37 replies to this topic

[MatsNorway]

We are in the process of attempting to make a drag racer out of a 50CC scooter as there is a 50CC class being run once a year organised by a bike club.

From the first day my collegue said he wanted to run nitromethanol and i initially said no way!

But after some reading about it i have chanced my mind, it is possible to run some nitromethanol it seems. It is also legal by the rules ofc. (no fuel restrictions)

After some discussion back and forth we have come to the conclusion that running a normal gas engine with either a separate nozzle for the nitromethane with manual activation, or with a extra carb (two in serial) should be a doable solutions.

The reasoning is that by running it dominantly as a gas engine it will not so easily run lean as the petrol part is allready tuned in without the nitro.

Running it as a petrol engine will ease the start up and we can engage the nitromethane separately.

We intend to run RC fuel as it has the oils needed and all that.

I am however a bit confused to how to tune to it. My initial idea was way less compression and very rich mixture as well as a very open exhaust system to avoid any form of missfire.

Another thing if we get real serious is that the ignition needs to be way in advance as the nitro burns slowly.

Any info and some thoughts about this is allways appreciated.

http://www.hotrod.co...ay/viewall.html
http://www.klotznitromethane.com/
http://www.motorspor...rAdditives.html

I guess the first question would be: how much nitromethanol? For starters so that there a noticable bump in hp. (We can not mix it directly in the tank it seems as the nitro reacts with the hydrocarbons)

Info about and where to buy toulene, acetone, Propylene Oxide and castor oil would be nice.

Edited by MatsNorway, 10 July 2013 - 13:19.

[Bob Riebe]

NitroMethane does not mix with gasoline, nitropropane does.

If you want to run nitromethane use the premixed fuel for sale for model airplanes. It is available at may hobby stores, unless you plant to buy by the barrel.

Do not try to mix gasoline and nitro-alcohol.

[Lee Nicolle]

Nitromethane is always mixed with methanol. The percentage is the key. Fuel Dragsters run a fairly large percentage and in the old days many speedway categorys used to cheat by using small percentages. Too large a percentage usually made the pistons into ashtrays! In a 4 lap race. And in the pit area it was not hard to work out it was being used, it made your eyes burn!

I am sure there is many on this forum who know far more about percentages though I do know it does not mix with petrol and is quite corrosive to boot.

Edited by Lee Nicolle, 11 July 2013 - 03:43.

[Kelpiecross]

Mats - is the 50cc engine two or four stroke? What make of engine is it?
If is a 4-stroke (or possibly a 2-stroke) a supercharger would be good. I have heard exhaust air injection pumps can be used to supercharge 50cc engines. Nitrous oxide may be more convenient than nitromethane. To be really radical - oxygen out of a bottle would interesting (Mickey Thompson and others have tried this).

Castor oil - you can still buy Castrol R - which is mainly castor oil. Acetone from fibreglass material supply shops. Toluene I don't know but acrylic lacquer thinners is about half toluene so it can't be difficult to get.

[MatsNorway]

Mats - is the 50cc engine two or four stroke? What make of engine is it?
If is a 4-stroke (or possibly a 2-stroke) a supercharger would be good. I have heard exhaust air injection pumps can be used to supercharge 50cc engines. Nitrous oxide may be more convenient than nitromethane. To be really radical - oxygen out of a bottle would interesting (Mickey Thompson and others have tried this).

Castor oil - you can still buy Castrol R - which is mainly castor oil. Acetone from fibreglass material supply shops. Toluene I don't know but acrylic lacquer thinners is about half toluene so it can't be difficult to get.

Thanks for the info

Its a two stroke and yes a compressor would be nice but its probably way to complicated to do for us. and i have no idea where to get a suitable compressor.

Nitrous might give us 5-20% increase (i don`t know) but i do know it would probably be more costly and advanced than nitro.

Edited by MatsNorway, 11 July 2013 - 15:05.

[Lee Nicolle]

The street drag blokes I know reckon that NOS is good for half a second on the 1/4. That on 11-1 V8 Chevs and Holdens. That computes to quite a deal of power.And it seems if you do not go to radical the engines live.

