Nitrous

Just getting the nitrous thread started again, (my former name was dpearce455)here is a new video, with bigger jets in the fogger nozzle. In the first video I posted before pbp went down I was using a .012 nitrous jet, and .018 fuel, then I tried a .016 fuel, these combinations were good for around 2-3 hp? Im guessing, and this new video is with a .016 nitrous jet and a .022 fuel jet, which I think would be somewhere around 7-8 hp. It was a big difference! It would crank the front right off the ground and try and loop out if when I didnt lean all the way forward.
download it now, this will only last a day.
http://www.angelfire.com/droid/nitrous/nitrous3/nitrous_power_005.mpg
I will try and get someone to host it as soon as my home computer works again.

The link doesnt work for me unless I cut and paste it.

i remember that video. nice work. so nitrous works on 2-strokes then? did you install a sneaky pete system? did you hook up the jet to the intake adapter or carb? also how did you deal with the ratio? is this a wet or dry system? i plan to do the same on my bike.

Yes, it works very well on 2 strokes. In fact, it works so well that I think the engine will easily handle the next step up in the jetting (about 11-12hp), but I dont think I will be able to! Going to have to lean far forward! With the jets in it now it practically rips my hand off the button, and I cant really hold it for more than a second unless you lean way forward, because it will keep pulling the front wheel higher the longer you hold it! Its kind of scary but alot of fun. It was a sneaky pete system, but was converted to a wet system. I put the fogger nozzle about an inch outside of the velocity stack, if you put it in your intake tract, the tip of the nozzle will take up about a quarter of the area of your intake path, and will restrict airflow. I always run it rich to be safe.

so basically you installed the nozzle with the velocity stack, then made the carb to run a little richer than normal? seems like it should work really well then.

how did you convert the sneaky pete system to a wet system?

i might install my bottle near the exhaust so it warms up for better usage. i also might install a purge system as well.

I left the carb alone, I meant that I always run rich on the jetting in the fogger nozzle. Basically to convert to a wet system, you need a fuel pump that will provide at least 5 psi, a fuel solenoid, a T fitting for your fuel line, a fogger nozzle, and misc. things like fuel line and fittings. I open the nitrous and fuel solenoids seperatly, so there is always fuel flowing before and after the nitrous solenoid opens, to prevent any possible chance of leanout due to the pressure differences. With N20@approx 1000psi compared to fuel@approx 5psi, one (nitrous) will get there faster than the other and leave later if you hit open both solenoids simotaneously, and you dont want nitrous when you dont have fuel! My bottle is close to the exhaust, but I insulated it, If I were you I would get the bottle as far away as possible, even though theres a safety blowoff I dont think its worth the risk of using your exhaust as a bottle heater. I would also suggest that you lose the rocket key if your going to run nitrous.

why would you not run a rocket key? make the engine misfire?

Make the engine detonate. First of all I have read enough times (on PBP) that rocket keys advance the timing too far and will eventually burn up your engine, and that is without even using nitrous. The general rule for nitrous is that you have to retard your timing more and more as you run more and more nitrous, (about 1* for every 25hp), so your engine wont detonate. (nitrous speeds up the flame front speed, retarding the timing will make the peak cylinder pressure happen more and more after TDC, rather than too soon after TDC, where there is less leverage on the crank) The amount of nitrous you are able to run on these pocketbikes is so small that retarding timing isnt nessecary, but if it is true that the rocket key advances your timing too far, then you are better off playing it safe and not using it, to avoid detonation. I was thinking of eventually putting in a rocket key backwards to retard the timing 5*, overkill I know, but if the engine is still together when I get to 15 hp and greater, it will add a extra margin of safety.
In short, advancing your timing and using nitrous isnt a good Idea, unless you have a timing retard activated only when you are squeezin'.
long answer for a simple question, I probably left something out but hope it makes sense.
-david

****. ive installed nitrous before but that'll be too much work to do a custom one-off wet system for my bike. oh well.

well i am not one to give up and i really like the idea of nitro charging my cateye bike so i am still gunna do it...although newman since you seem to know a ton about running the nitrous on pocket bikes could you send me an email with like step by step on what to get and how to set it up on my bike. thanks man...oh yaa i have a 04 yellow 49cc cateybike. thanks alot man.

