kent

[ddahlgren]

Nitrous has lots of problems not mentioned here for sustained use. First it relies on the fact that the bottle pressure is what regulates flow through the jet. Problem is it is not constant. The second you turn it on it drops and the nitrous in the bottle has to boil off to raise the pressure back up. you have to balance bottle sizes according to how much you plan on using per second so the pressure does not fall. another way is to use a nitrogen bottle and regulator to hold the pressure constant works well but bulky and expensive for a bike. so the example listed of needing 2 pounds to make the run and adding an extra bottle is in the right direction testing the flow with the bottle on a scale might reveal that initially the engine is lean and slowly gets richer as the pressure starts to fall. I would not run nitrous without datalogging bottle pressure.
Dry and wet systems each have their good and bad points. dry simple and if you have a well thought out efi sytem that can add the correct amount of fuel easy to use. They do not or should not rely on the air temp sensor though LOL.. wet systems work well also and most likely to find them in the larger power levels. One gottcha in big power nitrous systems is the nozzle icing under high humdity. The fuel in the same nozzle can help with this to some degree as it is warm.. I have sprayed 300+ hp for 4 3/4 miles in one car it was a tough thing to keep right 10 seconds much easier with twice that amount.. don't forget you can also adjust the 'hit' by the distance between the solenoid and the metering block and nozzles..longer is softer..
Dave

[Stainless1]

Being a nitrous rookie I figure 27 sec./mile at 225 mph. I have been told a 2# will get you 30 to 40 seconds on a four cylinder motor. So if one runs a 2# shots on both sides of one's bike then it is assumed he would have good acceleration mile 4-6. If the wheel starts spinning on mile 4 then one would have a mile to re gain his traction. Do you vets see any problem with this reasoning? Please let me hear you.

You need to work on your clock, miles take about 16 seconds at 225 
If you are burning 3 lbs per minute you are probably making 30-35 HP max.  You will probably want to use 8-10 lbs to get the power you need.  Listen to Joe A about checking flow for N20 and fuel.  Forget the stuff the manufacturers put out and do the math for yourself.  With the money you make after you buy piston stock, buy rod stock... 
Oh yea, good luck, let us know how things turn out, see ya on the salt 

[Seldom Seen Slim]

Flyboy, I don't like your train of thought:  "If the wheel starts spinning on mile 4 then one would have a mile to re gain his traction." -- from sad experience.  I waited 'til I was about at the 3 1/2 to push the button, and the back tire lit up when the full hit hit.  I pedaled it -- but not enough, so the back tire stayed spinning through most of the 4-5.  Yes, I qualified -- but also yes, I heated up the tire from so much spinning that I blistered it and spent my time in impound scrounging a spare tire and re-gearing 'cause the tire I found was a different size.

I've gone to a slower hit and wheelspin light and hope it doesn't happen again.

[joea]

flyboy, hopefully what you can garner from this
is that many folks falsely believe ya just bolt on
a dry shot or whatever and its easy hp........

its not that easy, at least for 2-5 miles..........

it would be nearly impossible for folks here to give you
all the subtle issues that come to bear.......

[1212FBGS]

nos is great for a 5th gear power wheelie on a street bike.. its also great fun for a 10 sec 1/4 mile...
but boy oh boy will it be a learning experience at the 3 mile marker...
kent

[Flyboy]

Joea--

You're right and that's why this website is such a valuable tool for sources of information from guys like you and others. Life is short and it's not like we can go to the salts every other week to try out our theories and assumptions. I don't like to re-invent the wheel and that is why I ask a lot of questions. You vets have gathered valuable information over the years and many of you like to share it. In return I pass on my limited knowledge of LSR to the guys coming up behind me.  

