This is what happens when u fit NOS to a pocket bike

[mech_eng_matty]

Mmmmmmm, i did think that myself while i was writing the post. It is true, the constant heat generated would be enough to negate the more viscous oil i would assume, but without actually doing some calcs on it or even better, testing it, i can't say either way.

It is an interesting concept though, i would just think that it'd take a bit of a redesign of the motor to accept the charge of NO2 and have it make a substantial power benifit.

The cooling effect of the NO2 could also perhaps be created by putting a dry ice (liquid nitrogen) cooler on the intake side after the reed valve, this would attempt to cool the inlet material enough to create a larger temperature differential between the intake fluid and the combustion chamber creating more power. However it may just end up hydraulic-ing the fuel/air mix to a point where it just floods the engine (bit like starting on a cold day).

Why can't all the topics of conversation be like this??!! It is a good thread, with a decent conversation relating to a seirous matter. I think this is what miniriders is missing at the minute and is why guys like Flarry are cracking the ***** a bit.

Thanks to all you guys who are posting decent responses, its nice to have an intelectual conversation on here for a change!

 

[pegleg]

Mmmmmmm, i did think that myself while i was writing the post. It is true, the constant heat generated would be enough to negate the more viscous oil i would assume, but without actually doing some calcs on it or even better, testing it, i can't say either way.

!

I will ask my wife when she gets home in regards to this, she works as a industrial chemist for one of the largest lubricant manufactures in the country.
She will have all the calcs and specs on every oil available today.
A lot of her day is spent on analyzing used oils, looking for ways to improve them.

 

[Ruby]

It would be ideal just to plumb the nitrous injection into a tapped hole in the head (similar to and near the spark plug). However, the problem now is setting the system up to inject the nitrous at a timing consistent with good combustion.

It would, in my view, be more beneficial to power to inject it through the head on about 1/3 of the up-stroke (compression). Any earlier and it some would be lost through the exhaust camber. Also this amount of leaking nitrous into the expansion chamber may affect the role of the expansion chamber as the exhaust gases are now too cool for the extraction process. Any later on upstroke and there would be little time to 'squirt' the required amount, especially at higher rpms. There should be no injection on the down stroke for the obvious reasons of cooling the exhaust gas charge and affecting the extraction process, and also the waste of unused nitrous out the exhaust system. The exact timing of direct injection of nitrous would need to be tested and tuned, but through the head, and not through the camber, seems the better method to me.

Removing the injection of nitrous in the chamber altogether seems the ideal solution. Then there would be no need to fret about air/fuel/oil mix etc.

 

[mech_eng_matty]

It would be ideal just to plumb the nitrous injection into a tapped hole in the head (similar to and near the spark plug). However, the problem now is setting the system up to inject the nitrous at a timing consistent with good combustion.

It would, in my view, be more beneficial to power to inject it through the head on about 1/3 of the up-stroke (compression). Any earlier and it some would be lost through the exhaust camber. Also this amount of leaking nitrous into the expansion chamber may affect the role of the expansion chamber as the exhaust gases are now too cool for the extraction process. Any later on upstroke and there would be little time to 'squirt' the required amount, especially at higher rpms. There should be no injection on the down stroke for the obvious reasons of cooling the exhaust gas charge and affecting the extraction process, and also the waste of unused nitrous out the exhaust system. The exact timing of direct injection of nitrous would need to be tested and tuned, but through the head, and not through the camber, seems the better method to me.

Removing the injection of nitrous in the chamber altogether seems the ideal solution. Then there would be no need to fret about air/fuel/oil mix etc.

I agree Ruby, i think a direct shot straight into the cylinder would definately be the way to do it. I don't think it would be incredibly hard to do either.

If the NOS shot was controlled by a solenoid valve or something, you could wire up another set of contacts onto the flywheel, similar to those for your ingnition coil. When the flywheel magnets go past the new set of contacts, the valve could open for a set period of time to inject the nitrous into the cylinder.

If i had the time and the money, its something i'd have a look at myself, but being short of both at the minute...it might just have to remain as a pipe dream!!

 

[Ruby]

I agree. Tapping into the head is far easier than farting about with oils and mixes, or remaking a new expansion chamber.