I would not give up, I think it is well worth it, wasnt hard to put together, your biggest hurdle will be the cost. Everything I have totals up to around $400, but I had alot of it lying around already. I actually baught my bike just to put nitrous on it. Whats cool about the midbikes is that you could just wire it right in since its 12v. The benefit of a wet system is that you have the option of using a much bigger nitrous jet, and the power isnt affected while not using the nitrous.
I know just as much as you do about nitrous on pocketbikes, which so far is basically that they will handle at least 7hp, and Im willing to bet even more than that, Ill find out soon enough. The same principles of nitrous apply, regaurdless of what kind of engine you put it on, just use common sense. Ill post up a list of main things you need, later when I have time.

im back on the nitrous train. ive decided to do it, since i realized how easy the fuel pump setup with solenoid and lines will be.

a few more questions, when you T-lined your fuel line, did you T the fuel return line or the feed line? also since your fuel solenoid and no2 solenoid are not wired together, that means you have to activate the fuel first before the nitrous? have any pics of the nitrous mounted on the bike? pics of the switch panel? i plan to mount a switch in my throttle so on WOT and the arm switch on, it'll activate.

dtp, i really recommend you have a professional do the install for you if you need a step by step listed. it'll get pretty complicated with all the wiring and lines you have to run.

a few more questions, when you T-lined your fuel line, did you T the fuel return line or the feed line? also since your fuel solenoid and no2 solenoid are not wired together, that means you have to activate the fuel first before the nitrous? have any pics of the nitrous mounted on the bike? pics of the switch panel? i plan to mount a switch in my throttle so on WOT and the arm switch on, it'll activate.

Yes, the T fitting is in the feed line, my carb doenst even have a return line. If you have the room you should use a seperate, dedicated fuel tank, and use high octane gas, just for when the nitrous is activated.
Yes, since the solenoids are wired seperatly you have to activate them seperatly, but that is the point. It would have been a little easier to activate them simotaneously, but with them wired seperatly you can make sure you have fuel flowing before and after the nitrous is flowing, just another margin of safety.
here are some pictures of the fuel pumps, arming switch, activation switches (2 kill switches), battery up in front of the forks, and the mounted fogger nozzle.

nice pics. what i plan to do is use about a foot of fuel line, and about 2.5 feet for the nitrous line, that way the fuel hits first. at the rate that nitrous flows, i may need to use 4 feet though. when i do the install in a few weeks i'll have to do some flow testing to see how many feet of line i'll install.

I thought of doing that, but came to the conclusion that activating the solenoids seperatly is the safest way. The reason for this is, if you have your fuel line shorter than your nitrous line, yes your fuel may get there first, but... there is another problem. After you let off the activation switch, closing both solenoids, your fuel, at around 5 psi will stop flowing instantly, but your nitrous, at around 1000 psi will still be flowing, so even after you close the solenoid it still comes out for about another second, the longer the nitrous line the longer it will last after you shut it off. (Since the nitrous jet restricts the flow, there is still pressure in between the solenoid and the jet after the solenoid is closed.)
When I close the nitrous line, but am still holding the fuel solenoid open, it still pulls for another second as if the nitrous was flowing. Hook up a fogger nozzle to your bottle, open the nitrous solenoid and you'll see, it doesnt stop right away after it is closed.

hm good point.

what'd be interesting to try is fill a bottle with 50% nitrous and 50% fuel mixed together. if that worked that would work pretty well.

Im not sure, but I dont think that would work because first, nitrous is liquid in the bottle but comes out as a gas, while your fuel would still be liquid when it comes out. I think the fuel would get too cold, also. If you mixed it 50/50 im pretty sure that one would run out before the other. Also, I think that a bottle mixed with nitrous and fuel could be an explosion waiting to happen. I'd just go with what has been proven to work, unless you just want to experiment with nitrous, in that case pocketbikes are perfect because you dont risk blowing up your car engine... $100 for a new PB engine vs. $$$$$ for a new engine for your car.
If you want to experiment, go with propane for the nitrous fuel enrichment. It has an octane rating of like 110 or something, comes out cold and vaporized, is cheap and readily available, and already under high pressure. (no need for a fuel pump, and you probably wouldnt have to worry about the seperate activation switches) come to think about it, I might have to try that next...
-david

yaa i actually know alot about nitrous i wanted that to compare how he set it up to my nidea of how i was gunna set it up. lol professional i am pro...lol. but yaa im deffinitely doin tghis as soon as i work up the cash. quick question do you need any brand o hp pipe ond air filter w/ vstack to rig this? j/wondering. but yaa i am no doubt doin this im glad you are too boogie.

i think youll be doing it before me tho. dont plan to put the nitrous on for a few months.

since you are going to have to rig it up anyway, it doesnt matter which kind you get, except I think it will be easier with the air filter like mine, rather than a cone shaped one. I couldnt see any easy way to do it with the stock air filter. My engine is all stock, except for the v-stack and air cleaner, no pipe or anything... not yet at least..