Having say that I acknowledge that pistons and other valuable components may just melt away with steady nitrous use over an extended period of time, ie. +- three miles. Has anyone done any research on at what period of time one can spray stock components and not reach that extreme temperature where something can melt? In an airplane it's about 425 degrees CHT that I start to worry about piston and component damage. Can one spray for 10 seconds on and 5 seconds off as an example? Does 5 seconds allow sufficient cooling? I know this is hypothetical as there are many variables like different nozzle sizes. etc. Does anyone have a personal rule of thumb? Has anyone oversprayed and suffered engine failure? What did you do wrong? Thanks--

[Flyboy]

Disregard--

[Seldom Seen Slim]

Flyboy:

Here's what can happen.  Folks have told me that I shouldn't bother keeping the damaged parts -- I do anyway, just to be able to give graphic examples of what can happen.

I had planned to mosey down the course with the fat mixture (using a dumb ECU that didn't allow me to switch programs while underway) and hit the button when I got to the 3 1/2.  I pushed the button -- and about 8 seconds later three spark plugs had done their "disposable fuse" thing -- but one of them didn't die soon enough, or the hot metal of the decomposing electrodes kept the fire going -- and so there went a piston.

If you're running a dry shot system, remember that the gas is going into the airbox -- and therefore you don't have instantaneous "on" and "off", so your idea of hitting the button for XX seconds, then releasing for YY seconds won't necessarily work -- it takes a finite amount of time for the nitrous to reach full concentration, and also a finite time for it to clear out before you're back to gasoline only.

Or think of it this way:  Nitrous can be your best friend -- or your worst enemy.  It makes the change back and forth very rapidly. . .

[Stan Back]

Fly, Boy!

Just a note that keeping full throttle on for a mile past the 5 will certainly get someone's attention.

Stan Back

[joea]

flyboy........its not often so much about temperatures
as it is cylinder pressures not timed correctly...........

you can motor down the 5 mile course all day long at relatively
modest or relatively heavy nitrous jetting......and proper set up.....

is as much about detonation is it can be about preignition

it can happen at way rich...and cold egts

be careful, there are lots of nitrous experts out there

you need to figure out how to be your own expert...your
on your way by gathering opinions...

MOST people have had the combustion process get out of control(at some point)
with nitrous and lose pistons and other parts...........

[Larry Forstall]

Stan Back: Flyboy runs the BUB meet so he does run 6 miles. Flyboy: Last year you ran a stock motorcycle well within its' design capabilities. That is the beginner's course and I applaud you for racing; most only talk about it. To go fast, really fast is the big leagues and requires dedication, time and  $$$ . The fact that you are inquiring about NO2 in July means you are way behind the curve. At this point a simple dry kit ( Muzzy should have one) with extra capacity would be all you could do for Sept. Maybe 50 extra HP and that would get you over 200. An accomplishment in itself. Serious racers build a dedicated bike for Bonneville. Whether you wish to sacrifice your ZX14 for speed is your decision. NO2 is the hardest method. The turbo has proven the easiest but the records are all a challenge. That leaves the all engine classes. I am sure a ZX14 could set records in the 1350 classes. Yes I know the engine is too big but the crank could be destroked as part of the build. Plenty of time after Sept. to start for next year. If it was easy, everybody would do it. 

[Flyboy]

Larry you are very profound.  I am behind the power curve as I own a number of businesses. But last year I didn't even own a motorcycle license until June when I passed the DMV driving test on my 14 with 50 miles on it. I like to set goals and then go after them. That's what keeps me feeling young. Thanks for putting up with my questions.

[Stainless1]

Stop by and see me on the salt, stop by and see Joe on the salt.  Everyone is trying to tell you it is not as easy as the advertisements make it seem.  The typical N20 run on the strip or street is less than 5 seconds.  The typical salt run is 10 times that.   
On-off will cause you a lot of problems.  The competitive set up for Bonneville would probably preclude using that bike on the street. 
come by and chat, I know all the secrets, most have been revealed to you already, but I have almost as many parts in my dead pile as Joe, More than Slim... People with thousands and thousands of dollars worth of N20 experience have replied...