Wouldn't be too hard to use an old analog MicroTech D4S or Haltech F9 ECU to control the nitrous. The ECU could easily get its signal from the -ve of the coil. That will eliminate the need for more hardware (contacts etc). Then within the software tune the injector to fire a number of degrees/timing from TDC. And alter the duration for a short burst. Try to keep the burst as short as possible, maybe even use a larger cc/min injector if more nitrous is required but keeping duration short.

That reminds me ... me and a mate are going to fit nitrous to his postie bike CT110. Only its not a 110 anymore. It has a 150cc race engine! LOL

Hmm, all this talking now makes me want to fit nitrous to my 1600. LOL

 

[mech_eng_matty]

Once the nitrous is in the chamber, would there be a problem with
a) the density of the gas being smaller hence the chamber not being filled as much as usual
b) lack of fuel in the system causing a lean out and detonation

I know when turboing or supercharging (which is similar principle to running NO2) you have to increase fuel to stop the lean out from happening, do you think that running a shot of nitrous would cause the same problem?

I would definately NEVER run a Haltech system of any sort!! Tried to use a Haltech E11 on our FSAE car and had so so so many problems!! Replaced it with a Motec M4 and it was essentially just plug and play. I'm real shy about Haltech stuff now, even if it is just their sensors coz we had trouble with a Haltech O2 sensor as well!!

A mate of mine is building a Hotty 1600 at the minute, i can't give u a list of mods coz its been a while since i've spoken to him but i know he's putting a WRX turbo on it, had some head work done, he's running a Haltech E6X, designed his own intake, should be a pretty sweet little machine when he's done.

 

[Hillz]

what a good read ^^

 

[mech_eng_matty]

I spoke to a few guys i work with at lunchtime about the whole 2 stroke nitrous thing, and we kind of determined that there was no real reason that it couldn't be done.

One of them just sent me through an email with the following link;

Motorcycle Accessories Nitrous Oxide Injection Snowmobiles Jet Ski's

Apparantly they make a NOS system for 2 stroke Motorcycles and ATV's as well as Snowmobiles and Watercraft...obviously it can be done...i just wonder with how much work!!

 

[Hillz]

my boss here has NOS on his A80 2-stroke (vintage road bike)

 

[pegleg]

Find how he went about doing it for us Hillz, I would like to see some input in this thread from someone who has tried, and successfully done this!

 

[mech_eng_matty]

I'm with the pirate ^^^^^^

I'd be keen to find out how it was done.

 

[Ruby]

^^^ I'm with stupid ^^^

I know that on paper it should require alot of thinking to make it work. But we know in reality people build projects that just amaze us.



Matty, I've never had a problem with the F9. I've had it fitted to my turboed CBR drag bike and it worked like a charm, and the unit is now in my 1600. BTW, this should get a guy like you drooling:

I've got a CA18DET in the 1600 running a top mount VG30BB turbo on mandrel bends! Massive 320mm vented rotors and 4 pot Hilux calipers up front on adjustable 240K struts with 55mm spring kit. Adjustable lower control arms and adjustable radius rods. Supported by a 25mm heavy duty sway bar. R33 Skyline 5 speed box (rebuilt) with 3 inch balanced tailshaft into a H190 LSD rear axle off a series 3 Bluebird (the stronger diff and 29 spline axles) and custom rear disc brake conversion. On the rails are 550cc rotary injectors. Massive bar and plate intercooler. 58mm throttle body conversion. Plus more I can't recall right now. LOL

 

[pegleg]

Hey again,
Just in reference to the viscosity problem we were talking about earlier, I asked the missus and she said that depending on the quality and grade of oil used.
all good oils contain viscosity modifiers to prevent the change in the viscosity.

 

[mech_eng_matty]

Pegleg,

I'm a bit confused as to how an oil can contain a viscosity modifier. I understand the principle behind it, but wouldn't this change the viscosity rating to a single number instead of a 10W40 or 15W50 where as i understand it the first number is the cold viscosity and the second number is the hot viscosity...or is it the other way around, i can never remember!!!

Anyway, wouldn't this mean that the rating would end up being 40W or 50W or something singular?? I don't believe i've ever seen that.