[Anthem]

May want to search out "GO-PED" scooters, we use to race around the pits (mid-late 90's) on these...racers being racers modifications soon entered the scene and progressed to being outlawed in the pits. Zipping around 30-50 mph with little trails of 2-stroke smoke in a crowded pits was fun I have to say!

Castor oil, no need to burn-the-bean, unless your into the smell of nostalgia. Try yamalude 2R, klotz, etc... Pre-mix it's easy and lightweight (no mixture pump or oil tank).

Edited by Anthem, 11 July 2013 - 23:29.

[gruntguru]

Many 2 stroke lubes will not blend with alcohol.

Oxygen is nowhere near as effective as Nitrous because it causes detonation.

Edited by gruntguru, 12 July 2013 - 04:40.

[Bob Riebe]

If you want some hard info on alcohol fired two-strokes, try to get a hold of some of the boys who tuned snowmobiles for the professional circuit up to about 1970.
Many used exotic alcohol blends till they were banned.

[scolbourne]

Model aircraft fuel is the simplest way to go. You will need to enlarge the fuel jets and ideally change the ignition timing for best results. The fuel comes ready mixed and is available in various mixture ratios.

There is a problem of some seals and gaskets dissolving sometimes, but they will probably survive long enough for your purposes.

[MatsNorway]

Quite right. When it comes to gaskets and such i think we need to just let it run on idle with petrol for a while to get it "clean" from nitro

If we are to make fuel systems, Would stainless steel do the trick? Other materials?

Many 2 stroke lubes will not blend with alcohol.

So i take it castor oil is a must have if we where to mix our own fuel.

Page with info on O-rings and compability with Nitromethane
http://www.efunda.co...SC=Nitromethane

Edited by MatsNorway, 12 July 2013 - 10:37.

[MatsNorway]

http://www.retronaut...ic-for-peugeot/

Racing back in the day was no joke.

[MatsNorway]

So Nitromethane does not eat brass or Copper??????

Why im asking: http://www.gpmd.com/...s/lsupg1814.jpg

Edited by MatsNorway, 17 July 2013 - 20:26.

[Canuck]

I don't have permission to view that...

[MatsNorway]

Fixed it.

What we will try to do is to do like they do on RC engines and just put pressure on the fuel tank by the exhaust system. Eliminating the floater thingy (what is it called?) as we reasoned it to be a pressure eliminator making it possible for the engine to such out the fuel it needed. Surely a proper carb got a movable needle valve i thought but whatever as those small nitro engines seems to not have that. Once you choke the air for the engine you remove the pressure in the fuelsystem so it goes around like that it seems.

So it goes something like this. We drill a hole in the intake and mount it after and in serial with the petrol carburetor and by doing so we do not need to make a butterfly valve or anything like that. Airflow is done by the carburetor and if we add a small pressure dependent valve we can tune it to cut nitro on whatever not full throttle setting. As that would not give exhaust gas enought to get the pressure needed to open the valve.

This should make it easier to drive and start.

Nitromethane nozzle
https://dl.dropboxus...20nitrodyse.bmp

But after some thinking about it my collegue was wondering if we could just use an adjustable valve from pneumatics. So if we can find one in say stainless we will try that first.

Edited by MatsNorway, 17 July 2013 - 20:50.

[gruntguru]

Needle valve?

[Greg Locock]

Needle valve?

Tapered pin in a tapered socket, almost exactly like the fuel metering needle on an SU carb. On an RC engine you adjust the mixture by backing the needle valve out on a screw thread, and then hope Bernouilli does his job.

[Tony Matthews]

[saudoso]

Oh the joy of burnt castor oil smell. Brings tears to my eyes, simpler times and all that.

Edited by saudoso, 18 July 2013 - 09:29.

[Tony Matthews]

Oh the joy of burnt castor oil smell. Brings tears to my eyes, simpler times and all that.

