Topic: Nitrous on 50cc engine

[tbpmusic]

The cause is most likely the fact that you're completely insane.....I applaud you sir.

[simon#42]

no i dont think that is the cause , all two strokes are like that . 80% of the cylinder pressure is lost in the first few mm of exhaust opening .
you do need to find a cure , just throwing endless sets of reeds isnt going to work
its igniting in the crankcase because you have  very very oxygenated fuel in there due to the nitrous . any heat source will ignite it even the underside of the piston .
you need to reduce the nitrous untill it doesnt explode !

[frodef2]

Yea, i just came back from the garage,  and the transfers open only when the piston is almost at the bottom. Not like the cast cylinder i have where they open almost at the same time.
You are probably right about the detonation, and i am unable to source drills small enough to make smaller jets. The current nitrous jet is 0,45mm (18 thousands) and the fuel jet is 0,40mm.
the new smaller jets are in the mail, and i think i'm going to attend the race and do one run.

Thanks for the advise.



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[vfourfreak]

You could be right mate, but frankly I can't think straight - I'm just in awe with what you are doing !!! Just wish I was there to help.

You must have very tolerant neighbours and understanding police. That helps 

Keep up the good work.

Kev

[simon#42]

frode one last thing to try , use a larger fuel jet . a richer mixture will be harder to ignite it might calm things down
good luck mate and whatever happens well done for all your effort !

[Lostboy Steve]

The cause is most likely the fact that you're completely insane.....I applaud you sir.

Lol that'll do it.

[Lostboy Steve]

frode one last thing to try , use a larger fuel jet . a richer mixture will be harder to ignite it might calm things down
good luck mate and whatever happens well done for all your effort !

What about some super high octane race fuel as well?

[scottly]

I am using the smallest jet in the kit. And i run lower bottle pressure than recommended by NX (nx says 1050 psi in the manual), and i try to keep it at 950.

The nx jet size is 18 for the n2o and 16 for the fuel.

Is it advisable to let the n2o pressure go even lower? I assume the flow is related to pressure.

The flow of n2o should be proportional to the pressure, and if the extra fuel is added using a "siphon" type nozzle, the flow of fuel should also be proportional? At this point, I would try reducing the pressure to as low as 550 PSI; you can't do any more damage than you already have suffered.

[frodef2]

frode one last thing to try , use a larger fuel jet . a richer mixture will be harder to ignite it might calm things down
good luck mate and whatever happens well done for all your effort !

What about some super high octane race fuel as well?

I am already running VP racing C14 fuel. Should be enough.




Frode

[frodef2]

Update from the last trial run's.

first run: I swapped the reed for a new 0,12mm and changed the angle of the nitrous jet. i now points to the side of the intake pipe, not straight down the pipe as before.

I tested one high rpm pull, and almost immediate stuttering.

second run:
swapped the reed for DUAL 0,12mm reeds. I stacked 2 reeds on top of eachother. i switched the nitrous and fuel jets, so now the 16 jet is nitrous and the 18 is fuel. i aimed the pirana to the back of the reed.

2 small high rpm tests, that seemed promising, so we thought what the hell.. lets do a run with nitrous on from the start.

and wouldn't you know. it worked like a charm. only started to stutter at the very end of the pull.. By the way, the distance between the lightposts are 50 meters. So by the time it starts breaking up, we are passed 100meters.
This time there where no missfires, and still the reeds took a beating, but much less than before and we ran the nitrous longer. I am starting to think that the damage to the reeds are caused by the opening action. That the nitrous is actually Blowing the reeds open with enough force to bend the reeds. I will upload a picture of the reeds with tapatalk in a sec.

[frodef2]

As you can see. The outlining of the reed supports have rubbed the reed. And the curved part of the reed only start outside the support.

The bending is also much less on the bottom reed. Like it was supported by the top reed

I will go to the shop early tomorrow and make a longer and wider reed stop.




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[Terry in Australia]

That last run looks way more promising mate, well done!

[frodef2]

Good news from the race. We did not win. But we did not break any reeds on 2 runs and 1 test and tune.  The racing was straight ladder, and very little downtime between the races so we didnt have time to even switch back the jets.
We ran all races with 16 nitrous and 18 fuel jets.



Here are the reeds after three 100 meter pulls. No damage at all.



Here is a picture of the winner. Used to be a yamaha aerox scooter.




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[simon#42]

well done !     bloody hell the winner took it very seriously didnt he !

[vfourfreak]

well done !     bloody hell the winner took it very seriously didnt he !

Lovely lunacy ! 

Kev

[Gearheadgreg]

Awesome ! just found this thread..sorry for the late reply,,I have been using Nitrous for 20 years I grew up 3 blocks from NOS systems in Cypress Cal back in the late 1970's they were very much the pioneers of NOS , we were using dry systems back then breaking small Chevy's then they added Wet Fuel and success, When i set up my Supercharged GL 1500 with Nitrous i spoke to the Tech at NOS and my App,, we went 2 size Larger on Fuel jet than standard Carb app.. Also stepped up Main Jetting on Carb larger than any Jet offered by Sudco with a reamer,, Your on the right track with switching your jets as you did..you may even try one more step in Fuel jet to prevent detonation keeping cylinder temps down with fuel added ..HAVE FUN !!     

[Yoshimatic]

I love this thread, its the best seeing things like this.......