 

[pegleg]

Pegleg,

I'm a bit confused as to how an oil can contain a viscosity modifier. I understand the principle behind it, but wouldn't this change the viscosity rating to a single number instead of a 10W40 or 15W50 where as i understand it the first number is the cold viscosity and the second number is the hot viscosity...or is it the other way around, i can never remember!!!

Anyway, wouldn't this mean that the rating would end up being 40W or 50W or something singular?? I don't believe i've ever seen that.

Matty,
the answer to this will have to wait until tomorrow night, as the better half has gone to bed.

 

[mech_eng_matty]

There is only one thing i can say to that Pegleg...

You should go and join her!!!!!

Mind you, i would say this, my missus lives in melbourne, an hour and a half away from me, i only get to see her on the weekends

No worries mate, look forward to hearing your response

Cheers

 

[pegleg]

where do I have been for the last 2 hours? lol

 

[Cactus Jack]

Nitrous oxide would be best injected (along with carefully metered additional fuel) via a solenoid activated spray bar between the carb and the inlet manifold ! Since it works by increasing the density of the air BEFORE it enters the engine , the closer to the carby it is , the better it will work . You want to get the air cold and dense before it passes the reeds or inlet valve - then once it's in there - it's trapped and is forced to do its' job of boosting cylinder pressure when burnt !

The engine will still draw in the same volume of air/fuel mix as normal - only the colder charge will be denser and will expand to a greater volume when heated by combustion than it would if it was at normal temperature . Mechanical blowers work by pumping a greater volume of air/fuel mix into an engine at boosted pressure levels and at normal temperature ! Nitrous oxide injection compacts the fuel /air mix by chemically reducing its' temperature which in turn increases it's density at normal atmospheric pressure .

A reed valve is simply a one way valve - the intake charge opens the reed petals in the direction of flow but forces them closed if the flow tries to reverse - so once the denser charge passes the reeds , it doesn't matter if it starts expanding in the cases because the increased pressure would still make it to the cylinder .

You have to remember that everything is happening thousands of times per minute so there isn't much time for the charge to start heating up before it reaches the cylinder and is ignited ! IF the oil did happen to increase viscosity due to lowered temperature - that would actually be a bonus because the increased film strength would help to keep metal parts such as the bearing rollers wedged away from the crank pin and the piston away from the cylinder wall - reducing wear and friction !

2 strokes are poorly lubricated as it is - so you have to ensure that they don't run too rich because the fuel "washes" the oil off the parts - weakening it's ability to keep them away from each other ! In a well tuned 2 stroke engine the fuel turns into a gas and the oil falls out of suspension - adhering to the working components . The spinning crank keeps everything churned up in the cases .

It would be safe to say that the use of nitrous oxide in a 2 stroke engine would require a fine balancing act as far as tuning goes ~ there'd be a fine line between life and death of the engine !

 

[mech_eng_matty]

Mechanical blowers work by pumping a greater volume of air/fuel mix into an engine at boosted pressure levels and at normal temperature !

I will only add one thing to this jack. A mechanical blower, or a turbo for that matter will actually increase the air temperature by a certain amount. This happens because when air is increased in pressure, the temperature increases with it (due to a change in enthalpy).

I'm not gonna go into a bit thermodynamic calculation to prove it but you can chose to reguard it or disreguard it.

This phenomenom is the reason that intercoolers are used. The air temp increases after passing through the compressor hence making a smaller temperature differential inside the combustion chamber and reducing the effectiveness of the boosting. By passing the compressed air through an intercooler, the compressed air gets reduced in temp again before entering the combustion chamber. This essentially gets it back to a similar point as where it would be after using nitrous.

Also, the main advantage of using Nitrous is not as much the cooling of the air, but the fact that the air/fuel mixture gets bombarded with extra oxygen from the nitrous oxide (give its chemical composition of 1 nitrogen molecule to 2 oxygen molecules....NO2) which allows you to burn more fuel for the same amount of air going into the combustion chamber.
An internal combustion engine's major limitation is how much air it can get into its combustion chamber...hence why turbos, superchargers and nitrous are used, they all in a manner of speaking, increase the amount of air (and oxygen molecules) in the engine.

 

[THUMPY125]

i'm with mech_eng_matty, they are not really nos they used to sell them on ebay for $400, you would proabbly find that its a nitro fuel from what some of you guys run your rc cars on.