Plus the joy of being caught on the back of the index finger by a 12"x 6" Nylon prop, the fuel getting into the razor cuts on you hands, and the first flight after months of work resulting in devastating crash and ritual bonfire.

[MatsNorway]

Needle valve it is. But it is also a nozzle.

Modern nitro engines got no big shapes like that on the piston. Other than that they are pretty much identical.

Edited by MatsNorway, 18 July 2013 - 22:53.

[scolbourne]

http://www.elsberg-t...ecordbikes.html

Quite an impressive 50cc bike on this site which achieved 233 km/h (about 145mph) . There is also a description of an earlier attempt that is relevant here.


When we tested the engine, which in Italy gave about 21HP we saw only about 12HP, an incredible
loss! We tried to improve this using alcohol and nitro, but improved only to about 15HP".

"Vaifro's chief mechanic Marcello Quintana had prepared something special however, a NOS
(Nitrous Oxide) injection which gave a dramatic improvement.
To fit the injector we had to fit a longer inlet rubber, the now longer inlet tract made a
longer inlet timing necessary, which made the engine a lot more difficult to start.
This became a big problem!
When it started it gave about 23-24HP, quite incredible. This means that at sea level we would
have had maybe 30HP!"

[MatsNorway]

Thank you! bookmarked.

On an RC engine you adjust the mixture by backing the needle valve out on a screw thread, and then hope Bernouilli does his job.

It is also pressurised by the exhaust system. Boosting the fuel flow. As seen here. http://www.neobuggy...._1707-copia.jpg

As previously mentioned i believe we might make a pressure release valve to make it only feed on full tilt.

Edited by MatsNorway, 18 July 2013 - 22:58.

[Magoo]

Plus the joy of being caught on the back of the index finger by a 12"x 6" Nylon prop, the fuel getting into the razor cuts on you hands, and the first flight after months of work resulting in devastating crash and ritual bonfire.

Or you execute a perfect maiden flight and landing, whereupon a large dog runs away with it.

[Tony Matthews]

Ha ha - yes, a distinct possibility. In my case, a big risk was that the cows would encircle the grounded plane and deny access, or trample it.

[desmo]

http://www.elsberg-t...ecordbikes.html

Quite an impressive 50cc bike on this site which achieved 233 km/h (about 145mph) . There is also a description of an earlier attempt that is relevant here.


When we tested the engine, which in Italy gave about 21HP we saw only about 12HP, an incredible
loss! We tried to improve this using alcohol and nitro, but improved only to about 15HP".

"Vaifro's chief mechanic Marcello Quintana had prepared something special however, a NOS
(Nitrous Oxide) injection which gave a dramatic improvement.
To fit the injector we had to fit a longer inlet rubber, the now longer inlet tract made a
longer inlet timing necessary, which made the engine a lot more difficult to start.
This became a big problem!
When it started it gave about 23-24HP, quite incredible. This means that at sea level we would
have had maybe 30HP!"

Wow, never seen a SI 2-stroke with a turbo fitted before. Even kept the expansion chamber!

[MatsNorway]

Where did they get the turbo i wonder.

[JacnGille]

Plus the joy of being caught on the back of the index finger by a 12"x 6" Nylon prop, the fuel getting into the razor cuts on you hands, and the first flight after months of work resulting in devastating crash and ritual bonfire.

[KjetilS]

As previously mentioned i believe we might make a pressure release valve to make it only feed on full tilt.

Is it possible to make it simple by using a electric pump to pump the fuel? Like a windscreen washer pump? And then use a needle valve to tune the mixture at full trottle?

[MatsNorway]

Is it possible to make it simple by using a electric pump to pump the fuel? Like a windscreen washer pump? And then use a needle valve to tune the mixture at full trottle?

We started there but after looking into the carburetors of nitro rc cars it could scale the pressure nicely with throttle position so i think its a good idea.

Having a pump also means you need a pressure release valve anyway so why not just use that too and keep the rest RC car parts. fuel tank and lines. So simple. All we need is two or one more valve. I have sourced a Festo stainless valve for the flow control. Not sure about the gasket materials. Syntetic Rubber something.
http://www.festo.com...asp?qry=GRLZ-M3

It will appear after choosing region and country.

We will se. a big fat red button to engage scary time sounds fun too. Could be easier to get working if the pressure release is not precise.

Edited by MatsNorway, 02 February 2014 - 12:09.

[Kelpiecross]

I may have missed something - but why are you planning something like a pseudo constant flow FI system and not just modifying a normal carburettor? I think you will find the pseudo FI system just about impossible to make work properly. It is difficult enough to make a two-stroke engine run properly at the best of times.

I don't know about using normal model glow plug fuel either. I t probably has a lot more oil than you need. Also the 10-15% nitro in model fuel is not so much for extra power but to make the engine run better generally and more controllably.

"Big red button" control would be simpler with nitrous.

Edited by Kelpiecross, 24 July 2013 - 02:56.

[Canuck]

I tend to agree. Any idiot can run nitrous - even I managed it. Granted it wasn't on something that small but it seems (to me) far more forgiving. A simple setup would entail a little bottle, one nozzle in the plenum, 2 solenoids, a fuel line (or dedicated little fuel pump if gravity-fed carb), a safety switch and a fun-button. Easy. I probably have all the parts in my garage in fact. Much easier than fooling with nitro.

[MatsNorway]

Can`t run Nitro in regular carb. It will over time get eaten by the nitro. Where just adding a extra nozzle after the carb. They where out watching a race yesterday and they reported rc car smell from some of them.

 

You can get up to 45% Nitro over the counter

 

I think that since its a two-stroke it might cause a issue in running lots of nitro.

Edited by MatsNorway, 15 September 2013 - 15:23.

[MatsNorway]

As requested, here is some photos of the thingy so far.

 

Big pictures of the frame and details. We opted for a non symmetric design on the frame to give room for a potentially big exhaust system.

 

https://dl.dropboxus...iv/IMAG0243.jpg

 

Petrol tank in the frame: https://dl.dropboxus...iv/IMAG0246.jpg

Where to fill it up. https://dl.dropboxus...iv/IMAG0248.jpg

 

Soldering for the linkage mount where we set the ride height++

https://dl.dropboxus...iv/IMAG0254.jpg

 

Found a fully manual way to grind curves smoothly on the stone (this is the other end of the linkage mount)

https://dl.dropboxus...iv/IMAG0258.jpg

 

Grinded and smoothed down.

https://dl.dropboxus...iv/IMAG0260.jpg

 

We are going for white paint.. so we can se cracks in the rail easier ive been told.

Edited by MatsNorway, 02 February 2014 - 11:08.

[scolbourne]

Can you describe what kind of engine and fuel mix you decided to use.

[MatsNorway]

Those things have not been decided yet. I am wondering if the 50cc monkey bikes has engines where you could switch the crank to a 125ccm versjon. If so that is the end goal. I also believe four-stroke to be better suited for nitromethane running.

 

The two peugeot speedfight motors we have will be testbeds for running nitromethane.

Edited by MatsNorway, 04 February 2014 - 17:45.

[MatsNorway]

Rolling chassie done. Got a bit lucky wit the frame and the exhaust. I was arguing against it as it s not as strong, wanted to have the verticals like a regular frame. But he had his way as he allways gets.

We will probably test with stock front but it might become too weak because of the angle.. Bicycle front if so.

 

Needs to start it first and then we might start gently testing the nitro.

Edited by MatsNorway, 02 September 2014 - 06:26.

[mariner]

If the following is stupid I apologize in advance!

 

IIRC the most powerful nitro burning drag cars all use fuel injection. I know nitro will work in a carb. but I think that drag racers learnt quicky that better atmomisaion was key to unlocking nitro power. That led to finer jet nozzles and more line pressure to improve the atomisation.

 

I think two young drag racers in California did very well because their Dad was a manufacturing jeweller so they had acces to the tools to biuld fine nozzles on their car.

Edited by mariner, 02 September 2014 - 08:26.